add AccessibilityDriver for testing Accessibility

This is the first cut with known issues, e.g. needs to handle
click on EditText differently, etc. Thic cl sets up the architecture
of AccessibilityDriver; details will be filled in follow-up cls.

Change-Id: I2881b28075eba478a5aad9d7e945b5d55e78da89

29 files changed, 1169 insertions, 412 deletions

diff --git a/src/com/google/android/droiddriver/UiElement.java b/src/com/google/android/droiddriver/UiElement.java
index a2e7017..fc75e5b 100644
--- a/src/com/google/android/droiddriver/UiElement.java
+++ b/src/com/google/android/droiddriver/UiElement.java
@@ -19,7 +19,6 @@ package com.google.android.droiddriver;
 import android.graphics.Rect;
 
 import com.google.android.droiddriver.actions.Action;
-import com.google.android.droiddriver.actions.InputInjector;
 import com.google.android.droiddriver.exceptions.ElementNotVisibleException;
 import com.google.android.droiddriver.finders.Attribute;
 import com.google.android.droiddriver.finders.Predicate;
@@ -152,7 +151,6 @@ public interface UiElement {
    * @param text The text to enter.
    * @throws ElementNotVisibleException when the element is not visible
    */
-  // TODO: Should this clear the text before setting?
   void setText(String text);
 
   /**
@@ -180,7 +178,11 @@ public interface UiElement {
   void doubleClick();
 
   /**
-   * Scrolls in the given direction. Scrolling down means swiping upwards.
+   * Scrolls in the given direction.
+   *
+   * @param direction specifies where the view port will move, instead of the
+   *        finger.
+   * @throws ElementNotVisibleException when the element is not visible
    */
   void scroll(PhysicalDirection direction);
 
@@ -226,9 +228,4 @@ public interface UiElement {
    * Gets the parent.
    */
   UiElement getParent();
-
-  /**
-   * Gets the {@link InputInjector} for injecting InputEvent.
-   */
-  InputInjector getInjector();
 }
diff --git a/src/com/google/android/droiddriver/actions/Action.java b/src/com/google/android/droiddriver/actions/Action.java
index 86dfc24..fd5068e 100644
--- a/src/com/google/android/droiddriver/actions/Action.java
+++ b/src/com/google/android/droiddriver/actions/Action.java
@@ -16,25 +16,23 @@
 
 package com.google.android.droiddriver.actions;
 
-import android.view.InputEvent;
-
 import com.google.android.droiddriver.UiElement;
 
 /**
  * Interface for performing action on a UiElement. An action is a high-level
- * user interaction that consists of a series of {@link InputEvent}s.
+ * user interaction that can be performed in various ways, for example, via
+ * synthesized events, or the Accessibility API.
  */
 public interface Action {
   /**
    * Performs the action.
    *
-   * @param injector the injector to inject {@link InputEvent}s
    * @param element the Ui element to perform the action on
    * @return Whether the action is successful. Some actions throw exceptions in
    *         case of failure, when that behavior is more appropriate. For
    *         example, if event injection returns false.
    */
-  boolean perform(InputInjector injector, UiElement element);
+  boolean perform(UiElement element);
 
   /**
    * Gets the timeout to wait for an indicator that the action has been carried
@@ -50,7 +48,7 @@ public interface Action {
    *
    * <p>
    * It is recommended that this method return the description of the action,
-   * for example, "TypeAction{text to type}".
+   * for example, "SwipeAction{DOWN}".
    */
   @Override
   String toString();
diff --git a/src/com/google/android/droiddriver/actions/ClickAction.java b/src/com/google/android/droiddriver/actions/ClickAction.java
index 9050b19..0d7350d 100644
--- a/src/com/google/android/droiddriver/actions/ClickAction.java
+++ b/src/com/google/android/droiddriver/actions/ClickAction.java
@@ -26,7 +26,7 @@ import com.google.android.droiddriver.util.Events;
 /**
  * An action that does clicks on an UiElement.
  */
-public abstract class ClickAction extends BaseAction {
+public abstract class ClickAction extends EventAction {
 
   public static final ClickAction SINGLE = new SingleClick(1000L);
   public static final ClickAction LONG = new LongClick(1000L);
@@ -41,8 +41,8 @@ public abstract class ClickAction extends BaseAction {
 
     @Override
     public boolean perform(InputInjector injector, UiElement element) {
-      SINGLE.perform(injector, element);
-      SINGLE.perform(injector, element);
+      SINGLE.perform(element);
+      SINGLE.perform(element);
       return true;
     }
   }
diff --git a/src/com/google/android/droiddriver/actions/EventAction.java b/src/com/google/android/droiddriver/actions/EventAction.java
new file mode 100644
index 0000000..71ceb6f
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/EventAction.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions;
+
+import android.view.InputEvent;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.base.BaseUiElement;
+
+/**
+ * Implements {@link Action} by injecting synthesized events.
+ */
+public abstract class EventAction extends BaseAction {
+  protected EventAction(long timeoutMillis) {
+    super(timeoutMillis);
+  }
+
+  @Override
+  public boolean perform(UiElement element) {
+    return perform(((BaseUiElement) element).getInjector(), element);
+  }
+
+  /**
+   * Performs the action by injecting synthesized events.
+   *
+   * @param injector the injector to inject {@link InputEvent}s
+   * @param element the UiElement to perform the action on
+   * @return Whether the action is successful. Some actions throw exceptions in
+   *         case of failure, when that behavior is more appropriate. For
+   *         example, if event injection returns false.
+   */
+  protected abstract boolean perform(InputInjector injector, UiElement element);
+}
diff --git a/src/com/google/android/droiddriver/actions/EventUiElementActor.java b/src/com/google/android/droiddriver/actions/EventUiElementActor.java
new file mode 100644
index 0000000..dbee143
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/EventUiElementActor.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.base.UiElementActor;
+import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+
+/**
+ * A {@link UiElementActor} that performs actions by injecting synthesized
+ * events.
+ */
+public class EventUiElementActor implements UiElementActor {
+  public static final EventUiElementActor INSTANCE = new EventUiElementActor();
+
+  @Override
+  public void setText(UiElement uiElement, String text) {
+    uiElement.perform(new TextAction(text));
+  }
+
+  @Override
+  public void click(UiElement uiElement) {
+    uiElement.perform(ClickAction.SINGLE);
+  }
+
+  @Override
+  public void longClick(UiElement uiElement) {
+    uiElement.perform(ClickAction.LONG);
+  }
+
+  @Override
+  public void doubleClick(UiElement uiElement) {
+    uiElement.perform(ClickAction.DOUBLE);
+  }
+
+  @Override
+  public void scroll(UiElement uiElement, PhysicalDirection direction) {
+    uiElement.perform(SwipeAction.toScroll(direction));
+  }
+}
diff --git a/src/com/google/android/droiddriver/actions/KeyAction.java b/src/com/google/android/droiddriver/actions/KeyAction.java
index 1855b21..18bbd4c 100644
--- a/src/com/google/android/droiddriver/actions/KeyAction.java
+++ b/src/com/google/android/droiddriver/actions/KeyAction.java
@@ -22,7 +22,7 @@ import com.google.android.droiddriver.exceptions.ActionException;
 /**
  * Base class for {@link Action} that injects key events.
  */
-public abstract class KeyAction extends BaseAction {
+public abstract class KeyAction extends EventAction {
   private final boolean checkFocused;
 
   protected KeyAction(long timeoutMillis, boolean checkFocused) {
diff --git a/src/com/google/android/droiddriver/actions/SwipeAction.java b/src/com/google/android/droiddriver/actions/SwipeAction.java
index 9e2cfbe..a939536 100644
--- a/src/com/google/android/droiddriver/actions/SwipeAction.java
+++ b/src/com/google/android/droiddriver/actions/SwipeAction.java
@@ -28,9 +28,9 @@ import com.google.android.droiddriver.util.Strings;
 import com.google.android.droiddriver.util.Strings.ToStringHelper;
 
 /**
- * A {@link ScrollAction} that swipes the touch screen.
+ * An action that swipes the touch screen.
  */
-public class SwipeAction extends ScrollAction {
+public class SwipeAction extends EventAction {
   // Milliseconds between synthesized ACTION_MOVE events.
   // Note: ACTION_MOVE_INTERVAL is the minimum interval between injected events;
   // the actual interval typically is longer.
diff --git a/src/com/google/android/droiddriver/actions/accessibility/AccessibilityAction.java b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityAction.java
new file mode 100644
index 0000000..4d47eac
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityAction.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions.accessibility;
+
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.actions.Action;
+import com.google.android.droiddriver.actions.BaseAction;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationElement;
+
+/**
+ * Implements {@link Action} via the Accessibility API.
+ */
+public abstract class AccessibilityAction extends BaseAction {
+  protected AccessibilityAction(long timeoutMillis) {
+    super(timeoutMillis);
+  }
+
+  @Override
+  public boolean perform(UiElement element) {
+    return perform(((BaseUiAutomationElement<?>) element).getNode(), element);
+  }
+
+  /**
+   * Performs the action via the Accessibility API.
+   *
+   * @param node the AccessibilityNodeInfo used to create the UiElement
+   * @param element the UiElement to perform the action on
+   * @return Whether the action is successful. Some actions throw exceptions in
+   *         case of failure, when that behavior is more appropriate.
+   */
+  protected abstract boolean perform(AccessibilityNodeInfo node, UiElement element);
+}
diff --git a/src/com/google/android/droiddriver/actions/accessibility/AccessibilityClickAction.java b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityClickAction.java
new file mode 100644
index 0000000..4a4033c
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityClickAction.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions.accessibility;
+
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.exceptions.ActionException;
+
+/**
+ * An {@link AccessibilityAction} that clicks on an UiElement.
+ */
+public abstract class AccessibilityClickAction extends AccessibilityAction {
+
+  public static final AccessibilityClickAction SINGLE = new SingleClick(1000L);
+  public static final AccessibilityClickAction LONG = new LongClick(1000L);
+  public static final AccessibilityClickAction DOUBLE = new DoubleClick(1000L);
+
+  protected AccessibilityClickAction(long timeoutMillis) {
+    super(timeoutMillis);
+  }
+
+  public static class DoubleClick extends AccessibilityClickAction {
+    public DoubleClick(long timeoutMillis) {
+      super(timeoutMillis);
+    }
+
+    @Override
+    protected boolean perform(AccessibilityNodeInfo node, UiElement element) {
+      return SINGLE.perform(element) && SINGLE.perform(element);
+    }
+  }
+
+  public static class LongClick extends AccessibilityClickAction {
+    public LongClick(long timeoutMillis) {
+      super(timeoutMillis);
+    }
+
+    @Override
+    protected boolean perform(AccessibilityNodeInfo node, UiElement element) {
+      if (!element.isLongClickable()) {
+        throw new ActionException(element
+            + " is not long-clickable; maybe there is a clickable element in the same location?");
+      }
+      return node.performAction(AccessibilityNodeInfo.ACTION_LONG_CLICK);
+    }
+  }
+
+  public static class SingleClick extends AccessibilityClickAction {
+    public SingleClick(long timeoutMillis) {
+      super(timeoutMillis);
+    }
+
+    @Override
+    protected boolean perform(AccessibilityNodeInfo node, UiElement element) {
+      if (!element.isClickable()) {
+        throw new ActionException(element
+            + " is not clickable; maybe there is a clickable element in the same location?");
+      }
+      return node.performAction(AccessibilityNodeInfo.ACTION_CLICK);
+    }
+  }
+
+  @Override
+  public String toString() {
+    return getClass().getSimpleName();
+  }
+}
diff --git a/src/com/google/android/droiddriver/actions/accessibility/AccessibilityScrollAction.java b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityScrollAction.java
new file mode 100644
index 0000000..88e7517
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityScrollAction.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions.accessibility;
+
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+import com.google.android.droiddriver.util.Strings;
+
+/**
+ * An {@link AccessibilityAction} that scrolls an UiElement.
+ */
+public class AccessibilityScrollAction extends AccessibilityAction {
+  private final PhysicalDirection direction;
+
+  public AccessibilityScrollAction(PhysicalDirection direction) {
+    this(direction, 1000L);
+  }
+
+  public AccessibilityScrollAction(PhysicalDirection direction, long timeoutMillis) {
+    super(timeoutMillis);
+    this.direction = direction;
+  }
+
+  @Override
+  protected boolean perform(AccessibilityNodeInfo node, UiElement element) {
+    if (!element.isScrollable()) {
+      return false;
+    }
+
+    switch (direction) {
+      case UP:
+      case LEFT:
+        return node.performAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
+      case DOWN:
+      case RIGHT:
+        return node.performAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
+    }
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    return Strings.toStringHelper(this).addValue(direction).toString();
+  }
+}
diff --git a/src/com/google/android/droiddriver/actions/accessibility/AccessibilityUiElementActor.java b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityUiElementActor.java
new file mode 100644
index 0000000..491ad7a
--- /dev/null
+++ b/src/com/google/android/droiddriver/actions/accessibility/AccessibilityUiElementActor.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.actions.accessibility;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.actions.TextAction;
+import com.google.android.droiddriver.base.UiElementActor;
+import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+
+/**
+ * A {@link UiElementActor} that performs actions via the Accessibility API.
+ */
+public class AccessibilityUiElementActor implements UiElementActor {
+  public static final AccessibilityUiElementActor INSTANCE = new AccessibilityUiElementActor();
+
+  @Override
+  public void setText(UiElement uiElement, String text) {
+    uiElement.perform(new TextAction(text));
+  }
+
+  @Override
+  public void click(UiElement uiElement) {
+    uiElement.perform(AccessibilityClickAction.SINGLE);
+  }
+
+  @Override
+  public void longClick(UiElement uiElement) {
+    uiElement.perform(AccessibilityClickAction.LONG);
+  }
+
+  @Override
+  public void doubleClick(UiElement uiElement) {
+    uiElement.perform(AccessibilityClickAction.DOUBLE);
+  }
+
+  @Override
+  public void scroll(UiElement uiElement, PhysicalDirection direction) {
+    uiElement.perform(new AccessibilityScrollAction(direction));
+  }
+}
diff --git a/src/com/google/android/droiddriver/base/BaseUiElement.java b/src/com/google/android/droiddriver/base/BaseUiElement.java
index 1478505..ba25874 100644
--- a/src/com/google/android/droiddriver/base/BaseUiElement.java
+++ b/src/com/google/android/droiddriver/base/BaseUiElement.java
@@ -20,9 +20,8 @@ import android.graphics.Rect;
 
 import com.google.android.droiddriver.UiElement;
 import com.google.android.droiddriver.actions.Action;
-import com.google.android.droiddriver.actions.ClickAction;
-import com.google.android.droiddriver.actions.SwipeAction;
-import com.google.android.droiddriver.actions.TextAction;
+import com.google.android.droiddriver.actions.InputInjector;
+import com.google.android.droiddriver.exceptions.DroidDriverException;
 import com.google.android.droiddriver.exceptions.ElementNotVisibleException;
 import com.google.android.droiddriver.finders.Attribute;
 import com.google.android.droiddriver.finders.Predicate;
@@ -37,6 +36,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.FutureTask;
 
 /**
@@ -48,6 +48,12 @@ public abstract class BaseUiElement implements UiElement {
   public static final String ATTRIB_VISIBLE_BOUNDS = "VisibleBounds";
   public static final String ATTRIB_NOT_VISIBLE = "NotVisible";
 
+  private final UiElementActor uiElementActor;
+
+  protected BaseUiElement(UiElementActor UiElementActor) {
+    this.uiElementActor = UiElementActor;
+  }
+
   @SuppressWarnings("unchecked")
   @Override
   public <T> T get(Attribute attribute) {
@@ -152,6 +158,11 @@ public abstract class BaseUiElement implements UiElement {
     return selectionStart >= 0 && selectionStart != selectionEnd;
   }
 
+  /**
+   * Gets the {@link InputInjector} for injecting InputEvent.
+   */
+  public abstract InputInjector getInjector();
+
   @Override
   public boolean perform(Action action) {
     Logs.call(this, "perform", action);
@@ -160,7 +171,7 @@ public abstract class BaseUiElement implements UiElement {
   }
 
   protected boolean doPerform(Action action) {
-    return action.perform(getInjector(), this);
+    return action.perform(this);
   }
 
   protected abstract void doPerformAndWait(FutureTask<Boolean> futureTask, long timeoutMillis);
@@ -180,44 +191,40 @@ public abstract class BaseUiElement implements UiElement {
     doPerformAndWait(futureTask, action.getTimeoutMillis());
     try {
       return futureTask.get();
-    } catch (Exception e) {
-      // should not reach here b/c futureTask has run
-      return false;
+    } catch (ExecutionException e) {
+      Throwable cause = e.getCause();
+      if (cause instanceof RuntimeException) {
+        throw (RuntimeException) cause;
+      }
+      throw new DroidDriverException(cause);
+    } catch (InterruptedException e) {
+      throw new DroidDriverException(e);
     }
   }
 
   @Override
   public void setText(String text) {
-    perform(new TextAction(text));
-    // TextAction may not be effective immediately and reflected by getText(),
-    // so the following will fail.
-    // if (Logs.DEBUG) {
-    // String actual = getText();
-    // if (!text.equals(actual)) {
-    // throw new DroidDriverException(String.format(
-    // "setText failed: expected=\"%s\", actual=\"%s\"", text, actual));
-    // }
-    // }
+    uiElementActor.setText(this, text);
   }
 
   @Override
   public void click() {
-    perform(ClickAction.SINGLE);
+    uiElementActor.click(this);
   }
 
   @Override
   public void longClick() {
-    perform(ClickAction.LONG);
+    uiElementActor.longClick(this);
   }
 
   @Override
   public void doubleClick() {
-    perform(ClickAction.DOUBLE);
+    uiElementActor.doubleClick(this);
   }
 
   @Override
   public void scroll(PhysicalDirection direction) {
-    perform(SwipeAction.toScroll(direction));
+    uiElementActor.scroll(this, direction);
   }
 
   protected abstract Map<Attribute, Object> getAttributes();
diff --git a/src/com/google/android/droiddriver/base/UiElementActor.java b/src/com/google/android/droiddriver/base/UiElementActor.java
new file mode 100644
index 0000000..b7ffe47
--- /dev/null
+++ b/src/com/google/android/droiddriver/base/UiElementActor.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.base;
+
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+
+/**
+ * Interface for performing actions on a {@link UiElement}.
+ */
+public interface UiElementActor {
+  /**
+   * Sets the text of this element.
+   *
+   * @param text The text to enter.
+   */
+  void setText(UiElement uiElement, String text);
+
+  /**
+   * Clicks this element. The click will be at the center of the visible
+   * element.
+   */
+  void click(UiElement uiElement);
+
+  /**
+   * Long-clicks this element. The click will be at the center of the visible
+   * element.
+   */
+  void longClick(UiElement uiElement);
+
+  /**
+   * Double-clicks this element. The click will be at the center of the visible
+   * element.
+   */
+  void doubleClick(UiElement uiElement);
+
+  /**
+   * Scrolls in the given direction.
+   *
+   * @param direction specifies where the view port will move, instead of the
+   *        finger.
+   */
+  void scroll(UiElement uiElement, PhysicalDirection direction);
+}
diff --git a/src/com/google/android/droiddriver/helpers/DroidDrivers.java b/src/com/google/android/droiddriver/helpers/DroidDrivers.java
index a2a195b..c281075 100644
--- a/src/com/google/android/droiddriver/helpers/DroidDrivers.java
+++ b/src/com/google/android/droiddriver/helpers/DroidDrivers.java
@@ -18,17 +18,22 @@ package com.google.android.droiddriver.helpers;
 
 import android.app.Instrumentation;
 import android.os.Build;
+import android.os.Bundle;
 
 import com.google.android.droiddriver.DroidDriver;
 import com.google.android.droiddriver.exceptions.DroidDriverException;
 import com.google.android.droiddriver.instrumentation.InstrumentationDriver;
 import com.google.android.droiddriver.uiautomation.UiAutomationDriver;
 
+import java.lang.reflect.InvocationTargetException;
+
 /**
  * Static utility methods pertaining to {@link DroidDriver} instances.
  */
 public class DroidDrivers {
   private static DroidDriver driver;
+  private static Instrumentation instrumentation;
+  private static Bundle options;
 
   /**
    * Gets the singleton driver. Throws if {@link #init} has not been called.
@@ -54,6 +59,34 @@ public class DroidDrivers {
   }
 
   /**
+   * Initializes for the convenience methods {@link #getInstrumentation()} and
+   * {@link #getOptions()}. Called by
+   * {@link com.google.android.droiddriver.runner.TestRunner}. If a custom
+   * runner is used, this method must be called appropriately, otherwise the two
+   * convenience methods won't work.
+   */
+  public static void initInstrumentation(Instrumentation instrumentation, Bundle arguments) {
+    if (DroidDrivers.instrumentation != null) {
+      throw new DroidDriverException("DroidDrivers.initInstrumentation() can only be called once");
+    }
+    DroidDrivers.instrumentation = instrumentation;
+    DroidDrivers.options = arguments;
+  }
+
+  public static Instrumentation getInstrumentation() {
+    return instrumentation;
+  }
+
+  /**
+   * Gets the <a href=
+   * "http://developer.android.com/tools/testing/testing_otheride.html#AMOptionsSyntax"
+   * >am instrument options</a>.
+   */
+  public static Bundle getOptions() {
+    return options;
+  }
+
+  /**
    * Returns whether the running target (device or emulator) has
    * {@link android.app.UiAutomation} API, which is introduced in SDK API 18
    * (JELLY_BEAN_MR2).
@@ -63,10 +96,33 @@ public class DroidDrivers {
   }
 
   /**
-   * Returns a new UiAutomationDriver if {@link android.app.UiAutomation} is
-   * available; otherwise a new InstrumentationDriver.
+   * Returns a new DroidDriver instance. If am instrument options have "driver",
+   * treat it as the fully-qualified-class-name and create a new instance of it
+   * with {@code instrumentation} as the argument; otherwise a new
+   * platform-dependent default DroidDriver instance.
    */
   public static DroidDriver newDriver(Instrumentation instrumentation) {
+    String driverClass = options == null ? null : options.getString("driver");
+    if (driverClass != null) {
+      try {
+        return (DroidDriver) Class.forName(driverClass).getConstructor(Instrumentation.class)
+            .newInstance(instrumentation);
+      } catch (ClassNotFoundException e) {
+        throw new DroidDriverException(e);
+      } catch (NoSuchMethodException e) {
+        throw new DroidDriverException(e);
+      } catch (InstantiationException e) {
+        throw new DroidDriverException(e);
+      } catch (IllegalAccessException e) {
+        throw new DroidDriverException(e);
+      } catch (IllegalArgumentException e) {
+        throw new DroidDriverException(e);
+      } catch (InvocationTargetException e) {
+        throw new DroidDriverException(e);
+      }
+    }
+
+    // If "driver" is not specified, return default.
     if (hasUiAutomation()) {
       return newUiAutomationDriver(instrumentation);
     }
@@ -81,9 +137,8 @@ public class DroidDrivers {
   /** Returns a new UiAutomationDriver */
   public static UiAutomationDriver newUiAutomationDriver(Instrumentation instrumentation) {
     if (!hasUiAutomation()) {
-      throw new DroidDriverException(
-          "http://developer.android.com/reference/android/app/UiAutomation.html" +
-          " is not available below API 18");
+      throw new DroidDriverException("UiAutomation is not available below API 18. "
+          + "See http://developer.android.com/reference/android/app/UiAutomation.html");
     }
     if (instrumentation.getUiAutomation() == null) {
       throw new DroidDriverException(
diff --git a/src/com/google/android/droiddriver/instrumentation/ViewElement.java b/src/com/google/android/droiddriver/instrumentation/ViewElement.java
index e38929a..fd4c39a 100644
--- a/src/com/google/android/droiddriver/instrumentation/ViewElement.java
+++ b/src/com/google/android/droiddriver/instrumentation/ViewElement.java
@@ -26,6 +26,7 @@ import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.Checkable;
 import android.widget.TextView;
 
+import com.google.android.droiddriver.actions.EventUiElementActor;
 import com.google.android.droiddriver.actions.InputInjector;
 import com.google.android.droiddriver.base.BaseUiElement;
 import com.google.android.droiddriver.exceptions.DroidDriverException;
@@ -218,6 +219,7 @@ public class ViewElement extends BaseUiElement {
    * {@link com.google.android.droiddriver.DroidDriver#refreshUiElementTree}.
    */
   public ViewElement(final InstrumentationContext context, View view, ViewElement parent) {
+    super(EventUiElementActor.INSTANCE);
     this.context = Preconditions.checkNotNull(context);
     Preconditions.checkNotNull(view);
     this.parent = parent;
diff --git a/src/com/google/android/droiddriver/runner/TestRunner.java b/src/com/google/android/droiddriver/runner/TestRunner.java
index 8e86a20..e6277fb 100644
--- a/src/com/google/android/droiddriver/runner/TestRunner.java
+++ b/src/com/google/android/droiddriver/runner/TestRunner.java
@@ -66,6 +66,8 @@ public class TestRunner extends InstrumentationTestRunner {
    */
   @Override
   public void onStart() {
+    DroidDrivers.initInstrumentation(this, getArguments());
+
     getAndroidTestRunner().addTestListener(new TestListener() {
       @Override
       public void endTest(Test test) {
diff --git a/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java b/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
index 7929798..6911fa6 100644
--- a/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
+++ b/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
@@ -197,7 +197,7 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
     // We do not call container.scroll(direction) because container.scroll internally calls
     // UiAutomation.executeAndWaitForEvent which clears the AccessibilityEvent Queue, preventing us
     // from fetching the last accessibility event to determine if scrolling has finished.
-    SwipeAction.toScroll(direction).perform(container.getInjector(), container);
+    SwipeAction.toScroll(direction).perform(container);
   }
 
   /**
diff --git a/src/com/google/android/droiddriver/uiautomation/UiAutomationContext.java b/src/com/google/android/droiddriver/uiautomation/UiAutomationContext.java
index fcb7a94..04df113 100644
--- a/src/com/google/android/droiddriver/uiautomation/UiAutomationContext.java
+++ b/src/com/google/android/droiddriver/uiautomation/UiAutomationContext.java
@@ -17,81 +17,17 @@
 package com.google.android.droiddriver.uiautomation;
 
 import android.app.Instrumentation;
-import android.app.UiAutomation;
-import android.view.InputEvent;
 import android.view.accessibility.AccessibilityNodeInfo;
 
-import com.google.android.droiddriver.actions.InputInjector;
-import com.google.android.droiddriver.base.DroidDriverContext;
-import com.google.android.droiddriver.exceptions.UnrecoverableException;
-import com.google.android.droiddriver.finders.ByXPath;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationContext;
 
-import java.util.Map;
-import java.util.WeakHashMap;
-
-class UiAutomationContext extends DroidDriverContext {
-  private final Map<AccessibilityNodeInfo, UiAutomationElement> map =
-      new WeakHashMap<AccessibilityNodeInfo, UiAutomationElement>();
-  private final UiAutomation uiAutomation;
-  private final InputInjector injector;
-  private final UiAutomationDriver driver;
-
-  UiAutomationContext(final Instrumentation instrumentation, UiAutomationDriver driver) {
-    super(instrumentation);
-    this.uiAutomation = instrumentation.getUiAutomation();
-    this.driver = driver;
-    this.injector = new InputInjector() {
-      @Override
-      public boolean injectInputEvent(final InputEvent event) {
-        return callUiAutomation(new UiAutomationCallable<Boolean>() {
-          @Override
-          public Boolean call(UiAutomation uiAutomation) {
-            return uiAutomation.injectInputEvent(event, true /* sync */);
-          }
-        });
-      }
-    };
-  }
-
-  @Override
-  public UiAutomationDriver getDriver() {
-    return driver;
-  }
-
-  @Override
-  public InputInjector getInjector() {
-    return injector;
-  }
-
-  UiAutomationElement getUiElement(AccessibilityNodeInfo node, UiAutomationElement parent) {
-    UiAutomationElement element = map.get(node);
-    if (element == null) {
-      element = new UiAutomationElement(this, node, parent);
-      map.put(node, element);
-    }
-    return element;
+class UiAutomationContext extends BaseUiAutomationContext<UiAutomationElement> {
+  UiAutomationContext(Instrumentation instrumentation, UiAutomationDriver driver) {
+    super(instrumentation, driver);
   }
 
   @Override
-  public void clearData() {
-    map.clear();
-    ByXPath.clearData();
-  }
-
-  interface UiAutomationCallable<T> {
-    T call(UiAutomation uiAutomation);
-  }
-
-  /*
-   * Wraps calls to UiAutomation API. Currently supports fail-fast if
-   * UiAutomation throws IllegalStateException, which occurs when the connection
-   * to UiAutomation service is lost.
-   */
-  <T> T callUiAutomation(UiAutomationCallable<T> uiAutomationCallable) {
-    try {
-      return uiAutomationCallable.call(uiAutomation);
-    } catch (IllegalStateException e) {
-      throw new UnrecoverableException(e);
-    }
+  protected UiAutomationElement newUiElement(AccessibilityNodeInfo node, UiAutomationElement parent) {
+    return new UiAutomationElement(this, node, parent);
   }
 }
diff --git a/src/com/google/android/droiddriver/uiautomation/UiAutomationDriver.java b/src/com/google/android/droiddriver/uiautomation/UiAutomationDriver.java
index d465816..9291f13 100644
--- a/src/com/google/android/droiddriver/uiautomation/UiAutomationDriver.java
+++ b/src/com/google/android/droiddriver/uiautomation/UiAutomationDriver.java
@@ -17,112 +17,20 @@
 package com.google.android.droiddriver.uiautomation;
 
 import android.app.Instrumentation;
-import android.app.UiAutomation;
-import android.content.Context;
-import android.os.SystemClock;
-import android.view.accessibility.AccessibilityEvent;
-import android.view.accessibility.AccessibilityManager;
-import android.view.accessibility.AccessibilityNodeInfo;
 
-import com.google.android.droiddriver.base.BaseDroidDriver;
-import com.google.android.droiddriver.exceptions.TimeoutException;
-import com.google.android.droiddriver.uiautomation.UiAutomationContext.UiAutomationCallable;
-import com.google.android.droiddriver.util.Logs;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationDriver;
 
 /**
- * Implementation of DroidDriver that is driven via the accessibility layer.
+ * Implementation of DroidDriver that gets attributes via the Accessibility API
+ * and is acted upon via synthesized events.
  */
-public class UiAutomationDriver extends BaseDroidDriver {
-  // TODO: magic const from UiAutomator, but may not be useful
-  /**
-   * This value has the greatest bearing on the appearance of test execution
-   * speeds. This value is used as the minimum time to wait before considering
-   * the UI idle after each action.
-   */
-  private static final long QUIET_TIME_TO_BE_CONSIDERD_IDLE_STATE = 500;// ms
-
-  private final UiAutomationContext context;
-  private final UiAutomationUiDevice uiDevice;
-
+public class UiAutomationDriver extends BaseUiAutomationDriver<UiAutomationElement> {
   public UiAutomationDriver(Instrumentation instrumentation) {
-    this.context = new UiAutomationContext(instrumentation, this);
-    this.uiDevice = new UiAutomationUiDevice(context);
-  }
-
-  @Override
-  protected UiAutomationElement getNewRootElement() {
-    return context.getUiElement(getRootNode(), null /* parent */);
-  }
-
-  @Override
-  protected UiAutomationContext getContext() {
-    return context;
-  }
-
-  private AccessibilityNodeInfo getRootNode() {
-    final long timeoutMillis = getPoller().getTimeoutMillis();
-    context.callUiAutomation(new UiAutomationCallable<Void>() {
-      @Override
-      public Void call(UiAutomation uiAutomation) {
-        try {
-          uiAutomation.waitForIdle(QUIET_TIME_TO_BE_CONSIDERD_IDLE_STATE, timeoutMillis);
-          return null;
-        } catch (java.util.concurrent.TimeoutException e) {
-          throw new TimeoutException(e);
-        }
-      }
-    });
-
-    long end = SystemClock.uptimeMillis() + timeoutMillis;
-    while (true) {
-      AccessibilityNodeInfo root =
-          context.callUiAutomation(new UiAutomationCallable<AccessibilityNodeInfo>() {
-            @Override
-            public AccessibilityNodeInfo call(UiAutomation uiAutomation) {
-              return uiAutomation.getRootInActiveWindow();
-            }
-          });
-      if (root != null) {
-        return root;
-      }
-      long remainingMillis = end - SystemClock.uptimeMillis();
-      if (remainingMillis < 0) {
-        throw new TimeoutException(
-            String.format("Timed out after %d milliseconds waiting for root AccessibilityNodeInfo",
-                timeoutMillis));
-      }
-      SystemClock.sleep(Math.min(250, remainingMillis));
-    }
-  }
-
-  /**
-   * Some widgets fail to trigger some AccessibilityEvent's after actions,
-   * resulting in stale AccessibilityNodeInfo's. As a work-around, force to
-   * clear the AccessibilityNodeInfoCache.
-   */
-  public void clearAccessibilityNodeInfoCache() {
-    Logs.call(this, "clearAccessibilityNodeInfoCache");
-    uiDevice.sleep();
-    uiDevice.wakeUp();
-  }
-
-  /**
-   * {@link #clearAccessibilityNodeInfoCache} causes the screen to blink. This
-   * method clears the cache without blinking by employing an implementation
-   * detail of AccessibilityNodeInfoCache. This is a hack; use it at your own
-   * discretion.
-   */
-  public void clearAccessibilityNodeInfoCacheHack() {
-    Logs.call(this, "clearAccessibilityNodeInfoCacheHack");
-    AccessibilityManager accessibilityManager =
-        (AccessibilityManager) context.getInstrumentation().getTargetContext()
-            .getSystemService(Context.ACCESSIBILITY_SERVICE);
-    accessibilityManager.sendAccessibilityEvent(AccessibilityEvent
-        .obtain(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED));
+    super(instrumentation);
   }
 
   @Override
-  public UiAutomationUiDevice getUiDevice() {
-    return uiDevice;
+  protected UiAutomationContext newContext(Instrumentation instrumentation) {
+    return new UiAutomationContext(instrumentation, this);
   }
 }
diff --git a/src/com/google/android/droiddriver/uiautomation/UiAutomationElement.java b/src/com/google/android/droiddriver/uiautomation/UiAutomationElement.java
index 5d69814..9a4309b 100644
--- a/src/com/google/android/droiddriver/uiautomation/UiAutomationElement.java
+++ b/src/com/google/android/droiddriver/uiautomation/UiAutomationElement.java
@@ -16,193 +16,17 @@
 
 package com.google.android.droiddriver.uiautomation;
 
-import static com.google.android.droiddriver.util.Strings.charSequenceToString;
-
-import android.app.UiAutomation;
-import android.app.UiAutomation.AccessibilityEventFilter;
-import android.graphics.Rect;
-import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityNodeInfo;
 
-import com.google.android.droiddriver.actions.InputInjector;
-import com.google.android.droiddriver.base.BaseUiElement;
-import com.google.android.droiddriver.finders.Attribute;
-import com.google.android.droiddriver.uiautomation.UiAutomationContext.UiAutomationCallable;
-import com.google.android.droiddriver.util.Preconditions;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.EnumMap;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.FutureTask;
-import java.util.concurrent.TimeoutException;
+import com.google.android.droiddriver.actions.EventUiElementActor;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationElement;
 
 /**
- * A UiElement that is backed by an {@link AccessibilityNodeInfo}.
+ * A BaseUiAutomationElement that is acted upon via synthesized events.
  */
-public class UiAutomationElement extends BaseUiElement {
-  private static final AccessibilityEventFilter ANY_EVENT_FILTER = new AccessibilityEventFilter() {
-    @Override
-    public boolean accept(AccessibilityEvent arg0) {
-      return true;
-    }
-  };
-
-  private final UiAutomationContext context;
-  private final Map<Attribute, Object> attributes;
-  private final boolean visible;
-  private final Rect visibleBounds;
-  private final UiAutomationElement parent;
-  private final List<UiAutomationElement> children;
-
-  /**
-   * A snapshot of all attributes is taken at construction. The attributes of a
-   * {@code UiAutomationElement} instance are immutable. If the underlying
-   * {@link AccessibilityNodeInfo} is updated, a new {@code UiAutomationElement}
-   * instance will be created in
-   * {@link com.google.android.droiddriver.DroidDriver#refreshUiElementTree}.
-   */
-  public UiAutomationElement(UiAutomationContext context, AccessibilityNodeInfo node,
+class UiAutomationElement extends BaseUiAutomationElement<UiAutomationElement> {
+  UiAutomationElement(UiAutomationContext context, AccessibilityNodeInfo node,
       UiAutomationElement parent) {
-    this.context = Preconditions.checkNotNull(context);
-    Preconditions.checkNotNull(node);
-    this.parent = parent;
-
-    Map<Attribute, Object> attribs = new EnumMap<Attribute, Object>(Attribute.class);
-    put(attribs, Attribute.PACKAGE, charSequenceToString(node.getPackageName()));
-    put(attribs, Attribute.CLASS, charSequenceToString(node.getClassName()));
-    put(attribs, Attribute.TEXT, charSequenceToString(node.getText()));
-    put(attribs, Attribute.CONTENT_DESC, charSequenceToString(node.getContentDescription()));
-    put(attribs, Attribute.RESOURCE_ID, charSequenceToString(node.getViewIdResourceName()));
-    put(attribs, Attribute.CHECKABLE, node.isCheckable());
-    put(attribs, Attribute.CHECKED, node.isChecked());
-    put(attribs, Attribute.CLICKABLE, node.isClickable());
-    put(attribs, Attribute.ENABLED, node.isEnabled());
-    put(attribs, Attribute.FOCUSABLE, node.isFocusable());
-    put(attribs, Attribute.FOCUSED, node.isFocused());
-    put(attribs, Attribute.LONG_CLICKABLE, node.isLongClickable());
-    put(attribs, Attribute.PASSWORD, node.isPassword());
-    put(attribs, Attribute.SCROLLABLE, node.isScrollable());
-    if (node.getTextSelectionStart() >= 0
-        && node.getTextSelectionStart() != node.getTextSelectionEnd()) {
-      attribs.put(Attribute.SELECTION_START, node.getTextSelectionStart());
-      attribs.put(Attribute.SELECTION_END, node.getTextSelectionEnd());
-    }
-    put(attribs, Attribute.SELECTED, node.isSelected());
-    put(attribs, Attribute.BOUNDS, getBounds(node));
-    attributes = Collections.unmodifiableMap(attribs);
-
-    // Order matters as getVisibleBounds depends on visible
-    visible = node.isVisibleToUser();
-    visibleBounds = getVisibleBounds(node);
-    List<UiAutomationElement> mutableChildren = buildChildren(context, node);
-    this.children = mutableChildren == null ? null : Collections.unmodifiableList(mutableChildren);
-  }
-
-  private void put(Map<Attribute, Object> attribs, Attribute key, Object value) {
-    if (value != null) {
-      attribs.put(key, value);
-    }
-  }
-
-  private List<UiAutomationElement> buildChildren(UiAutomationContext context,
-      AccessibilityNodeInfo node) {
-    List<UiAutomationElement> children;
-    int childCount = node.getChildCount();
-    if (childCount == 0) {
-      children = null;
-    } else {
-      children = new ArrayList<UiAutomationElement>(childCount);
-      for (int i = 0; i < childCount; i++) {
-        AccessibilityNodeInfo child = node.getChild(i);
-        if (child != null) {
-          children.add(context.getUiElement(child, this));
-        }
-      }
-    }
-    return children;
-  }
-
-  private Rect getBounds(AccessibilityNodeInfo node) {
-    Rect rect = new Rect();
-    node.getBoundsInScreen(rect);
-    return rect;
-  }
-
-  private Rect getVisibleBounds(AccessibilityNodeInfo node) {
-    if (!visible) {
-      return new Rect();
-    }
-    Rect visibleBounds = getBounds();
-    UiAutomationElement parent = getParent();
-    Rect parentBounds;
-    while (parent != null) {
-      parentBounds = parent.getBounds();
-      visibleBounds.intersect(parentBounds);
-      parent = parent.getParent();
-    }
-    return visibleBounds;
-  }
-
-  @Override
-  public Rect getVisibleBounds() {
-    return visibleBounds;
-  }
-
-  @Override
-  public boolean isVisible() {
-    return visible;
-  }
-
-  @Override
-  public UiAutomationElement getParent() {
-    return parent;
-  }
-
-  @Override
-  protected List<UiAutomationElement> getChildren() {
-    return children;
-  }
-
-  @Override
-  protected Map<Attribute, Object> getAttributes() {
-    return attributes;
-  }
-
-  @Override
-  public InputInjector getInjector() {
-    return context.getInjector();
-  }
-
-  /**
-   * Note: The {@code UiAutomationElement} implementation of {@code doPerformAndWait} clears the
-   * {@code AccessibilityEvent} queue.
-   */
-  @Override
-  protected void doPerformAndWait(final FutureTask<Boolean> futureTask, final long timeoutMillis) {
-    context.callUiAutomation(new UiAutomationCallable<Void>() {
-
-      @Override
-      public Void call(UiAutomation uiAutomation) {
-        try {
-          uiAutomation.executeAndWaitForEvent(futureTask, ANY_EVENT_FILTER, timeoutMillis);
-        } catch (TimeoutException e) {
-          // This is for sync'ing with Accessibility API on best-effort because
-          // it is not reliable.
-          // Exception is ignored here. Tests will fail anyways if this is
-          // critical.
-          // Actions should usually trigger some AccessibilityEvent's, but some
-          // widgets fail to do so, resulting in stale AccessibilityNodeInfo's.
-          // As a work-around, force to clear the AccessibilityNodeInfoCache.
-          // A legitimate case of no AccessibilityEvent is when scrolling has
-          // reached the end, but we cannot tell whether it's legitimate or the
-          // widget has bugs, so clearAccessibilityNodeInfoCache anyways.
-          context.getDriver().clearAccessibilityNodeInfoCacheHack();
-        }
-        return null;
-      }
-
-    });
+    super(context, node, parent, EventUiElementActor.INSTANCE);
   }
 }
diff --git a/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityContext.java b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityContext.java
new file mode 100644
index 0000000..4c76d29
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityContext.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.accessibility;
+
+import android.app.Instrumentation;
+import android.view.InputEvent;
+import android.view.MotionEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.actions.InputInjector;
+import com.google.android.droiddriver.exceptions.DroidDriverException;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationContext;
+import com.google.android.droiddriver.uiautomation.base.UiAutomationInputInjector;
+
+class AccessibilityContext extends BaseUiAutomationContext<AccessibilityElement> {
+  AccessibilityContext(Instrumentation instrumentation, AccessibilityDriver driver) {
+    super(instrumentation, driver);
+  }
+
+  @Override
+  protected InputInjector newInputInjector() {
+    return new UiAutomationInputInjector(this) {
+      @Override
+      public boolean injectInputEvent(InputEvent event) {
+        if (event instanceof MotionEvent) {
+          throw new DroidDriverException(
+              "AccessibilityDriver forbids MotionEvent in order to detect accessibility issues");
+        }
+        return super.injectInputEvent(event);
+      }
+    };
+  }
+
+  @Override
+  protected AccessibilityElement newUiElement(AccessibilityNodeInfo node,
+      AccessibilityElement parent) {
+    return new AccessibilityElement(this, node, parent);
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityDriver.java b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityDriver.java
new file mode 100644
index 0000000..2f2295c
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityDriver.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.accessibility;
+
+import android.app.Instrumentation;
+
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationDriver;
+
+/**
+ * Implementation of DroidDriver that gets attributes via the Accessibility API
+ * and is acted upon via the Accessibility API.
+ */
+public class AccessibilityDriver extends BaseUiAutomationDriver<AccessibilityElement> {
+  public AccessibilityDriver(Instrumentation instrumentation) {
+    super(instrumentation);
+  }
+
+  @Override
+  protected AccessibilityContext newContext(Instrumentation instrumentation) {
+    return new AccessibilityContext(instrumentation, this);
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityElement.java b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityElement.java
new file mode 100644
index 0000000..c208730
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/accessibility/AccessibilityElement.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.accessibility;
+
+import android.text.TextUtils;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.actions.Action;
+import com.google.android.droiddriver.actions.accessibility.AccessibilityUiElementActor;
+import com.google.android.droiddriver.exceptions.DroidDriverException;
+import com.google.android.droiddriver.uiautomation.base.BaseUiAutomationElement;
+
+/**
+ * A UiElement that gets attributes via the Accessibility API and is acted upon
+ * via the Accessibility API.
+ */
+class AccessibilityElement extends BaseUiAutomationElement<AccessibilityElement> {
+  AccessibilityElement(AccessibilityContext context, AccessibilityNodeInfo node,
+      AccessibilityElement parent) {
+    super(context, node, parent, AccessibilityUiElementActor.INSTANCE);
+  }
+
+  @Override
+  public boolean perform(Action action) {
+    checkAccessible();
+    return super.perform(action);
+  }
+
+  private void checkAccessible() {
+    if (getParent() != null // don't check root
+        && TextUtils.isEmpty(this.getContentDescription()) && TextUtils.isEmpty(this.getText())) {
+      throw new DroidDriverException(
+          "Accessibility issue: either content description or text must be set for actionable"
+              + " user interface controls");
+    }
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationContext.java b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationContext.java
new file mode 100644
index 0000000..1412818
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationContext.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.base;
+
+import android.app.Instrumentation;
+import android.app.UiAutomation;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.actions.InputInjector;
+import com.google.android.droiddriver.base.DroidDriverContext;
+import com.google.android.droiddriver.exceptions.UnrecoverableException;
+import com.google.android.droiddriver.finders.ByXPath;
+
+import java.util.Map;
+import java.util.WeakHashMap;
+
+public abstract class BaseUiAutomationContext<E extends BaseUiAutomationElement<E>> extends
+    DroidDriverContext {
+  private final UiAutomation uiAutomation;
+  private final BaseUiAutomationDriver<E> driver;
+  private final InputInjector injector;
+  private final Map<AccessibilityNodeInfo, E> map;
+
+  protected BaseUiAutomationContext(Instrumentation instrumentation,
+      BaseUiAutomationDriver<E> driver) {
+    super(instrumentation);
+    this.uiAutomation = instrumentation.getUiAutomation();
+    this.driver = driver;
+    this.map = new WeakHashMap<AccessibilityNodeInfo, E>();
+    injector = newInputInjector();
+  }
+
+  /**
+   * Subclasses can override to return a different InputInjector, for example,
+   * forbidding MotionEvent in order to detect accessibility issues.
+   */
+  protected InputInjector newInputInjector() {
+    return new UiAutomationInputInjector(this);
+  }
+
+  /**
+   * Returns a new UiElement of type {@code E}.
+   */
+  protected abstract E newUiElement(AccessibilityNodeInfo node, E parent);
+
+  @Override
+  public BaseUiAutomationDriver<E> getDriver() {
+    return driver;
+  }
+
+  @Override
+  public InputInjector getInjector() {
+    return injector;
+  }
+
+  E getUiElement(AccessibilityNodeInfo node, E parent) {
+    E element = map.get(node);
+    if (element == null) {
+      element = newUiElement(node, parent);
+      map.put(node, element);
+    }
+    return element;
+  }
+
+  @Override
+  public void clearData() {
+    map.clear();
+    ByXPath.clearData();
+  }
+
+  /**
+   * Wraps calls to UiAutomation API. Currently supports fail-fast if
+   * UiAutomation throws IllegalStateException, which occurs when the connection
+   * to UiAutomation service is lost.
+   */
+  public <T> T callUiAutomation(UiAutomationCallable<T> uiAutomationCallable) {
+    try {
+      return uiAutomationCallable.call(uiAutomation);
+    } catch (IllegalStateException e) {
+      throw new UnrecoverableException(e);
+    }
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationDriver.java b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationDriver.java
new file mode 100644
index 0000000..fe223e3
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationDriver.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.base;
+
+import android.app.Instrumentation;
+import android.app.UiAutomation;
+import android.content.Context;
+import android.os.SystemClock;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.base.BaseDroidDriver;
+import com.google.android.droiddriver.exceptions.TimeoutException;
+import com.google.android.droiddriver.util.Logs;
+
+/**
+ * Base implementation of DroidDriver that gets attributes via the Accessibility
+ * API.
+ */
+public abstract class BaseUiAutomationDriver<E extends BaseUiAutomationElement<E>> extends
+    BaseDroidDriver {
+  // TODO: magic const from UiAutomator, but may not be useful
+  /**
+   * This value has the greatest bearing on the appearance of test execution
+   * speeds. This value is used as the minimum time to wait before considering
+   * the UI idle after each action.
+   */
+  private static final long QUIET_TIME_TO_BE_CONSIDERD_IDLE_STATE = 500;// ms
+
+  private final BaseUiAutomationContext<E> context;
+  private final UiAutomationUiDevice uiDevice;
+
+  protected BaseUiAutomationDriver(Instrumentation instrumentation) {
+    this.context = newContext(instrumentation);
+    this.uiDevice = new UiAutomationUiDevice(context);
+  }
+
+  protected abstract BaseUiAutomationContext<E> newContext(Instrumentation instrumentation);
+
+  @Override
+  protected E getNewRootElement() {
+    return context.getUiElement(getRootNode(), null /* parent */);
+  }
+
+  @Override
+  protected BaseUiAutomationContext<E> getContext() {
+    return context;
+  }
+
+  private AccessibilityNodeInfo getRootNode() {
+    final long timeoutMillis = getPoller().getTimeoutMillis();
+    context.callUiAutomation(new UiAutomationCallable<Void>() {
+      @Override
+      public Void call(UiAutomation uiAutomation) {
+        try {
+          uiAutomation.waitForIdle(QUIET_TIME_TO_BE_CONSIDERD_IDLE_STATE, timeoutMillis);
+          return null;
+        } catch (java.util.concurrent.TimeoutException e) {
+          throw new TimeoutException(e);
+        }
+      }
+    });
+
+    long end = SystemClock.uptimeMillis() + timeoutMillis;
+    while (true) {
+      AccessibilityNodeInfo root =
+          context.callUiAutomation(new UiAutomationCallable<AccessibilityNodeInfo>() {
+            @Override
+            public AccessibilityNodeInfo call(UiAutomation uiAutomation) {
+              return uiAutomation.getRootInActiveWindow();
+            }
+          });
+      if (root != null) {
+        return root;
+      }
+      long remainingMillis = end - SystemClock.uptimeMillis();
+      if (remainingMillis < 0) {
+        throw new TimeoutException(
+            String.format("Timed out after %d milliseconds waiting for root AccessibilityNodeInfo",
+                timeoutMillis));
+      }
+      SystemClock.sleep(Math.min(250, remainingMillis));
+    }
+  }
+
+  /**
+   * Some widgets fail to trigger some AccessibilityEvent's after actions,
+   * resulting in stale AccessibilityNodeInfo's. As a work-around, force to
+   * clear the AccessibilityNodeInfoCache.
+   */
+  public void clearAccessibilityNodeInfoCache() {
+    Logs.call(this, "clearAccessibilityNodeInfoCache");
+    uiDevice.sleep();
+    uiDevice.wakeUp();
+  }
+
+  /**
+   * {@link #clearAccessibilityNodeInfoCache} causes the screen to blink. This
+   * method clears the cache without blinking by employing an implementation
+   * detail of AccessibilityNodeInfoCache. This is a hack; use it at your own
+   * discretion.
+   */
+  public void clearAccessibilityNodeInfoCacheHack() {
+    Logs.call(this, "clearAccessibilityNodeInfoCacheHack");
+    AccessibilityManager accessibilityManager =
+        (AccessibilityManager) context.getInstrumentation().getTargetContext()
+            .getSystemService(Context.ACCESSIBILITY_SERVICE);
+    accessibilityManager.sendAccessibilityEvent(AccessibilityEvent
+        .obtain(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED));
+  }
+
+  @Override
+  public UiAutomationUiDevice getUiDevice() {
+    return uiDevice;
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationElement.java b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationElement.java
new file mode 100644
index 0000000..a27a3eb
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/base/BaseUiAutomationElement.java
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.base;
+
+import static com.google.android.droiddriver.util.Strings.charSequenceToString;
+
+import android.app.UiAutomation;
+import android.app.UiAutomation.AccessibilityEventFilter;
+import android.graphics.Rect;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import com.google.android.droiddriver.actions.InputInjector;
+import com.google.android.droiddriver.base.BaseUiElement;
+import com.google.android.droiddriver.base.UiElementActor;
+import com.google.android.droiddriver.finders.Attribute;
+import com.google.android.droiddriver.util.Preconditions;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * A UiElement that gets attributes via the Accessibility API.
+ */
+public class BaseUiAutomationElement<E extends BaseUiAutomationElement<E>> extends BaseUiElement {
+  private static final AccessibilityEventFilter ANY_EVENT_FILTER = new AccessibilityEventFilter() {
+    @Override
+    public boolean accept(AccessibilityEvent arg0) {
+      return true;
+    }
+  };
+
+  private final AccessibilityNodeInfo node;
+  private final BaseUiAutomationContext<E> context;
+  private final Map<Attribute, Object> attributes;
+  private final boolean visible;
+  private final Rect visibleBounds;
+  private final E parent;
+  private final List<E> children;
+
+  /**
+   * A snapshot of all attributes is taken at construction. The attributes of a
+   * {@code UiAutomationElement} instance are immutable. If the underlying
+   * {@link AccessibilityNodeInfo} is updated, a new {@code UiAutomationElement}
+   * instance will be created in
+   * {@link com.google.android.droiddriver.DroidDriver#refreshUiElementTree}.
+   */
+  protected BaseUiAutomationElement(BaseUiAutomationContext<E> context, AccessibilityNodeInfo node,
+      E parent, UiElementActor UiElementActor) {
+    super(UiElementActor);
+    this.node = Preconditions.checkNotNull(node);
+    this.context = Preconditions.checkNotNull(context);
+    this.parent = parent;
+
+    Map<Attribute, Object> attribs = new EnumMap<Attribute, Object>(Attribute.class);
+    put(attribs, Attribute.PACKAGE, charSequenceToString(node.getPackageName()));
+    put(attribs, Attribute.CLASS, charSequenceToString(node.getClassName()));
+    put(attribs, Attribute.TEXT, charSequenceToString(node.getText()));
+    put(attribs, Attribute.CONTENT_DESC, charSequenceToString(node.getContentDescription()));
+    put(attribs, Attribute.RESOURCE_ID, charSequenceToString(node.getViewIdResourceName()));
+    put(attribs, Attribute.CHECKABLE, node.isCheckable());
+    put(attribs, Attribute.CHECKED, node.isChecked());
+    put(attribs, Attribute.CLICKABLE, node.isClickable());
+    put(attribs, Attribute.ENABLED, node.isEnabled());
+    put(attribs, Attribute.FOCUSABLE, node.isFocusable());
+    put(attribs, Attribute.FOCUSED, node.isFocused());
+    put(attribs, Attribute.LONG_CLICKABLE, node.isLongClickable());
+    put(attribs, Attribute.PASSWORD, node.isPassword());
+    put(attribs, Attribute.SCROLLABLE, node.isScrollable());
+    if (node.getTextSelectionStart() >= 0
+        && node.getTextSelectionStart() != node.getTextSelectionEnd()) {
+      attribs.put(Attribute.SELECTION_START, node.getTextSelectionStart());
+      attribs.put(Attribute.SELECTION_END, node.getTextSelectionEnd());
+    }
+    put(attribs, Attribute.SELECTED, node.isSelected());
+    put(attribs, Attribute.BOUNDS, getBounds(node));
+    attributes = Collections.unmodifiableMap(attribs);
+
+    // Order matters as getVisibleBounds depends on visible
+    visible = node.isVisibleToUser();
+    visibleBounds = getVisibleBounds(node);
+    List<E> mutableChildren = buildChildren(node);
+    this.children = mutableChildren == null ? null : Collections.unmodifiableList(mutableChildren);
+  }
+
+  private void put(Map<Attribute, Object> attribs, Attribute key, Object value) {
+    if (value != null) {
+      attribs.put(key, value);
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private List<E> buildChildren(AccessibilityNodeInfo node) {
+    List<E> children;
+    int childCount = node.getChildCount();
+    if (childCount == 0) {
+      children = null;
+    } else {
+      children = new ArrayList<E>(childCount);
+      for (int i = 0; i < childCount; i++) {
+        AccessibilityNodeInfo child = node.getChild(i);
+        if (child != null) {
+          children.add(context.getUiElement(child, (E) this));
+        }
+      }
+    }
+    return children;
+  }
+
+  private Rect getBounds(AccessibilityNodeInfo node) {
+    Rect rect = new Rect();
+    node.getBoundsInScreen(rect);
+    return rect;
+  }
+
+  private Rect getVisibleBounds(AccessibilityNodeInfo node) {
+    if (!visible) {
+      return new Rect();
+    }
+    Rect visibleBounds = getBounds();
+    E parent = getParent();
+    Rect parentBounds;
+    while (parent != null) {
+      parentBounds = parent.getBounds();
+      visibleBounds.intersect(parentBounds);
+      parent = parent.getParent();
+    }
+    return visibleBounds;
+  }
+
+  @Override
+  public Rect getVisibleBounds() {
+    return visibleBounds;
+  }
+
+  @Override
+  public boolean isVisible() {
+    return visible;
+  }
+
+  @Override
+  public E getParent() {
+    return parent;
+  }
+
+  @Override
+  protected List<E> getChildren() {
+    return children;
+  }
+
+  @Override
+  protected Map<Attribute, Object> getAttributes() {
+    return attributes;
+  }
+
+  @Override
+  public InputInjector getInjector() {
+    return context.getInjector();
+  }
+
+  /**
+   * Note: This implementation of {@code doPerformAndWait} clears the
+   * {@code AccessibilityEvent} queue.
+   */
+  @Override
+  protected void doPerformAndWait(final FutureTask<Boolean> futureTask, final long timeoutMillis) {
+    context.callUiAutomation(new UiAutomationCallable<Void>() {
+
+      @Override
+      public Void call(UiAutomation uiAutomation) {
+        try {
+          uiAutomation.executeAndWaitForEvent(futureTask, ANY_EVENT_FILTER, timeoutMillis);
+        } catch (TimeoutException e) {
+          // This is for sync'ing with Accessibility API on best-effort because
+          // it is not reliable.
+          // Exception is ignored here. Tests will fail anyways if this is
+          // critical.
+          // Actions should usually trigger some AccessibilityEvent's, but some
+          // widgets fail to do so, resulting in stale AccessibilityNodeInfo's.
+          // As a work-around, force to clear the AccessibilityNodeInfoCache.
+          // A legitimate case of no AccessibilityEvent is when scrolling has
+          // reached the end, but we cannot tell whether it's legitimate or the
+          // widget has bugs, so clearAccessibilityNodeInfoCache anyways.
+          context.getDriver().clearAccessibilityNodeInfoCacheHack();
+        }
+        return null;
+      }
+
+    });
+  }
+
+  /**
+   * Gets the AccessibilityNodeInfo used to create this UiElement. The
+   * attributes of this UiElement are based on a snapshot of the
+   * AccessibilityNodeInfo at construction time. If the Accessibility framework
+   * updated it later, the attributes may not match.
+   */
+  public AccessibilityNodeInfo getNode() {
+    return node;
+  }
+}
diff --git a/src/com/google/android/droiddriver/actions/ScrollAction.java b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationCallable.java
index e616e09..36a5292 100644
--- a/src/com/google/android/droiddriver/actions/ScrollAction.java
+++ b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationCallable.java
@@ -14,13 +14,10 @@
  * limitations under the License.
  */
 
-package com.google.android.droiddriver.actions;
+package com.google.android.droiddriver.uiautomation.base;
 
-/**
- * Base class for {@link Action} that scrolls.
- */
-public abstract class ScrollAction extends BaseAction {
-  protected ScrollAction(long timeoutMillis) {
-    super(timeoutMillis);
-  }
-}
+import android.app.UiAutomation;
+
+public interface UiAutomationCallable<T> {
+  T call(UiAutomation uiAutomation);
+}
\ No newline at end of file
diff --git a/src/com/google/android/droiddriver/uiautomation/base/UiAutomationInputInjector.java b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationInputInjector.java
new file mode 100644
index 0000000..5d13d2d
--- /dev/null
+++ b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationInputInjector.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2013 DroidDriver committers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.droiddriver.uiautomation.base;
+
+import android.app.UiAutomation;
+import android.view.InputEvent;
+
+import com.google.android.droiddriver.actions.InputInjector;
+
+public class UiAutomationInputInjector implements InputInjector {
+  private final BaseUiAutomationContext<?> context;
+
+  public UiAutomationInputInjector(BaseUiAutomationContext<?> context) {
+    this.context = context;
+  }
+
+  @Override
+  public boolean injectInputEvent(final InputEvent event) {
+    return context.callUiAutomation(new UiAutomationCallable<Boolean>() {
+      @Override
+      public Boolean call(UiAutomation uiAutomation) {
+        return uiAutomation.injectInputEvent(event, true /* sync */);
+      }
+    });
+  }
+}
diff --git a/src/com/google/android/droiddriver/uiautomation/UiAutomationUiDevice.java b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationUiDevice.java
index a376cb6..5c66ef5 100644
--- a/src/com/google/android/droiddriver/uiautomation/UiAutomationUiDevice.java
+++ b/src/com/google/android/droiddriver/uiautomation/base/UiAutomationUiDevice.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.google.android.droiddriver.uiautomation;
+package com.google.android.droiddriver.uiautomation.base;
 
 import android.app.UiAutomation;
 import android.graphics.Bitmap;
@@ -22,13 +22,12 @@ import android.util.Log;
 
 import com.google.android.droiddriver.base.BaseUiDevice;
 import com.google.android.droiddriver.exceptions.UnrecoverableException;
-import com.google.android.droiddriver.uiautomation.UiAutomationContext.UiAutomationCallable;
 import com.google.android.droiddriver.util.Logs;
 
 class UiAutomationUiDevice extends BaseUiDevice {
-  private final UiAutomationContext context;
+  private final BaseUiAutomationContext<?> context;
 
-  UiAutomationUiDevice(UiAutomationContext context) {
+  UiAutomationUiDevice(BaseUiAutomationContext<?> context) {
     this.context = context;
   }
 
@@ -50,7 +49,7 @@ class UiAutomationUiDevice extends BaseUiDevice {
   }
 
   @Override
-  protected UiAutomationContext getContext() {
+  protected BaseUiAutomationContext<?> getContext() {
     return context;
   }
 }