ListView: implement header and footer Views

Underlying HeaderViewListAdapter class is copied from AOSP

src/api-impl/android/widget/AbsListView.java

@@ -8,7 +8,7 @@ import android.view.ViewGroup;
 public abstract class AbsListView extends AdapterView {
 
 	public boolean mIsChildViewEnabled = false;  // this field gets directly accessed by androidx DropDownListView
-	private Observer observer = new Observer();
+	protected Observer observer = new Observer();
 
 	public AbsListView(Context context) {
 		super(context);
@@ -79,7 +79,7 @@ public abstract class AbsListView extends AdapterView {
 
 	public interface SelectionBoundsAdjuster {}
 
-	private class Observer extends DataSetObserver {
+	class Observer extends DataSetObserver {
 
 		@Override
 		public void onChanged() {

src/api-impl/android/widget/HeaderViewListAdapter.java

@@ -1,5 +1,231 @@
+/*
+ * Copyright (C) 2006 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 android.widget;
 
-public class HeaderViewListAdapter {
+import java.util.ArrayList;
+
+import android.database.DataSetObserver;
+import android.view.View;
+import android.view.ViewGroup;
+
+/**
+ * ListAdapter used when a ListView has header views. This ListAdapter
+ * wraps another one and also keeps track of the header views and their
+ * associated data objects.
+ *<p>This is intended as a base class; you will probably not need to
+ * use this class directly in your own code.
+ */
+public class HeaderViewListAdapter implements ListAdapter, Filterable {
+
+	private final ListAdapter mAdapter;
+
+	// These two ArrayList are assumed to NOT be null.
+	// They are indeed created when declared in ListView and then shared.
+	ArrayList<ListView.FixedViewInfo> mHeaderViewInfos;
+	ArrayList<ListView.FixedViewInfo> mFooterViewInfos;
+
+	// Used as a placeholder in case the provided info views are indeed null.
+	// Currently only used by some CTS tests, which may be removed.
+	static final ArrayList<ListView.FixedViewInfo> EMPTY_INFO_LIST =
+		new ArrayList<ListView.FixedViewInfo>();
+
+	boolean mAreAllFixedViewsSelectable;
+
+	public HeaderViewListAdapter(ArrayList<ListView.FixedViewInfo> headerViewInfos,
+								 ArrayList<ListView.FixedViewInfo> footerViewInfos,
+								 ListAdapter adapter) {
+		mAdapter = adapter;
+
+		if (headerViewInfos == null) {
+			mHeaderViewInfos = EMPTY_INFO_LIST;
+		} else {
+			mHeaderViewInfos = headerViewInfos;
+		}
+
+		if (footerViewInfos == null) {
+			mFooterViewInfos = EMPTY_INFO_LIST;
+		} else {
+			mFooterViewInfos = footerViewInfos;
+		}
+
+		mAreAllFixedViewsSelectable =
+				areAllListInfosSelectable(mHeaderViewInfos)
+				&& areAllListInfosSelectable(mFooterViewInfos);
+	}
+
+	public int getHeadersCount() {
+		return mHeaderViewInfos.size();
+	}
+
+	public int getFootersCount() {
+		return mFooterViewInfos.size();
+	}
+
+	public boolean isEmpty() {
+		return mAdapter == null || mAdapter.isEmpty();
+	}
+
+	private boolean areAllListInfosSelectable(ArrayList<ListView.FixedViewInfo> infos) {
+		if (infos != null) {
+			for (ListView.FixedViewInfo info : infos) {
+				if (!info.isSelectable) {
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+
+	public boolean removeHeader(View v) {
+		for (int i = 0; i < mHeaderViewInfos.size(); i++) {
+			ListView.FixedViewInfo info = mHeaderViewInfos.get(i);
+			if (info.view == v) {
+				mHeaderViewInfos.remove(i);
+
+				mAreAllFixedViewsSelectable =
+						areAllListInfosSelectable(mHeaderViewInfos)
+						&& areAllListInfosSelectable(mFooterViewInfos);
+
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	public boolean removeFooter(View v) {
+		for (int i = 0; i < mFooterViewInfos.size(); i++) {
+			ListView.FixedViewInfo info = mFooterViewInfos.get(i);
+			if (info.view == v) {
+				mFooterViewInfos.remove(i);
+
+				mAreAllFixedViewsSelectable =
+						areAllListInfosSelectable(mHeaderViewInfos)
+						&& areAllListInfosSelectable(mFooterViewInfos);
+
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	public int getCount() {
+		if (mAdapter != null) {
+			return getFootersCount() + getHeadersCount() + mAdapter.getCount();
+		} else {
+			return getFootersCount() + getHeadersCount();
+		}
+	}
+
+	public Object getItem(int position) {
+		// Header (negative positions will throw an IndexOutOfBoundsException)
+		int numHeaders = getHeadersCount();
+		if (position < numHeaders) {
+			return mHeaderViewInfos.get(position).data;
+		}
+
+		// Adapter
+		final int adjPosition = position - numHeaders;
+		int adapterCount = 0;
+		if (mAdapter != null) {
+			adapterCount = mAdapter.getCount();
+			if (adjPosition < adapterCount) {
+				return mAdapter.getItem(adjPosition);
+			}
+		}
+
+		// Footer (off-limits positions will throw an IndexOutOfBoundsException)
+		return mFooterViewInfos.get(adjPosition - adapterCount).data;
+	}
+
+	public long getItemId(int position) {
+		int numHeaders = getHeadersCount();
+		if (mAdapter != null && position >= numHeaders) {
+			int adjPosition = position - numHeaders;
+			int adapterCount = mAdapter.getCount();
+			if (adjPosition < adapterCount) {
+				return mAdapter.getItemId(adjPosition);
+			}
+		}
+		return -1;
+	}
+
+	public boolean hasStableIds() {
+		if (mAdapter != null) {
+			return mAdapter.hasStableIds();
+		}
+		return false;
+	}
+
+	public View getView(int position, View convertView, ViewGroup parent) {
+		// Header (negative positions will throw an IndexOutOfBoundsException)
+		int numHeaders = getHeadersCount();
+		if (position < numHeaders) {
+			return mHeaderViewInfos.get(position).view;
+		}
+
+		// Adapter
+		final int adjPosition = position - numHeaders;
+		int adapterCount = 0;
+		if (mAdapter != null) {
+			adapterCount = mAdapter.getCount();
+			if (adjPosition < adapterCount) {
+				return mAdapter.getView(adjPosition, convertView, parent);
+			}
+		}
+
+		// Footer (off-limits positions will throw an IndexOutOfBoundsException)
+		return mFooterViewInfos.get(adjPosition - adapterCount).view;
+	}
+
+	public int getItemViewType(int position) {
+		int numHeaders = getHeadersCount();
+		if (mAdapter != null && position >= numHeaders) {
+			int adjPosition = position - numHeaders;
+			int adapterCount = mAdapter.getCount();
+			if (adjPosition < adapterCount) {
+				return mAdapter.getItemViewType(adjPosition);
+			}
+		}
+
+		return /*ITEM_VIEW_TYPE_HEADER_OR_FOOTER*/ -2;
+	}
+
+	public int getViewTypeCount() {
+		if (mAdapter != null) {
+			return mAdapter.getViewTypeCount();
+		}
+		return 1;
+	}
+
+	public void registerDataSetObserver(DataSetObserver observer) {
+		if (mAdapter != null) {
+			mAdapter.registerDataSetObserver(observer);
+		}
+	}
+
+	public void unregisterDataSetObserver(DataSetObserver observer) {
+		if (mAdapter != null) {
+			mAdapter.unregisterDataSetObserver(observer);
+		}
+	}
 	
+	public ListAdapter getWrappedAdapter() {
+		return mAdapter;
+	}
 }

src/api-impl/android/widget/ListView.java

@@ -1,5 +1,6 @@
 package android.widget;
 
+import java.util.ArrayList;
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
@@ -7,6 +8,21 @@ import android.view.View;
 
 public class ListView extends AbsListView {
 
+	static class FixedViewInfo {
+		public View view;
+		public Object data;
+		public boolean isSelectable;
+
+		public FixedViewInfo(View view, Object data, boolean isSelectable) {
+			this.view = view;
+			this.data = data;
+			this.isSelectable = isSelectable;
+		}
+	}
+
+	private ArrayList<FixedViewInfo> headerViews = new ArrayList<FixedViewInfo>();
+	private ArrayList<FixedViewInfo> footerViews = new ArrayList<FixedViewInfo>();
+
 	public ListView(Context context) {
 		super(context);
 	}
@@ -15,35 +31,72 @@ public class ListView extends AbsListView {
 		super(context, attributeSet);
 	}
 
+	public ListView(Context context, AttributeSet attributeSet, int defStyleAttr) {
+		super(context, attributeSet, defStyleAttr);
+	}
+
+	@Override
+	public void setAdapter(ListAdapter adapter) {
+		if (getHeaderViewsCount() > 0 || getFooterViewsCount() > 0) {
+			adapter = new HeaderViewListAdapter(headerViews, footerViews, adapter);
+		}
+		super.setAdapter(adapter);
+	}
+
 	public int getDividerHeight() {return 0;}
 
 	public Drawable getDivider() {return null;}
 
 	public void setTextFilterEnabled(boolean enabled) {}
 
-	public void addHeaderView(View v, Object data, boolean isSelectable) {}
+	public void addHeaderView(View v, Object data, boolean isSelectable) {
+		headerViews.add(new FixedViewInfo(v, data, isSelectable));
+		if (getAdapter() instanceof HeaderViewListAdapter) {
+			observer.onChanged();
+		} else if (getAdapter() != null) {
+			setAdapter(getAdapter());
+		}
+	}
 
 	public void setDrawSelectorOnTop(boolean dummy) {}
 
-	public void addHeaderView(View view) {}
+	public void addHeaderView(View view) {
+		addHeaderView(view, null, true);
+	}
 
-	public boolean removeHeaderView(View view) { return true; }
+	public boolean removeHeaderView(View view) {
+		boolean result = false;
+		if (getAdapter() instanceof HeaderViewListAdapter)
+			result = ((HeaderViewListAdapter)getAdapter()).removeHeader(view);
+		if (result)
+			observer.onChanged();
+		return result;
+	}
 
 	public int getHeaderViewsCount() {
-		return 0;
+		return headerViews.size();
 	}
 
 	public int getFooterViewsCount() {
-		return 0;
+		return footerViews.size();
 	}
 
 	public void setDivider(Drawable drawable) {}
 
 	public void setSelectionFromTop(int position, int y) {}
 
-	public void addFooterView(View v, Object data, boolean isSelectable) {}
+	public void addFooterView(View v, Object data, boolean isSelectable) {
+		footerViews.add(new FixedViewInfo(v, data, isSelectable));
+		if (getAdapter() instanceof HeaderViewListAdapter) {
+			observer.onChanged();
+		} else if (getAdapter() != null) {
+			setAdapter(getAdapter());
+		}
+	}
 
-	public void addFooterView(View v) {}
+	public void addFooterView(View v) {
+		addFooterView(v, null, true);
+	}
 
 	public void setDividerHeight(int height) {}
 }