[SuwLib] Add nested items support

Add nested items support to items framework, which allows ItemGroups
to be placed inside another ItemGroup. Handling of children elements
are at discretion of the parent, but for the case of ItemGroup it
will provide a flattened view of the items.

Change-Id: I17bfd8ee276bf47d388873e68e67324c755425b3

10 files changed, 475 insertions, 39 deletions

diff --git a/library/main/src/com/android/setupwizardlib/SetupWizardItemsLayout.java b/library/main/src/com/android/setupwizardlib/SetupWizardItemsLayout.java
index fbf6618..0a03878 100644
--- a/library/main/src/com/android/setupwizardlib/SetupWizardItemsLayout.java
+++ b/library/main/src/com/android/setupwizardlib/SetupWizardItemsLayout.java
@@ -26,6 +26,8 @@ import com.android.setupwizardlib.items.ItemInflater;
 
 public class SetupWizardItemsLayout extends SetupWizardListLayout {
 
+    private ItemAdapter mAdapter;
+
     public SetupWizardItemsLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
         init(context, attrs, 0);
@@ -42,8 +44,13 @@ public class SetupWizardItemsLayout extends SetupWizardListLayout {
         int xml = a.getResourceId(R.styleable.SuwSetupWizardItemsLayout_android_entries, 0);
         if (xml != 0) {
             ItemGroup inflated = (ItemGroup) new ItemInflater(context).inflate(xml);
-            setAdapter(ItemAdapter.create(inflated));
+            mAdapter = new ItemAdapter(inflated);
+            setAdapter(mAdapter);
         }
         a.recycle();
     }
+
+    public ItemAdapter getAdapter() {
+        return mAdapter;
+    }
 }
diff --git a/library/main/src/com/android/setupwizardlib/items/AbstractItem.java b/library/main/src/com/android/setupwizardlib/items/AbstractItem.java
new file mode 100644
index 0000000..047d18a
--- /dev/null
+++ b/library/main/src/com/android/setupwizardlib/items/AbstractItem.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.setupwizardlib.items;
+
+import android.content.Context;
+import android.util.AttributeSet;
+
+/**
+ * Abstract implementation of an item, which implements {@link IItem} and takes care of implementing
+ * methods for {@link ItemHierarchy} for items representing itself.
+ */
+public abstract class AbstractItem extends AbstractItemHierarchy implements IItem {
+
+    public AbstractItem() {
+        super();
+    }
+
+    public AbstractItem(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public int getCount() {
+        return 1;
+    }
+
+    @Override
+    public IItem getItemAt(int position) {
+        return this;
+    }
+
+    @Override
+    public ItemHierarchy findItemById(int id) {
+        if (id == getId()) {
+            return this;
+        }
+        return null;
+    }
+}
diff --git a/library/main/src/com/android/setupwizardlib/items/AbstractItemHierarchy.java b/library/main/src/com/android/setupwizardlib/items/AbstractItemHierarchy.java
new file mode 100644
index 0000000..c56e3bc
--- /dev/null
+++ b/library/main/src/com/android/setupwizardlib/items/AbstractItemHierarchy.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.setupwizardlib.items;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+
+import com.android.setupwizardlib.R;
+
+import java.util.ArrayList;
+
+/**
+ * An abstract item hierarchy; provides default implementation for ID and observers.
+ */
+public abstract class AbstractItemHierarchy implements ItemHierarchy {
+
+    private ArrayList<Observer> mObservers = new ArrayList<>();
+    private int mId = 0;
+
+    public AbstractItemHierarchy() {
+    }
+
+    public AbstractItemHierarchy(Context context, AttributeSet attrs) {
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SuwAbstractItem);
+        mId = a.getResourceId(R.styleable.SuwAbstractItem_android_id, 0);
+        a.recycle();
+    }
+
+    public void setId(int id) {
+        mId = id;
+    }
+
+    public int getId() {
+        return mId;
+    }
+
+    @Override
+    public void registerObserver(Observer observer) {
+        mObservers.add(observer);
+    }
+
+    @Override
+    public void unregisterObserver(Observer observer) {
+        mObservers.remove(observer);
+    }
+
+    public void notifyChanged() {
+        for (Observer observer : mObservers) {
+            observer.onChanged(this);
+        }
+    }
+}
diff --git a/library/main/src/com/android/setupwizardlib/items/GenericInflater.java b/library/main/src/com/android/setupwizardlib/items/GenericInflater.java
index af4ffcc..f3b6e19 100644
--- a/library/main/src/com/android/setupwizardlib/items/GenericInflater.java
+++ b/library/main/src/com/android/setupwizardlib/items/GenericInflater.java
@@ -39,8 +39,6 @@ import android.view.InflateException;
  * implementing {@link #onAddChildItem(Object, Object)}.
  *
  * @param <T> Type of the items to inflate
- *
- * Modified from android.preference.GenericInflater
  */
 public abstract class GenericInflater<T> {
 
diff --git a/library/main/src/com/android/setupwizardlib/items/IItem.java b/library/main/src/com/android/setupwizardlib/items/IItem.java
new file mode 100644
index 0000000..26391dc
--- /dev/null
+++ b/library/main/src/com/android/setupwizardlib/items/IItem.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.setupwizardlib.items;
+
+import android.view.View;
+
+/**
+ * Representation of an item in an {@link ItemHierarchy}.
+ */
+public interface IItem {
+
+    /**
+     * Get the Android resource ID for locating the layout for this item.
+     *
+     * @return Resource ID for the layout of this item. This layout will be used to inflate the View
+     *         passed to {@link #onBindView(android.view.View)}.
+     */
+    int getLayoutResource();
+
+    /**
+     * Called by items framework to display the data specified by this item. This method should
+     * update {@code view} to reflect its data.
+     *
+     * @param view A view inflated from {@link #getLayoutResource()}, which should be updated to
+     *             display data from this item. This view may be recycled from other items with the
+     *             same layout resource.
+     */
+    void onBindView(View view);
+
+    /**
+     * @return True if this item is enabled.
+     */
+    boolean isEnabled();
+}
diff --git a/library/main/src/com/android/setupwizardlib/items/Item.java b/library/main/src/com/android/setupwizardlib/items/Item.java
index 63baa11..e208848 100644
--- a/library/main/src/com/android/setupwizardlib/items/Item.java
+++ b/library/main/src/com/android/setupwizardlib/items/Item.java
@@ -30,24 +30,24 @@ import com.android.setupwizardlib.R;
  * Definition of an item in SetupWizardItemsLayout. An item is usually defined in XML and inflated
  * using {@link ItemInflater}.
  */
-public class Item {
+public class Item extends AbstractItem {
 
     private boolean mEnabled = true;
     private Drawable mIcon;
-    private int mId = 0;
     private int mLayoutRes;
     private CharSequence mSummary;
     private CharSequence mTitle;
 
     public Item() {
+        super();
         mLayoutRes = getDefaultLayoutResource();
     }
 
     public Item(Context context, AttributeSet attrs) {
+        super(context, attrs);
         TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SuwItem);
         mEnabled = a.getBoolean(R.styleable.SuwItem_android_enabled, true);
         mIcon = a.getDrawable(R.styleable.SuwItem_android_icon);
-        mId = a.getResourceId(R.styleable.SuwItem_android_id, 0);
         mTitle = a.getText(R.styleable.SuwItem_android_title);
         mSummary = a.getText(R.styleable.SuwItem_android_summary);
         mLayoutRes = a.getResourceId(R.styleable.SuwItem_android_layout,
@@ -63,6 +63,7 @@ public class Item {
         mEnabled = enabled;
     }
 
+    @Override
     public boolean isEnabled() {
         return mEnabled;
     }
@@ -75,18 +76,11 @@ public class Item {
         return mIcon;
     }
 
-    public void setId(int id) {
-        mId = id;
-    }
-
-    public int getId() {
-        return mId;
-    }
-
     public void setLayoutResource(int layoutResource) {
         mLayoutRes = layoutResource;
     }
 
+    @Override
     public int getLayoutResource() {
         return mLayoutRes;
     }
@@ -107,6 +101,7 @@ public class Item {
         return mTitle;
     }
 
+    @Override
     public void onBindView(View view) {
         TextView label = (TextView) view.findViewById(R.id.suw_items_title);
         label.setText(getTitle());
@@ -124,6 +119,7 @@ public class Item {
         final Drawable icon = getIcon();
         if (icon != null) {
             final ImageView iconView = (ImageView) view.findViewById(R.id.suw_items_icon);
+            iconView.setImageState(icon.getState(), false /* merge */);
             iconView.setImageLevel(icon.getLevel());
             iconView.setImageDrawable(icon);
             iconContainer.setVisibility(View.VISIBLE);
diff --git a/library/main/src/com/android/setupwizardlib/items/ItemAdapter.java b/library/main/src/com/android/setupwizardlib/items/ItemAdapter.java
index 3fad091..669d104 100644
--- a/library/main/src/com/android/setupwizardlib/items/ItemAdapter.java
+++ b/library/main/src/com/android/setupwizardlib/items/ItemAdapter.java
@@ -23,31 +23,29 @@ import android.view.ViewGroup;
 import android.widget.BaseAdapter;
 
 /**
- * An adapter typically used with ListView to display a list of Items. The list of items used to
- * create this adapter can be inflated by {@link ItemInflater} from XML.
+ * An adapter typically used with ListView to display an
+ * {@link com.android.setupwizardlib.items.ItemHierarchy}. The item hierarchy used to create this
+ * adapter can be inflated by {@link ItemInflater} from XML.
  */
-public class ItemAdapter extends BaseAdapter {
+public class ItemAdapter extends BaseAdapter implements ItemHierarchy.Observer {
 
-    private final Item[] mItems;
+    private final ItemHierarchy mItemHierarchy;
     private ViewTypes mViewTypes = new ViewTypes();
 
-    public static ItemAdapter create(ItemGroup items) {
-        return new ItemAdapter(items.getChildren());
-    }
-
-    public ItemAdapter(Item[] items) {
-        mItems = items;
+    public ItemAdapter(ItemHierarchy hierarchy) {
+        mItemHierarchy = hierarchy;
+        mItemHierarchy.registerObserver(this);
         refreshViewTypes();
     }
 
     @Override
     public int getCount() {
-        return mItems.length;
+        return mItemHierarchy.getCount();
     }
 
     @Override
-    public Item getItem(int position) {
-        return mItems[position];
+    public IItem getItem(int position) {
+        return mItemHierarchy.getItemAt(position);
     }
 
     @Override
@@ -57,7 +55,8 @@ public class ItemAdapter extends BaseAdapter {
 
     @Override
     public int getItemViewType(int position) {
-        int layoutRes = getItem(position).getLayoutResource();
+        IItem item = getItem(position);
+        int layoutRes = item.getLayoutResource();
         return mViewTypes.get(layoutRes);
     }
 
@@ -66,15 +65,16 @@ public class ItemAdapter extends BaseAdapter {
         return mViewTypes.size();
     }
 
-    public void refreshViewTypes() {
-        for (Item item : mItems) {
+    private void refreshViewTypes() {
+        for (int i = 0; i < getCount(); i++) {
+            IItem item = getItem(i);
             mViewTypes.add(item.getLayoutResource());
         }
     }
 
     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
-        Item item = getItem(position);
+        IItem item = getItem(position);
         if (convertView == null) {
             LayoutInflater inflater = LayoutInflater.from(parent.getContext());
             convertView = inflater.inflate(item.getLayoutResource(), parent, false);
@@ -83,6 +83,25 @@ public class ItemAdapter extends BaseAdapter {
         return convertView;
     }
 
+    @Override
+    public void onChanged(ItemHierarchy hierarchy) {
+        refreshViewTypes();
+        notifyDataSetChanged();
+    }
+
+    @Override
+    public boolean isEnabled(int position) {
+        return getItem(position).isEnabled();
+    }
+
+    public ItemHierarchy findItemById(int id) {
+        return mItemHierarchy.findItemById(id);
+    }
+
+    public ItemHierarchy getRootItemHierarchy() {
+        return mItemHierarchy;
+    }
+
     /**
      * A helper class to pack a sparse set of integers (e.g. resource IDs) to a contiguous list of
      * integers (e.g. adapter positions), providing mapping to retrieve the original ID from a given
diff --git a/library/main/src/com/android/setupwizardlib/items/ItemGroup.java b/library/main/src/com/android/setupwizardlib/items/ItemGroup.java
index 3752e68..3e500bb 100644
--- a/library/main/src/com/android/setupwizardlib/items/ItemGroup.java
+++ b/library/main/src/com/android/setupwizardlib/items/ItemGroup.java
@@ -18,23 +18,196 @@ package com.android.setupwizardlib.items;
 
 import android.content.Context;
 import android.util.AttributeSet;
+import android.util.SparseIntArray;
 
 import java.util.ArrayList;
 import java.util.List;
 
-public class ItemGroup extends Item {
+public class ItemGroup extends AbstractItemHierarchy implements ItemHierarchy.Observer {
 
-    private List<Item> mItems = new ArrayList<>();
+    /* static section */
+
+    /**
+     * Binary search for the closest value that's smaller than or equal to {@code value}, and
+     * return the corresponding key.
+     */
+    private static int binarySearch(SparseIntArray array, int value) {
+        final int size = array.size();
+        int lo = 0;
+        int hi = size - 1;
+
+        while (lo <= hi) {
+            final int mid = (lo + hi) >>> 1;
+            final int midVal = array.valueAt(mid);
+
+            if (midVal < value) {
+                lo = mid + 1;
+            } else if (midVal > value) {
+                hi = mid - 1;
+            } else {
+                return array.keyAt(mid);  // value found
+            }
+        }
+        // Value not found. Return the last item before our search range, which is the closest
+        // value smaller than the value we are looking for.
+        return array.keyAt(lo - 1);
+    }
+
+    /* non-static section */
+
+    private List<ItemHierarchy> mChildren = new ArrayList<>();
+
+    /**
+     * A mapping from the index of an item hierarchy in mChildren, to the first position in which
+     * the corresponding child hierarchy represents. For example:
+     *
+     *   ItemHierarchy                 Item               Item Position
+     *       Index
+     * 
+     *         0            [         Wi-Fi AP 1       ]        0
+     *                      |         Wi-Fi AP 2       |        1
+     *                      |         Wi-Fi AP 3       |        2
+     *                      |         Wi-Fi AP 4       |        3
+     *                      [         Wi-Fi AP 5       ]        4
+     * 
+     *         1            [  <Empty Item Hierarchy>  ]
+     * 
+     *         2            [     Use cellular data    ]        5
+     * 
+     *         3            [       Don't connect      ]        6
+     * 
+     * For this example of Wi-Fi screen, the following mapping will be produced:
+     *     [ 0 -> 0 | 2 -> 5 | 3 -> 6 ]
+     * 
+     * Also note how ItemHierarchy index 1 is not present in the map, because it is empty.
+     *
+     * ItemGroup uses this map to look for which ItemHierarchy an item at a given position belongs
+     * to.
+     */
+    private SparseIntArray mHierarchyStart = new SparseIntArray();
+
+    private int mCount = 0;
+    private boolean mDirty = false;
+
+    public ItemGroup() {
+        super();
+    }
 
     public ItemGroup(Context context, AttributeSet attrs) {
+        // Constructor for XML inflation
         super(context, attrs);
     }
 
-    public void addChild(Item child) {
-        mItems.add(child);
+    /**
+     * Add a child hierarchy to this item group.
+     */
+    public void addChild(ItemHierarchy child) {
+        mChildren.add(child);
+        child.registerObserver(this);
+        onHierarchyChanged();
+    }
+
+    /**
+     * Remove a previously added child from this item group.
+     *
+     * @return True if there is a match for the child and it is removed. False if the child could
+     *         not be found in our list of child hierarchies.
+     */
+    public boolean removeChild(ItemHierarchy child) {
+        if (mChildren.remove(child)) {
+            child.unregisterObserver(this);
+            onHierarchyChanged();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Remove all children from this hierarchy.
+     */
+    public void clear() {
+        if (mChildren.size() == 0) {
+            return;
+        }
+
+        for (ItemHierarchy item : mChildren) {
+            item.unregisterObserver(this);
+        }
+        mChildren.clear();
+        onHierarchyChanged();
+    }
+
+    @Override
+    public int getCount() {
+        updateDataIfNeeded();
+        return mCount;
+    }
+
+    @Override
+    public IItem getItemAt(int position) {
+        int itemIndex = getItemIndex(position);
+        ItemHierarchy item = mChildren.get(itemIndex);
+        int subpos = position - mHierarchyStart.get(itemIndex);
+        return item.getItemAt(subpos);
+    }
+
+    @Override
+    public void onChanged(ItemHierarchy hierarchy) {
+        // Need to set dirty, because our children may have gotten more items.
+        mDirty = true;
+        notifyChanged();
+    }
+
+    private void onHierarchyChanged() {
+        onChanged(null);
+    }
+
+    @Override
+    public ItemHierarchy findItemById(int id) {
+        if (id == getId()) {
+            return this;
+        }
+        for (ItemHierarchy child : mChildren) {
+            ItemHierarchy childFindItem = child.findItemById(id);
+            if (childFindItem != null) {
+                return childFindItem;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * If dirty, this method will recalculate the number of items and mHierarchyStart.
+     */
+    private void updateDataIfNeeded() {
+        if (mDirty) {
+            mCount = 0;
+            mHierarchyStart.clear();
+            for (int itemIndex = 0; itemIndex < mChildren.size(); itemIndex++) {
+                ItemHierarchy item = mChildren.get(itemIndex);
+                if (item.getCount() > 0) {
+                    mHierarchyStart.put(itemIndex, mCount);
+                }
+                mCount += item.getCount();
+            }
+            mDirty = false;
+        }
     }
 
-    public Item[] getChildren() {
-        return mItems.toArray(new Item[mItems.size()]);
+    /**
+     * Use binary search to locate the item hierarchy a position is contained in.
+     *
+     * @return Index of the item hierarchy which is responsible for the item at {@code position}.
+     */
+    private int getItemIndex(int position) {
+        updateDataIfNeeded();
+        if (position < 0 || position >= mCount) {
+            throw new IndexOutOfBoundsException("size=" + mCount + "; index=" + position);
+        }
+        int result = binarySearch(mHierarchyStart, position);
+        if (result < 0) {
+            throw new IllegalStateException("Cannot have item start index < 0");
+        }
+        return result;
     }
 }
diff --git a/library/main/src/com/android/setupwizardlib/items/ItemHierarchy.java b/library/main/src/com/android/setupwizardlib/items/ItemHierarchy.java
new file mode 100644
index 0000000..40a56d5
--- /dev/null
+++ b/library/main/src/com/android/setupwizardlib/items/ItemHierarchy.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.setupwizardlib.items;
+
+/**
+ * Representation of zero or more items in a list. Each instance of ItemHierarchy should be capable
+ * of being wrapped in ItemAdapter and be displayed.
+ *
+ * For example, {@link com.android.setupwizardlib.items.Item} is a representation of a single item,
+ * typically with data provided from XML. {@link com.android.setupwizardlib.items.ItemGroup}
+ * represents a list of child item hierarchies it contains, but itself does not do any display.
+ */
+public interface ItemHierarchy {
+
+    /**
+     * Observer for any changes in this hierarchy. If anything updated that causes this hierarchy to
+     * show different content, this observer should be called.
+     */
+    interface Observer {
+        /**
+         * Called when an underlying data update that can cause this hierarchy to show different
+         * content has occurred.
+         */
+        void onChanged(ItemHierarchy itemHierarchy);
+    }
+
+    /**
+     * Register an observer to observe changes for this item hierarchy.
+     */
+    void registerObserver(Observer observer);
+
+    /**
+     * Unregister a previously registered observer.
+     */
+    void unregisterObserver(Observer observer);
+
+    /**
+     * @return the number of items this item hierarchy represent.
+     */
+    int getCount();
+
+    /**
+     * Get the item at position.
+     *
+     * @param position An integer from 0 to {@link #getCount()}}, which indicates the position in
+     *                 this item hierarchy to get the child item.
+     * @return A representation of the item at {@code position}. Must not be {@code null}.
+     */
+    IItem getItemAt(int position);
+
+    /**
+     * Find an item hierarchy within this hierarchy which has the given ID. Or null if no match is
+     * found. This hierarchy will be returned if our ID matches. Same restrictions for Android
+     * resource IDs apply to this ID. In fact, typically this ID is a resource ID generated from
+     * XML.
+     *
+     * @param id An ID to search for in this item hierarchy.
+     * @return An ItemHierarchy which matches the given ID.
+     */
+    ItemHierarchy findItemById(int id);
+}
diff --git a/library/main/src/com/android/setupwizardlib/items/ItemInflater.java b/library/main/src/com/android/setupwizardlib/items/ItemInflater.java
index e25e2ad..6bd77ac 100644
--- a/library/main/src/com/android/setupwizardlib/items/ItemInflater.java
+++ b/library/main/src/com/android/setupwizardlib/items/ItemInflater.java
@@ -23,7 +23,7 @@ import android.content.Context;
  *
  * Modified from android.support.v7.preference.PreferenceInflater
  */
-public class ItemInflater extends GenericInflater<Item> {
+public class ItemInflater extends GenericInflater<ItemHierarchy> {
 
     private static final String TAG = "ItemInflater";
 
@@ -49,7 +49,7 @@ public class ItemInflater extends GenericInflater<Item> {
     }
 
     @Override
-    protected void onAddChildItem(Item parent, Item child) {
+    protected void onAddChildItem(ItemHierarchy parent, ItemHierarchy child) {
         if (parent instanceof ItemGroup) {
             ((ItemGroup) parent).addChild(child);
         } else {