add two new scroll APIs

ForwardingScrollStepStrategy and NullAccessibilityEventScrollStepStrategy

Change-Id: I16efb179f35d3fc178801c596a1d896c8b1e7644

3 files changed, 135 insertions, 12 deletions

diff --git a/src/com/google/android/droiddriver/helpers/PollingListeners.java b/src/com/google/android/droiddriver/helpers/PollingListeners.java
index 2180264..44cd826 100644
--- a/src/com/google/android/droiddriver/helpers/PollingListeners.java
+++ b/src/com/google/android/droiddriver/helpers/PollingListeners.java
@@ -2,6 +2,7 @@ package com.google.android.droiddriver.helpers;
 
 import com.google.android.droiddriver.DroidDriver;
 import com.google.android.droiddriver.Poller.PollingListener;
+import com.google.android.droiddriver.exceptions.ElementNotFoundException;
 import com.google.android.droiddriver.finders.Finder;
 
 /**
@@ -15,11 +16,12 @@ public class PollingListeners {
    * @return whether {@code watchFinder} is found
    */
   public static boolean tryFindAndClick(DroidDriver driver, Finder watchFinder) {
-    if (driver.has(watchFinder)) {
+    try {
       driver.find(watchFinder).click();
       return true;
+    } catch (ElementNotFoundException enfe) {
+      return false;
     }
-    return false;
   }
 
   /**
diff --git a/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java b/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
index 5e3d766..5b8f0f3 100644
--- a/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
+++ b/src/com/google/android/droiddriver/scroll/AccessibilityEventScrollStepStrategy.java
@@ -68,8 +68,8 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
   }
 
   /**
-   * This filter allows us to grab the last accessibility event generated
-   * for a scroll up to {@code scrollEventTimeoutMillis}.
+   * This filter allows us to grab the last accessibility event generated for a
+   * scroll up to {@code scrollEventTimeoutMillis}.
    */
   private static class LastScrollEventFilter implements AccessibilityEventFilter {
     private AccessibilityEvent lastEvent;
@@ -83,7 +83,8 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
         }
         lastEvent = AccessibilityEvent.obtain(event);
       }
-      // Return false to collect events until scrollEventTimeoutMillis has elapsed.
+      // Return false to collect events until scrollEventTimeoutMillis has
+      // elapsed.
       return false;
     }
 
@@ -134,17 +135,21 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
     if (event == null) {
       return true;
     }
-    boolean foundEnd = false;
+
     if (event.getFromIndex() != -1 && event.getToIndex() != -1 && event.getItemCount() != -1) {
-      foundEnd = event.getFromIndex() == 0 || (event.getItemCount() - 1) == event.getToIndex();
-    } else if (event.getScrollX() != -1 && event.getScrollY() != -1) {
+      return event.getFromIndex() == 0 || (event.getItemCount() - 1) == event.getToIndex();
+    }
+    if (event.getScrollX() != -1 && event.getScrollY() != -1) {
       if (axis == Axis.VERTICAL) {
-        foundEnd = event.getScrollY() == 0 || event.getScrollY() == event.getMaxScrollY();
+        return event.getScrollY() == 0 || event.getScrollY() == event.getMaxScrollY();
       } else if (axis == Axis.HORIZONTAL) {
-        foundEnd = event.getScrollX() == 0 || event.getScrollX() == event.getMaxScrollX();
+        return event.getScrollX() == 0 || event.getScrollX() == event.getMaxScrollX();
       }
     }
-    return foundEnd;
+
+    // This case is different from UiAutomator.
+    return event.getFromIndex() == -1 && event.getToIndex() == -1 && event.getItemCount() == -1
+        && event.getScrollX() == -1 && event.getScrollY() == -1;
   }
 
   @Override
@@ -181,7 +186,8 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
     } catch (IllegalStateException e) {
       throw new UnrecoverableException(e);
     } catch (TimeoutException e) {
-      // We expect this because LastScrollEventFilter.accept always returns false.
+      // We expect this because LastScrollEventFilter.accept always returns
+      // false.
     }
     return filter.getLastEvent();
   }
@@ -190,4 +196,23 @@ public class AccessibilityEventScrollStepStrategy implements ScrollStepStrategy
   public void doScroll(final UiElement container, final PhysicalDirection direction) {
     SwipeAction.toScroll(direction).perform(container.getInjector(), container);
   }
+
+  /**
+   * Some widgets may not always fire correct {@link AccessibilityEvent}.
+   * Detecting end by null event is safer (at the cost of a extra scroll) than
+   * examining indices.
+   */
+  public static class NullAccessibilityEventScrollStepStrategy extends
+      AccessibilityEventScrollStepStrategy {
+
+    public NullAccessibilityEventScrollStepStrategy(UiAutomation uiAutomation,
+        long scrollEventTimeoutMillis, DirectionConverter converter) {
+      super(uiAutomation, scrollEventTimeoutMillis, converter);
+    }
+
+    @Override
+    protected boolean detectEnd(AccessibilityEvent event, Axis axis) {
+      return event == null;
+    }
+  }
 }
diff --git a/src/com/google/android/droiddriver/scroll/ForwardingScrollStepStrategy.java b/src/com/google/android/droiddriver/scroll/ForwardingScrollStepStrategy.java
new file mode 100644
index 0000000..7c849a5
--- /dev/null
+++ b/src/com/google/android/droiddriver/scroll/ForwardingScrollStepStrategy.java
@@ -0,0 +1,96 @@
+/*
+ * 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.scroll;
+
+import android.widget.ProgressBar;
+
+import com.google.android.droiddriver.DroidDriver;
+import com.google.android.droiddriver.UiElement;
+import com.google.android.droiddriver.finders.By;
+import com.google.android.droiddriver.finders.Finder;
+import com.google.android.droiddriver.scroll.Direction.DirectionConverter;
+import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+
+/**
+ * An abstract base class for implementing the <a
+ * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>,
+ * forwarding calls to all methods of {@link ScrollStepStrategy} to delegate.
+ */
+public abstract class ForwardingScrollStepStrategy implements ScrollStepStrategy {
+
+  protected ForwardingScrollStepStrategy() {}
+
+  /**
+   * Returns the backing delegate instance that methods are forwarded to.
+   */
+  protected abstract ScrollStepStrategy delegate();
+
+  public boolean scroll(DroidDriver driver, Finder containerFinder, PhysicalDirection direction) {
+    return delegate().scroll(driver, containerFinder, direction);
+  }
+
+  @Override
+  public final DirectionConverter getDirectionConverter() {
+    return delegate().getDirectionConverter();
+  }
+
+  @Override
+  public void beginScrolling(DroidDriver driver, Finder containerFinder, Finder itemFinder,
+      PhysicalDirection direction) {
+    delegate().beginScrolling(driver, containerFinder, itemFinder, direction);
+  }
+
+  @Override
+  public void endScrolling(DroidDriver driver, Finder containerFinder, Finder itemFinder,
+      PhysicalDirection direction) {
+    delegate().endScrolling(driver, containerFinder, itemFinder, direction);
+  }
+
+  @Override
+  public void doScroll(UiElement container, PhysicalDirection direction) {
+    delegate().doScroll(container, direction);
+  }
+
+  @Override
+  public String toString() {
+    return delegate().toString();
+  }
+
+  /**
+   * Augments the delegate {@link ScrollStepStrategy) - after a successful
+   * scroll, waits until ProgressBar is gone.
+   */
+  public static abstract class ProgressBarScrollStepStrategy extends ForwardingScrollStepStrategy {
+    @Override
+    public boolean scroll(DroidDriver driver, Finder containerFinder, PhysicalDirection direction) {
+      if (super.scroll(driver, containerFinder, direction)) {
+        driver.checkGone(By.className(ProgressBar.class));
+        return true;
+      }
+      return false;
+    }
+
+    /** Convenience method to wrap {@code delegate} with this class */
+    public static ScrollStepStrategy wrap(final ScrollStepStrategy delegate) {
+      return new ProgressBarScrollStepStrategy() {
+        @Override
+        protected ScrollStepStrategy delegate() {
+          return delegate;
+        }
+      };
+    }
+  }
+}