MulitPointTouchListener.java

package com.mzeat.ui.widget;

import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class MulitPointTouchListener  implements OnTouchListener {
	 private static final String TAG = "Touch";
     // These matrices will be used to move and zoom image
     Matrix matrix = new Matrix();
     Matrix savedMatrix = new Matrix();

     // We can be in one of these 3 states
     static final int NONE = 0;
     static final int DRAG = 1;
     static final int ZOOM = 2;
     int mode = NONE;

     // Remember some things for zooming
     PointF start = new PointF();
     PointF mid = new PointF();
     float oldDist = 1f;

     @Override
     public boolean onTouch(View v, MotionEvent event) {

             ImageView view = (ImageView) v;
             // Log.e("view_width",
             // view.getImageMatrix()..toString()+"*"+v.getWidth());
             // Dump touch event to log
             dumpEvent(event);

             // Handle touch events here...
             switch (event.getAction() & MotionEvent.ACTION_MASK) {
             case MotionEvent.ACTION_DOWN:

                     matrix.set(view.getImageMatrix());
                     savedMatrix.set(matrix);
                     start.set(event.getX(), event.getY());
                     //Log.d(TAG, "mode=DRAG");
                     mode = DRAG;

                    
                     //Log.d(TAG, "mode=NONE");
                     break;
             case MotionEvent.ACTION_POINTER_DOWN:
                     oldDist = spacing(event);
                     //Log.d(TAG, "oldDist=" + oldDist);
                     if (oldDist > 10f) {
                             savedMatrix.set(matrix);
                             midPoint(mid, event);
                             mode = ZOOM;
                             //Log.d(TAG, "mode=ZOOM");
                     }
                     break;
             case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_POINTER_UP:
                     mode = NONE;
                     //Log.e("view.getWidth", view.getWidth() + "");
                     //Log.e("view.getHeight", view.getHeight() + "");

                     break;
             case MotionEvent.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);
                             //Log.d(TAG, "newDist=" + newDist);
                             if (newDist > 10f) {
                                     matrix.set(savedMatrix);
                                     float scale = newDist / oldDist;
                                     matrix.postScale(scale, scale, mid.x, mid.y);
                             }
                     }
                     break;
             }

             view.setImageMatrix(matrix);
             return true; // indicate event was handled
     }

     private void dumpEvent(MotionEvent event) {
             String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
                             "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
             StringBuilder sb = new StringBuilder();
             int action = event.getAction();
             int actionCode = action & MotionEvent.ACTION_MASK;
             sb.append("event ACTION_").append(names[actionCode]);
             if (actionCode == MotionEvent.ACTION_POINTER_DOWN
                             || actionCode == MotionEvent.ACTION_POINTER_UP) {
                     sb.append("(pid ").append(
                                     action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
                     sb.append(")");
             }
             sb.append("[");
             for (int i = 0; i < event.getPointerCount(); i++) {
                     sb.append("#").append(i);
                     sb.append("(pid ").append(event.getPointerId(i));
                     sb.append(")=").append((int) event.getX(i));
                     sb.append(",").append((int) event.getY(i));
                     if (i + 1 < event.getPointerCount())
                             sb.append(";");
             }
             sb.append("]");
             //Log.d(TAG, sb.toString());
     }

    
     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);
     }
}