Android GestureDetector手势识别类

为了加强鼠标响应事件，Android提供了GestureDetector手势识别类。通过GestureDetector.OnGestureListener来获取当前被触发的操作手势（Single Tap Up、Show Press、Long Press、Scroll、Down、Fling），具体包括以下几种：

boolean onDoubleTap(MotionEvent e)
解释：双击的第二下Touch down时触发
boolean onDoubleTapEvent(MotionEvent e)
解释：双击的第二下Touch down和up都会触发，可用e.getAction()区分。
boolean onDown(MotionEvent e)
解释：Touch down时触发
boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
解释：Touch了滑动一点距离后，up时触发。
void onLongPress(MotionEvent e)
解释：Touch了不移动一直Touch down时触发
boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
解释：Touch了滑动时触发。
void onShowPress(MotionEvent e)
解释：Touch了还没有滑动时触发
（与onDown，onLongPress比较
onDown只要Touch down一定立刻触发。
而Touchdown后过一会没有滑动先触发onShowPress再是onLongPress。
所以Touchdown后一直不滑动，onDown->onShowPress->onLongPress这个顺序触发。

boolean onSingleTapConfirmed(MotionEvent e)
boolean onSingleTapUp(MotionEvent e)
解释：上面这两个函数都是在touch down后又没有滑动（onScroll），又没有长按（onLongPress），然后Touchup时触发。

点击一下非常快的（不滑动）Touchup：
onDown->onSingleTapUp->onSingleTapConfirmed
点击一下稍微慢点的（不滑动）Touchup：
onDown->onShowPress->onSingleTapUp->onSingleTapConfirmed

使用GestureDetector需要在View中重写onTouchEvent事件，例如：

[java] view plain copy print ?

1. GestureDetector mGesture = null;
2. @Override
3. public boolean onTouch(View v, MotionEvent event)
4. {
5. // TODO Auto-generated method stub
6. return mGesture.onTouchEvent(event);
7. }

GestureDetector mGesture = null; @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub return mGesture.onTouchEvent(event); }

详细的测试例子如下：

[cpp] view plain copy print ?

1. package com.jiubang.android.gesturetest;
3. import android.app.Activity;
4. import android.os.Bundle;
5. import android.util.Log;
6. import android.view.GestureDetector;
7. import android.view.MotionEvent;
8. import android.view.View;
9. import android.view.GestureDetector.SimpleOnGestureListener;
10. import android.view.View.OnTouchListener;
11. import android.widget.Button;
13. public class GestureActivity extends Activity
14. implements OnTouchListener
15. {
16. private Button mButton = null;
17. GestureDetector mGesture = null;
19. /** Called when the activity is first created. */
20. @Override
21. public void onCreate(Bundle savedInstanceState) {
22. super.onCreate(savedInstanceState);
23. setContentView(R.layout.main);
25. Log.i("TEST", "onCreate");
26. mButton = (Button)findViewById(R.id.button1);
27. mButton.setOnTouchListener(this);
28. mGesture = new GestureDetector(this, new GestureListener());
29. }
31. @Override
32. public boolean onTouch(View v, MotionEvent event)
33. {
34. // TODO Auto-generated method stub
35. return mGesture.onTouchEvent(event);
36. }
38. class GestureListener extends SimpleOnGestureListener
39. {
41. @Override
42. public boolean onDoubleTap(MotionEvent e)
43. {
44. // TODO Auto-generated method stub
45. Log.i("TEST", "onDoubleTap");
46. return super.onDoubleTap(e);
47. }
49. @Override
50. public boolean onDown(MotionEvent e)
51. {
52. // TODO Auto-generated method stub
53. Log.i("TEST", "onDown");
54. return super.onDown(e);
55. }
57. @Override
58. public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
59. float velocityY)
60. {
61. // TODO Auto-generated method stub
62. Log.i("TEST", "onFling:velocityX = " + velocityX + " velocityY" + velocityY);
63. return super.onFling(e1, e2, velocityX, velocityY);
64. }
66. @Override
67. public void onLongPress(MotionEvent e)
68. {
69. // TODO Auto-generated method stub
70. Log.i("TEST", "onLongPress");
71. super.onLongPress(e);
72. }
74. @Override
75. public boolean onScroll(MotionEvent e1, MotionEvent e2,
76. float distanceX, float distanceY)
77. {
78. // TODO Auto-generated method stub
79. Log.i("TEST", "onScroll:distanceX = " + distanceX + " distanceY = " + distanceY);
80. return super.onScroll(e1, e2, distanceX, distanceY);
81. }
83. @Override
84. public boolean onSingleTapUp(MotionEvent e)
85. {
86. // TODO Auto-generated method stub
87. Log.i("TEST", "onSingleTapUp");
88. return super.onSingleTapUp(e);
89. }
91. }
92. }