记录一个用于多点触控，移动放大缩小的TouchListener
1 import android.graphics.Matrix; 2 import android.graphics.PointF; 3 import android.util.FloatMath; 4 import android.view.MotionEvent; 5 import android.view.View; 6 import android.view.View.OnTouchListener; 7 import android.widget.ImageView; 8 9 public class MulitPointTouchListener implements OnTouchListener { 10 11 private static final String TAG = "Touch"; 12 // These matrices will be used to move and zoom image 13 Matrix matrix = new Matrix(); 14 Matrix savedMatrix = new Matrix(); 15 16 // We can be in one of these 3 states 17 static final int NONE = 0; 18 static final int DRAG = 1; 19 static final int ZOOM = 2; 20 int mode = NONE; 21 22 // Remember some things for zooming 23 PointF start = new PointF(); 24 PointF mid = new PointF(); 25 float oldDist = 1f; 26 27 @Override 28 public boolean onTouch(View v, MotionEvent event) { 29 30 ImageView view = (ImageView) v; 31 // Log.e("view_width", 32 // view.getImageMatrix()..toString()+"*"+v.getWidth()); 33 // Dump touch event to log 34 dumpEvent(event); 35 36 // Handle touch events here... 37 switch (event.getAction() & MotionEvent.ACTION_MASK) { 38 case MotionEvent.ACTION_DOWN: 39 40 matrix.set(view.getImageMatrix()); 41 savedMatrix.set(matrix); 42 start.set(event.getX(), event.getY()); 43 //Log.d(TAG, "mode=DRAG"); 44 mode = DRAG; 45 46 47 //Log.d(TAG, "mode=NONE"); 48 break; 49 case MotionEvent.ACTION_POINTER_DOWN: 50 oldDist = spacing(event); 51 //Log.d(TAG, "oldDist=" + oldDist); 52 if (oldDist > 10f) { 53 savedMatrix.set(matrix); 54 midPoint(mid, event); 55 mode = ZOOM; 56 //Log.d(TAG, "mode=ZOOM"); 57 } 58 break; 59 case MotionEvent.ACTION_UP: 60 case MotionEvent.ACTION_POINTER_UP: 61 mode = NONE; 62 //Log.e("view.getWidth", view.getWidth() + ""); 63 //Log.e("view.getHeight", view.getHeight() + ""); 64 65 break; 66 case MotionEvent.ACTION_MOVE: 67 if (mode == DRAG) { 68 // ... 69 matrix.set(savedMatrix); 70 matrix.postTranslate(event.getX() - start.x, event.getY() 71 - start.y); 72 } else if (mode == ZOOM) { 73 float newDist = spacing(event); 74 //Log.d(TAG, "newDist=" + newDist); 75 if (newDist > 10f) { 76 matrix.set(savedMatrix); 77 float scale = newDist / oldDist; 78 matrix.postScale(scale, scale, mid.x, mid.y); 79 } 80 } 81 break; 82 } 83 84 view.setImageMatrix(matrix); 85 return true; // indicate event was handled 86 } 87 88 private void dumpEvent(MotionEvent event) { 89 String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE", 90 "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" }; 91 StringBuilder sb = new StringBuilder(); 92 int action = event.getAction(); 93 int actionCode = action & MotionEvent.ACTION_MASK; 94 sb.append("event ACTION_").append(names[actionCode]); 95 if (actionCode == MotionEvent.ACTION_POINTER_DOWN 96 || actionCode == MotionEvent.ACTION_POINTER_UP) { 97 sb.append("(pid ").append( 98 action >> MotionEvent.ACTION_POINTER_ID_SHIFT); 99 sb.append(")"); 100 } 101 sb.append("["); 102 for (int i = 0; i < event.getPointerCount(); i++) { 103 sb.append("#").append(i); 104 sb.append("(pid ").append(event.getPointerId(i)); 105 sb.append(")=").append((int) event.getX(i)); 106 sb.append(",").append((int) event.getY(i)); 107 if (i + 1 < event.getPointerCount()) 108 sb.append(";"); 109 } 110 sb.append("]"); 111 //Log.d(TAG, sb.toString()); 112 } 113 114 115 private float spacing(MotionEvent event) { 116 float x = event.getX(0) - event.getX(1); 117 float y = event.getY(0) - event.getY(1); 118 return FloatMath.sqrt(x * x + y * y); 119 } 120 121 122 private void midPoint(PointF point, MotionEvent event) { 123 float x = event.getX(0) + event.getX(1); 124 float y = event.getY(0) + event.getY(1); 125 point.set(x / 2, y / 2); 126 } 127 128 129 }