Android實現對imageview的拖動以及縮放
- package org.wch.gesture;
-
- import android.graphics.Matrix;
- import android.graphics.PointF;
- import android.util.FloatMath;
- import android.util.Log;
- import android.view.MotionEvent;
- import android.view.View;
- import android.view.View.OnTouchListener;
- import android.widget.ImageView;
- import android.widget.ImageView.ScaleType;
-
- public class MulitPointTouchListener implements OnTouchListener {
-
- Matrix matrix = new Matrix();
- Matrix savedMatrix = new Matrix();
-
- public ImageView image;
- static final int NONE = 0;
- static final int DRAG = 1;
- static final int ZOOM = 2;
- int mode = NONE;
-
- PointF start = new PointF();
- PointF mid = new PointF();
- float oldDist = 1f;
-
-
- public MulitPointTouchListener(ImageView image) {
- super();
- this.image = image;
- }
-
- @Override
- public boolean onTouch(View v, MotionEvent event) {
- this.image.setScaleType(ScaleType.MATRIX);
-
- ImageView view = (ImageView) v;
- // dumpEvent(event);
-
- switch (event.getAction() & MotionEvent.ACTION_MASK) {
-
- case MotionEvent.ACTION_DOWN:
-
- Log.w("FLAG", "ACTION_DOWN");
- matrix.set(view.getImageMatrix());
- savedMatrix.set(matrix);
- start.set(event.getX(), event.getY());
- mode = DRAG;
- break;
- case MotionEvent.ACTION_POINTER_DOWN:
- Log.w("FLAG", "ACTION_POINTER_DOWN");
- oldDist = spacing(event);
- if (oldDist > 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);
- }
- }