Android 兩點縮放圖片

Android 兩點縮放圖片：

本文工程源碼下載：

免費下載地址在 http://linux.linuxidc.com/

用戶名與密碼都是www.linuxidc.com

具體下載目錄在 /pub/Android源碼集錦/2011年/11月/Android 兩點縮放圖片/

1. package mutl.touch.sample;
3. import android.app.Activity;
4. import android.graphics.Matrix;
5. import android.graphics.PointF;
6. import android.os.Bundle;
7. import android.util.FloatMath;
8. import android.view.MotionEvent;
9. import android.view.View;
10. import android.view.View.OnTouchListener;
11. import android.widget.ImageView;
13. public class Main extends Activity
14. {
15. private static final int NONE = 0;
16. private static final int DRAG = 1;
17. private static final int ZOOM = 2;
19. private int mode = NONE;
20. private float oldDist;
21. private Matrix matrix = new Matrix();
22. private Matrix savedMatrix = new Matrix();
23. private PointF start = new PointF();
24. private PointF mid = new PointF();
26. @Override
27. public void onCreate(Bundle savedInstanceState)
28. {
29. super.onCreate(savedInstanceState);
30. setContentView(R.layout.main);
31. ImageView view = (ImageView) findViewById(R.id.image_view);
32. view.setOnTouchListener(new OnTouchListener()
33. {
34. @Override
35. public boolean onTouch(View v, MotionEvent event)
36. {
37. ImageView view = (ImageView) v;
38. switch (event.getAction() & MotionEvent.ACTION_MASK)
39. {
40. case MotionEvent.ACTION_DOWN:
41. savedMatrix.set(matrix);
42. start.set(event.getX(), event.getY());
43. mode = DRAG;
44. break;
45. case MotionEvent.ACTION_UP:
46. case MotionEvent.ACTION_POINTER_UP:
47. mode = NONE;
48. break;
49. case MotionEvent.ACTION_POINTER_DOWN:
50. oldDist = spacing(event);
51. if (oldDist > 10f)
52. {
53. savedMatrix.set(matrix);
54. midPoint(mid, event);
55. mode = ZOOM;
56. }
57. break;
58. case MotionEvent.ACTION_MOVE:
59. if (mode == DRAG)
60. {
61. matrix.set(savedMatrix);
62. matrix.postTranslate(event.getX() - start.x,
63. event.getY() - start.y);
64. }
65. else if (mode == ZOOM)
66. {
67. float newDist = spacing(event);
68. if (newDist > 10f)
69. {
70. matrix.set(savedMatrix);
71. float scale = newDist / oldDist;
72. matrix.postScale(scale, scale, mid.x, mid.y);
73. }
74. }
75. break;
76. }
77. // 圖片設置矩陣
78. view.setImageMatrix(matrix);
79. return true;
80. }
82. private float spacing(MotionEvent event)
83. {
84. float x = event.getX(0) - event.getX(1);
85. float y = event.getY(0) - event.getY(1);
86. return FloatMath.sqrt(x * x + y * y);
87. }
89. private void midPoint(PointF point, MotionEvent event)
90. {
91. float x = event.getX(0) + event.getX(1);
92. float y = event.getY(0) + event.getY(1);
93. point.set(x / 2, y / 2);
94. }
95. });
96. }
97. }