Android通过手势（多点）缩放和拖拽图片

在MotionEvent中有两个事件值得注意一下，分别是ACTION_DOWN和ACTION_POINTER_DOWN。
ACTION_DOWN：这个很好理解，当屏幕检测到有手指按下之后就触发到这个事件。
ACTION_POINTER_DOWN：这个是实现多点的关键，当屏幕检测到有多个手指同时按下之后，就触发了这个事件。
通过getAction()可以获得当前屏幕的事件类型：ACTION_DOWN, ACTION_MOVE, ACTION_UP, or ACTION_CANCEL。但是如果像获得如上的ACTION_POINTER_DOWN，则得和ACTION_MASK相与才能得到ACTION_POINTER_DOWN事件。
所以我们运用一个switch-case结构就可以实现对图片进行拖拽或缩放，而缩放的只要思想是在移动的过程中计算两个点之间的距离，然后再进行缩放。
多点触摸是可以的，还是用OnTouchListener。
单点触摸取得坐标的时候一般都用event.getX()和event.getY()。
其实还有一组方法，
event.getX(int pointerIndex)和event.getY(int pointerIndex)，
看参数就知道怎么用了吧。
在onTouch(View v, MotionEvent event)的里面，
switch (event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN:
//单点模式
case MotionEvent.ACTION_POINTER_DOWN:
//计算当前点和前一个DOWN点之间的距离，超过一定范围可以认为是多点模式
case MotionEvent.ACTION_MOVE:
//多点模式时，计算两点距离，通过与第一次的计算值的比例，得到缩放比例
//单点模式时，计算移动距离，设置LayoutParams
case MotionEvent.ACTION_POINTER_UP:
//重置掉多点模式和记录的距离等等
case MotionEvent.ACTION_UP:
//处理单点模式，计算移动距离，设置LayoutParams
}

<wbr><wbr><wbr><wbr>上代码：</wbr></wbr></wbr></wbr>

1. <wbr><wbr><wbr><wbr>@Override<br></wbr></wbr></wbr></wbr>
2. <wbr><wbr><wbr><wbr><wbr><wbr>public boolean onTouch(View v, MotionEvent event) {<br></wbr></wbr></wbr></wbr></wbr></wbr>
3. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>ImageView view = (ImageView) v;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
4. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>dumpEvent(event);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
5. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>// Handle touch events here...<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
6. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>switch (event.getAction() &amp; MotionEvent.ACTION_MASK) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
7. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>case MotionEvent.ACTION_DOWN:<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
8. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>matrix.set(view.getImageMatrix());<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
9. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>savedMatrix.set(matrix);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
10. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>start.set(event.getX(), event.getY());<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
11. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, "mode=DRAG");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
12. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>mode = DRAG;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
13. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, "mode=NONE");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
14. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>break;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
15. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>case MotionEvent.ACTION_POINTER_DOWN:<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
16. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>oldDist = spacing(event);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
17. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, "oldDist=" + oldDist);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
18. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if (oldDist &gt; 10f) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
19. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>savedMatrix.set(matrix);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
20. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>midPoint(mid, event);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
21. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>mode = ZOOM;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
22. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, "mode=ZOOM");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
23. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}// ACTION_DOWN, ACTION_MOVE, ACTION_UP, or ACTION_CANCEL.<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
24. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>break;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
25. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>case MotionEvent.ACTION_UP:<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
26. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>case MotionEvent.ACTION_POINTER_UP:<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
27. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>mode = NONE;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
28. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>break;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
29. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>case MotionEvent.ACTION_MOVE:<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
30. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if (mode == DRAG) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
31. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>// ...<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
32. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>matrix.set(savedMatrix);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
33. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>matrix.postTranslate(event.getX() - start.x, event.getY()<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
34. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>- start.y);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
35. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>} else if (mode == ZOOM) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
36. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float newDist = spacing(event);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
37. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, "newDist=" + newDist);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
38. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if (newDist &gt; 10f) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
39. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>matrix.set(savedMatrix);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
40. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float scale = newDist / oldDist;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
41. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>matrix.postScale(scale, scale, mid.x, mid.y);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
42. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
43. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
44. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>break;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
45. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
46. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>view.setImageMatrix(matrix);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
47. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>return true; // indicate event was handled<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
48. <wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr>
49. <wbr><wbr><wbr><wbr><wbr><wbr>private void dumpEvent(MotionEvent event) {<br></wbr></wbr></wbr></wbr></wbr></wbr>
50. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
51. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
52. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>StringBuilder sb = new StringBuilder();<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
53. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>int action = event.getAction();<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
54. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>int actionCode = action &amp; MotionEvent.ACTION_MASK;<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
55. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("event ACTION_").append(names[actionCode]);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
56. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if (actionCode == MotionEvent.ACTION_POINTER_DOWN<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
57. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>|| actionCode == MotionEvent.ACTION_POINTER_UP) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
58. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("(pid ").append(<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
59. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>action &gt;&gt; MotionEvent.ACTION_POINTER_ID_SHIFT);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
60. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append(")");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
61. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
62. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("[");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
63. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>for (int i = 0; i &lt; event.getPointerCount(); i++) {<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
64. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("#").append(i);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
65. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("(pid ").append(event.getPointerId(i));<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
66. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append(")=").append((int) event.getX(i));<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
67. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append(",").append((int) event.getY(i));<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
68. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if (i + 1 &lt; event.getPointerCount())<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
69. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append(";");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
70. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
71. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>sb.append("]");<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
72. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>//Log.d(TAG, sb.toString());<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
73. <wbr><wbr><wbr><wbr><wbr><wbr>} </wbr></wbr></wbr></wbr></wbr></wbr>

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求两点间距离：

1. private float spacing(MotionEvent event) {
2. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float x = event.getX(0) - event.getX(1);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
3. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float y = event.getY(0) - event.getY(1);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
4. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>return FloatMath.sqrt(x * x + y * y);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
5. <wbr><wbr><wbr><wbr><wbr><wbr>} </wbr></wbr></wbr></wbr></wbr></wbr>

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求两点间中点：

1. <wbr><wbr><wbr><wbr><wbr><wbr>private void midPoint(PointF point, MotionEvent event) {<br></wbr></wbr></wbr></wbr></wbr></wbr>
2. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float x = event.getX(0) + event.getX(1);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
3. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>float y = event.getY(0) + event.getY(1);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
4. <wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>point.set(x/2, y/2);<br></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>
5. <wbr><wbr><wbr><wbr><wbr><wbr>} </wbr></wbr></wbr></wbr></wbr></wbr>

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还有一点要主要的是：ImageView在main.xml 设置为：<wbr><wbr>android:scaleType="matrix"</wbr></wbr>