Fixed group and child view caching in SimpleExpandableListAdapter.

Now the adapter reports the correct type count and type for group and child
views by overriding the respective methods from the base class. Each group
view has two types, one for expanded views, one for collapsed views. Each
child view has two types, one for the last view within a group, one for the
other views within a group.

Change-Id: I117b2c0f7e98fb7fe2fdd35c15f7d1f9dc06674f
Signed-off-by: Georg Hofmann <georg.hofmann@gmail.com>

Author: hofmann

core/java/android/widget/SimpleExpandableListAdapter.java

@@ -38,6 +38,8 @@
  */
 public class SimpleExpandableListAdapter extends BaseExpandableListAdapter {
     private List<? extends Map<String, ?>> mGroupData;
+    // Keeps track of if a group is currently expanded or not
+    private boolean[] mIsGroupExpanded;
     private int mExpandedGroupLayout;
     private int mCollapsedGroupLayout;
     private String[] mGroupFrom;
@@ -196,6 +198,8 @@ public SimpleExpandableListAdapter(Context context,
             int childLayout, int lastChildLayout, String[] childFrom,
             int[] childTo) {
         mGroupData = groupData;
+        // Initially all groups are not expanded
+        mIsGroupExpanded = new boolean[groupData.size()];
         mExpandedGroupLayout = expandedGroupLayout;
         mCollapsedGroupLayout = collapsedGroupLayout;
         mGroupFrom = groupFrom;
@@ -298,4 +302,52 @@ public boolean hasStableIds() {
         return true;
     }
 
+    /**
+     * {@inheritDoc}
+     * @return 1 for the last child in a group, 0 for the other children.
+     */
+    @Override
+    public int getChildType(int groupPosition, int childPosition) {
+        final int childrenInGroup = getChildrenCount(groupPosition);
+        return childPosition == childrenInGroup - 1 ? 1 : 0;
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return 2, one type for the last child in a group, one for the other children.
+     */
+    @Override
+    public int getChildTypeCount() {
+        return 2;
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return 1 for an expanded group view, 0 for a collapsed one.
+     */
+    @Override
+    public int getGroupType(int groupPosition) {
+        return mIsGroupExpanded[groupPosition] ? 1 : 0;
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return 2, one for a collapsed group view, one for an expanded one.
+     */
+    @Override
+    public int getGroupTypeCount() {
+        return 2;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void onGroupCollapsed(int groupPosition) {
+        mIsGroupExpanded[groupPosition] = false;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void onGroupExpanded(int groupPosition) {
+        mIsGroupExpanded[groupPosition] = true;
+    }
 }