Android控件拖動的實現【源碼】

這個也是從網上得到的Android代碼，例子比較簡單，但是如果有需要此功能的，這個例子可以提供很多提示，首先，給個截圖

這個是拖動以後的效果，一個imageview和一個button控件，提供兩份代碼下載吧，一份是只有一個Button的，另一份就是像上圖，就是多了一個imagview！先看下代碼吧，比較簡單：

1. public class DraftTest extends Activity implements OnTouchListener{
2. /** Called when the activity is first created. */
3. int screenWidth;
4. int screenHeight;
5. int lastX;
6. int lastY;
7. @Override
8. public void onCreate(Bundle savedInstanceState) {
9. super.onCreate(savedInstanceState);
10. setContentView(R.layout.main);
12. DisplayMetrics dm = getResources().getDisplayMetrics();
13. screenWidth = dm.widthPixels;
14. screenHeight = dm.heightPixels - 50;
15. Button button=(Button)findViewById(R.id.btn);
16. ImageView imageView=(ImageView)findViewById(R.id.btn2);
17. imageView.setOnTouchListener(this);
18. button.setOnTouchListener(this);
19. }
21. @Override
22. public boolean onTouch(View v, MotionEvent event) {
23. // TODO Auto-generated method stub
24. int action=event.getAction();
25. Log.i("@@@@@@", "Touch:"+action);
26. //Toast.makeText(DraftTest.this, "λ�ã�"+x+","+y, Toast.LENGTH_SHORT).show();
27. switch(action){
28. case MotionEvent.ACTION_DOWN:
29. lastX = (int) event.getRawX();
30. lastY = (int) event.getRawY();
31. break;
32. /**
33. * layout(l,t,r,b)
34. * l Left position, relative to parent
35. t Top position, relative to parent
36. r Right position, relative to parent
37. b Bottom position, relative to parent
38. * */
39. case MotionEvent.ACTION_MOVE:
40. int dx =(int)event.getRawX() - lastX;
41. int dy =(int)event.getRawY() - lastY;
43. int left = v.getLeft() + dx;
44. int top = v.getTop() + dy;
45. int right = v.getRight() + dx;
46. int bottom = v.getBottom() + dy;
47. if(left < 0){
48. left = 0;
49. right = left + v.getWidth();
50. }
51. if(right > screenWidth){
52. right = screenWidth;
53. left = right - v.getWidth();
54. }
55. if(top < 0){
56. top = 0;
57. bottom = top + v.getHeight();
58. }
59. if(bottom > screenHeight){
60. bottom = screenHeight;
61. top = bottom - v.getHeight();
62. }
63. v.layout(left, top, right, bottom);
64. Log.i("@@@@@@", "position��" + left +", " + top + ", " + right + ", " + bottom);
65. lastX = (int) event.getRawX();
66. lastY = (int) event.getRawY();
67. break;
68. case MotionEvent.ACTION_UP:
69. break;
70. }
71. return false;
72. }
73. }