/* * Copyright (C) 2013 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.support.v4.widget; import android.view.View.OnTouchListener; /** * Helper for accessing features in PopupMenu introduced after API level 4 in a * backwards compatible fashion. */ public class PopupMenuCompat { /** * Interface for the full API. */ interface PopupMenuImpl { public OnTouchListener getDragToOpenListener(Object popupMenu); } /** * Interface implementation that doesn't use anything above v4 APIs. */ static class BasePopupMenuImpl implements PopupMenuImpl { @Override public OnTouchListener getDragToOpenListener(Object popupMenu) { return null; } } /** * Interface implementation for devices with at least KitKat APIs. */ static class KitKatPopupMenuImpl extends BasePopupMenuImpl { @Override public OnTouchListener getDragToOpenListener(Object popupMenu) { return PopupMenuCompatKitKat.getDragToOpenListener(popupMenu); } } /** * Select the correct implementation to use for the current platform. */ static final PopupMenuImpl IMPL; static { final int version = android.os.Build.VERSION.SDK_INT; if (version >= 19) { IMPL = new KitKatPopupMenuImpl(); } else { IMPL = new BasePopupMenuImpl(); } } private PopupMenuCompat() { // This class is not publicly instantiable. } /** * On API {@link android.os.Build.VERSION_CODES#KITKAT} and higher, returns * an {@link OnTouchListener} that can be added to the anchor view to * implement drag-to-open behavior. *

* When the listener is set on a view, touching that view and dragging * outside of its bounds will open the popup window. Lifting will select the * currently touched list item. *

* Example usage: *

     * PopupMenu myPopup = new PopupMenu(context, myAnchor);
     * myAnchor.setOnTouchListener(myPopup.getDragToOpenListener());
     * 
* * @param popupMenu the PopupMenu against which to invoke the method * @return a touch listener that controls drag-to-open behavior, or null on * unsupported APIs */ public static OnTouchListener getDragToOpenListener(Object popupMenu) { return IMPL.getDragToOpenListener(popupMenu); } }