Android SurfaceView学习示范

Android SurfaceView学习示例

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View，是Android的一个超类，这个类几乎包含了所有的屏幕类型。每一个View都有一个用于绘图的画布，这个画布可以进行任意扩展。

在游戏开发中叶可以自定义视图(View)，这个画布的功能更能满足我们在游戏开发中的需要。在Android中，任何一个View类都只需重写onDraw 方法来实现界面显示，自定义的视图可以是复杂的3D实现，也可以是非常简单的文本形式等。?

游戏的核心是不断地绘图和刷新界面，Android中提供了 invalidate 方法来实现界面刷新。注意，invalidate 不能直接在线程中调用， 就是不可以在子线程中调用，因此它违背了 Android的单线程模型：Android UI操作并不是线程安全的，并且这些操作必须在UI 线程中执行，因此Android中最常用的方法就是利用Handler来实现UI线程的更新。 其实用 AsyncTask 也可以。

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具体示例：

Activity：

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1. public?class?Activity01?extends?Activity?{??
2. ??????
3. ????private?static?final?String?TAG?=?"mThread";??
4. ????private?static?final?int?REFRESH?=?0x000001;??
5. ????private?GameView?mGameView?=?null;??
6. ??
7. ????@Override??
8. ????public?void?onCreate(Bundle?savedInstanceState)?{??
9. ????????super.onCreate(savedInstanceState);??
10. ??????????
11. ????????this.mGameView?=?new?GameView(this);??
12. ????????mGameView.x?=?320.0f;??
13. ????????mGameView.y?=?120.0f;??
14. ????????setContentView(mGameView);??
15. ??????????
16. ????????new?Thread(new?GameThread()).start();??
17. ????}??
18. ??
19. ????Handler?myHandler?=?new?Handler()?{??
20. ??????????
21. ????????@Override??
22. ????????public?void?handleMessage(Message?msg)?{??
23. ??
24. ????????????switch?(msg.what)?{??
25. ????????????case?Activity01.REFRESH:??
26. ????????????????mGameView.invalidate();?????//?repaint?View??
27. ????????????????break;??
28. ????????????}??
29. ????????????super.handleMessage(msg);??
30. ????????}??
31. ????};??
32. ??????
33. ????class?GameThread?implements?Runnable?{??
34. ??????????
35. ????????@Override??
36. ????????public?void?run()?{??
37. ????????????while?(!Thread.currentThread().isInterrupted())?{??
38. ????????????????Message?message?=?new?Message();??
39. ????????????????message.what?=?Activity01.REFRESH;??
40. ??????????????????
41. ????????????????Activity01.this.myHandler.sendMessage(message);??
42. ????????????????try?{??
43. ????????????????????Thread.sleep(1000);??
44. ????????????????}?catch?(InterruptedException?e)?{??
45. ????????????????????Thread.currentThread().interrupt();??
46. ????????????????}??
47. ????????????}??
48. ????????}??
49. ????}??
50. ??
51. ????@Override??
52. ????public?boolean?onTouchEvent(MotionEvent?event)?{??
53. ????????if(event.getAction()?==?MotionEvent.ACTION_DOWN){??
54. ????????????mGameView.x?=?event.getX();??
55. ????????????mGameView.y?=?event.getY();??
56. ????????}??
57. ??????????
58. ????????return?true;??
59. ????}??
60. ??????
61. ????@Override??
62. ????public?boolean?onKeyDown(int?keyCode,?KeyEvent?event)?{??
63. ????????if(keyCode?==?KeyEvent.KEYCODE_BACK){??
64. ????????????this.finish();??
65. ????????}??
66. ??????????
67. ????????return?true;??
68. ????}??
69. }??

gameview

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1. public?class?GameView?extends?View?{??
2. ????int?count?=?0;??
3. ????float?x?=?0,?y?=?0;??
4. ??
5. ????public?GameView(Context?context)?{??
6. ????????super(context);??
7. ????}??
8. ??
9. ????public?void?onDraw(Canvas?canvas)?{??
10. ????????if?(count?<?100)?{??
11. ????????????count++;??
12. ????????}?else?{??
13. ????????????count?=?0;??
14. ????????}??
15. ??
16. ????????Paint?mPaint?=?new?Paint();??
17. ????????switch?(count?%?4)?{??
18. ????????case?0:??
19. ????????????mPaint.setColor(Color.BLUE);??
20. ????????????break;??
21. ????????case?1:??
22. ????????????mPaint.setColor(Color.GREEN);??
23. ????????????break;??
24. ????????case?2:??
25. ????????????mPaint.setColor(Color.RED);??
26. ????????????break;??
27. ????????case?3:??
28. ????????????mPaint.setColor(Color.YELLOW);??
29. ????????????break;??
30. ????????default:??
31. ????????????mPaint.setColor(Color.WHITE);??
32. ????????????break;??
33. ????????}??
34. ??
35. ????????canvas.drawRect(x?-?40,?y?-?20,?x?+?40,?y?+?20,?mPaint);??
36. ????}??
37. }??

运行效果：

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