DragListener.java

// Original from Eric Harlow
// http://ericharlow.blogspot.com/2010/10/experience-android-drag-and-drop-list.html
//
// Modifications Copyright 2011 NPR
//
// 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 org.npr.android.widget;

import android.view.View;
import android.widget.ListView;

/**
 * Implement to handle an item being dragged.
 *  
 * @author Eric Harlow
 */
public interface DragListener {
	/**
	 * Called when a drag starts.
   *
	 * @param itemView - the view of the item to be dragged.
	 */
	void onStartDrag(View itemView);
	
	/**
	 * Called when a drag is to be performed.
   *
	 * @param x - horizontal coordinate of MotionEvent.
	 * @param y - vertical coordinate of MotionEvent.
	 * @param listView - the listView that was dragged. This is the actual
   * view item in the list, not the image of the view being dragged.
	 */
	void onDrag(int x, int y, ListView listView);
	
	/**
	 * Called when a drag stops.
   *
	 * Any changes in onStartDrag need to be undone here
	 * so that the view can be used in the list again.
   *
	 * @param itemView - the view of the item that was dragged
	 */
	void onStopDrag(View itemView);
}