Android實現對imageview的拖動以及縮放

Android實現對imageview的拖動以及縮放

1. package org.wch.gesture;
3. import android.graphics.Matrix;
4. import android.graphics.PointF;
5. import android.util.FloatMath;
6. import android.util.Log;
7. import android.view.MotionEvent;
8. import android.view.View;
9. import android.view.View.OnTouchListener;
10. import android.widget.ImageView;
11. import android.widget.ImageView.ScaleType;
13. public class MulitPointTouchListener implements OnTouchListener {
15. Matrix matrix = new Matrix();
16. Matrix savedMatrix = new Matrix();
18. public ImageView image;
19. static final int NONE = 0;
20. static final int DRAG = 1;
21. static final int ZOOM = 2;
22. int mode = NONE;
24. PointF start = new PointF();
25. PointF mid = new PointF();
26. float oldDist = 1f;
29. public MulitPointTouchListener(ImageView image) {
30. super();
31. this.image = image;
32. }
34. @Override
35. public boolean onTouch(View v, MotionEvent event) {
36. this.image.setScaleType(ScaleType.MATRIX);
38. ImageView view = (ImageView) v;
39. // dumpEvent(event);
41. switch (event.getAction() & MotionEvent.ACTION_MASK) {
43. case MotionEvent.ACTION_DOWN:
45. Log.w("FLAG", "ACTION_DOWN");
46. matrix.set(view.getImageMatrix());
47. savedMatrix.set(matrix);
48. start.set(event.getX(), event.getY());
49. mode = DRAG;
50. break;
51. case MotionEvent.ACTION_POINTER_DOWN:
52. Log.w("FLAG", "ACTION_POINTER_DOWN");
53. oldDist = spacing(event);
54. if (oldDist > 10f) {
55. savedMatrix.set(matrix);
56. midPoint(mid, event);
57. mode = ZOOM;
58. }
59. break;
60. case MotionEvent.ACTION_UP:
61. Log.w("FLAG", "ACTION_UP");
62. case MotionEvent.ACTION_POINTER_UP:
63. Log.w("FLAG", "ACTION_POINTER_UP");
64. mode = NONE;
65. break;
66. case MotionEvent.ACTION_MOVE:
67. Log.w("FLAG", "ACTION_MOVE");
68. if (mode == DRAG) {
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. if (newDist > 10f) {
75. matrix.set(savedMatrix);
76. float scale = newDist / oldDist;
77. matrix.postScale(scale, scale, mid.x, mid.y);
78. }
79. }
80. break;
81. }
83. view.setImageMatrix(matrix);
84. return true;
85. }
88. private float spacing(MotionEvent event) {
89. float x = event.getX(0) - event.getX(1);
90. float y = event.getY(0) - event.getY(1);
91. return FloatMath.sqrt(x * x + y * y);
92. }
94. private void midPoint(PointF point, MotionEvent event) {
95. float x = event.getX(0) + event.getX(1);
96. float y = event.getY(0) + event.getY(1);
97. point.set(x / 2, y / 2);
98. }
99. }