双指拖动缩放图片

iv = (ImageView) findViewById(R.id.iv); 
iv.setOnTouchListener(new MulitPointTouchListener(iv)); 
iv.setScaleType(ScaleType.CENTER_INSIDE); 

Java代码  10f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; } break; case MotionEvent.ACTION_UP: Log.w("FLAG", "ACTION_UP"); case MotionEvent.ACTION_POINTER_UP: Log.w("FLAG", "ACTION_POINTER_UP"); mode = NONE; break; case MotionEvent.ACTION_MOVE: Log.w("FLAG", "ACTION_MOVE"); if (mode == DRAG) { matrix.set(savedMatrix); matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); } else if (mode == ZOOM) { float newDist = spacing(event); if (newDist > 10f) { matrix.set(savedMatrix); float scale = newDist / oldDist; matrix.postScale(scale, scale, mid.x, mid.y); } } break; } view.setImageMatrix(matrix); return true; } private float spacing(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } private void midPoint(PointF point, MotionEvent event) { float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); } } " quality="high" allowscriptaccess="always" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"> 

1. public class MulitPointTouchListener implements OnTouchListener {  
2.   
3.         Matrix matrix = new Matrix();  
4.         Matrix savedMatrix = new Matrix();  
5.   
6.         public ImageView image;  
7.         static final int NONE = 0;  
8.         static final int DRAG = 1;  
9.         static final int ZOOM = 2;  
10.         int mode = NONE;  
11.   
12.         PointF start = new PointF();  
13.         PointF mid = new PointF();  
14.         float oldDist = 1f;  
15.   
16.         public MulitPointTouchListener(ImageView image) {  
17.             super();  
18.             this.image = image;  
19.         }  
20.   
21.         @Override  
22.         public boolean onTouch(View v, MotionEvent event) {  
23.             this.image.setScaleType(ScaleType.MATRIX);  
24.   
25.             ImageView view = (ImageView) v;  
26.             // dumpEvent(event);  
27.   
28.             switch (event.getAction() & MotionEvent.ACTION_MASK) {  
29.   
30.             case MotionEvent.ACTION_DOWN:  
31.   
32.                 Log.w("FLAG", "ACTION_DOWN");  
33.                 matrix.set(view.getImageMatrix());  
34.                 savedMatrix.set(matrix);  
35.                 start.set(event.getX(), event.getY());  
36.                 mode = DRAG;  
37.                 break;  
38.             case MotionEvent.ACTION_POINTER_DOWN:  
39.                 Log.w("FLAG", "ACTION_POINTER_DOWN");  
40.                 oldDist = spacing(event);  
41.                 if (oldDist > 10f) {  
42.                     savedMatrix.set(matrix);  
43.                     midPoint(mid, event);  
44.                     mode = ZOOM;  
45.                 }  
46.                 break;  
47.             case MotionEvent.ACTION_UP:  
48.                 Log.w("FLAG", "ACTION_UP");  
49.             case MotionEvent.ACTION_POINTER_UP:  
50.                 Log.w("FLAG", "ACTION_POINTER_UP");  
51.                 mode = NONE;  
52.                 break;  
53.             case MotionEvent.ACTION_MOVE:  
54.                 Log.w("FLAG", "ACTION_MOVE");  
55.                 if (mode == DRAG) {  
56.                     matrix.set(savedMatrix);  
57.                     matrix.postTranslate(event.getX() - start.x, event.getY()  
58.                             - start.y);  
59.                 } else if (mode == ZOOM) {  
60.                     float newDist = spacing(event);  
61.                     if (newDist > 10f) {  
62.                         matrix.set(savedMatrix);  
63.                         float scale = newDist / oldDist;  
64.                         matrix.postScale(scale, scale, mid.x, mid.y);  
65.                     }  
66.                 }  
67.                 break;  
68.             }  
69.   
70.             view.setImageMatrix(matrix);  
71.             return true;  
72.         }  
73.   
74.         private float spacing(MotionEvent event) {  
75.             float x = event.getX(0) - event.getX(1);  
76.             float y = event.getY(0) - event.getY(1);  
77.             return FloatMath.sqrt(x * x + y * y);  
78.         }  
79.   
80.         private void midPoint(PointF point, MotionEvent event) {  
81.             float x = event.getX(0) + event.getX(1);  
82.             float y = event.getY(0) + event.getY(1);  
83.             point.set(x / 2, y / 2);  
84.         }  
85.     }