1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 package org.chromium.content.browser; 6 7 /** 8 * Used to register listeners that can be notified of changes to the position of a view. 9 */ 10 public interface PositionObserver { 11 public interface Listener { 12 /** 13 * Called during predraw if the position of the underlying view has changed. 14 */ 15 void onPositionChanged(int positionX, int positionY); 16 } 17 18 /** 19 * @return The current x position of the observed view. 20 */ 21 int getPositionX(); 22 23 /** 24 * @return The current y position of the observed view. 25 */ 26 int getPositionY(); 27 28 /** 29 * Register a listener to be called when the position of the underlying view changes. 30 */ 31 void addListener(Listener listener); 32 33 /** 34 * Remove a previously installed listener. 35 */ 36 void removeListener(Listener listener); 37 38 /** 39 * Clears registerned listener(s). 40 */ 41 void clearListener(); 42 } 43
