SurfaceView双缓冲Demo

浅浅的花香味﹌ 2022-08-05 04:17 114阅读 0赞

最近在使用SurfaceView时发现出现了闪烁现象，上网查询一番，发现是由于SurfaceView的双缓冲机制造成的。关于理论部分，《[Surface的一些说明][Surface]》说明的很透彻，这里就不再重复了，这里用一个具体的例子在其内容进行补充，希望对大家有所帮助。

先看这段代码：

**\[java\]** [view plain][] [copy][view plain]

1.  **package** com.david.surfaceview; 
2.  
3.  **import** java.util.Random; 
4.  
5.  **import** android.content.Context; 
6.  **import** android.graphics.Bitmap; 
7.  **import** android.graphics.Canvas; 
8.  **import** android.graphics.Color; 
9.  **import** android.graphics.Paint; 
10. **import** android.graphics.Paint.Style; 
11. **import** android.util.AttributeSet; 
12. **import** android.util.Log; 
13. **import** android.view.KeyEvent; 
14. **import** android.view.SurfaceHolder; 
15. **import** android.view.SurfaceView; 
16. 
17. **public****class** DoubleSurfaceViewFlicker **extends** SurfaceView **implements**
18.  SurfaceHolder.Callback \{ 
19. 
20. **private****final****static** String TAG = "DoubleSurfaceViewFlicker"; 
21. **private** SurfaceHolder shd; 
22. 
23. **public** DoubleSurfaceViewFlicker(Context context) \{ 
24. **super**(context); 
25.  init(); 
26.  \} 
27. 
28. **public** DoubleSurfaceViewFlicker(Context context, AttributeSet attrs) \{ 
29. **super**(context, attrs); 
30.  init(); 
31.  \} 
32. 
33. **public** DoubleSurfaceViewFlicker(Context context, AttributeSet attrs, 
34. **int** defStyle) \{ 
35. **super**(context, attrs, defStyle); 
36.  init(); 
37.  \} 
38. 
39. **void** init() \{ 
40.  shd = **this**.getHolder(); 
41.  shd.addCallback(**this**); 
42.  \} 
43. 
44. @Override
45. **public****void** surfaceChanged(SurfaceHolder holder, **int** format, **int** width, 
46. **int** height) \{ 
47. 
48.  \} 
49. 
50. @Override
51. **public****void** surfaceCreated(SurfaceHolder holder) \{ 
52.  width = **this**.getWidth(); 
53.  height = **this**.getHeight(); 
54. 
55.  board = Bitmap.createBitmap(**this**.getWidth(), **this**.getHeight(), 
56.  Bitmap.Config.ARGB\_8888); 
57.  boardCanvas = **new** Canvas(board); 
58. 
59.  paint = **new** Paint(); 
60.  paint.setStyle(Style.FILL); 
61.  paint.setAntiAlias(**true**); 
62. 
63.  drawThread.start(); 
64.  \} 
65. 
66. @Override
67. **public****void** surfaceDestroyed(SurfaceHolder holder) \{ 
68.  isRunning = **false**; 
69.  Log.e(TAG, "\*\*\* surfaceDestroyed \*\*\*"); 
70.  \} 
71. 
72. **private****int** width; 
73. **private****int** height; 
74. **private** Boolean isRunning = **true**; 
75. **public****void** setIsRunning(Boolean isRunning) \{ 
76. **this**.isRunning = isRunning; 
77.  \} 
78. 
79. **private** Paint paint; 
80. **private****int** i = 0; 
81. 
82.  Bitmap board = **null**; 
83.  Canvas boardCanvas = **null**; 
84. 
85.  Thread drawThread = **new** Thread() \{ 
86. 
87. **public****void** run() \{ 
88. **while** (isRunning) \{ 
89. **long** startTime = System.currentTimeMillis(); 
90.  Random random = **new** Random(System.currentTimeMillis()); 
91.  Canvas canvas = **null**; 
92. 
93. **try** \{ 
94.  paint.setColor(Color.rgb(random.nextInt(255), 
95.  random.nextInt(255), random.nextInt(255))); 
96.  paint.setStrokeWidth(4); 
97.  paint.setTextSize(40); 
98. 
99.  String text = "" \+ i + ""; 
100.  i++; 
101. 
102.  canvas = shd.lockCanvas(); 
103. **if** (canvas != **null** && board != **null**) \{ 
104.  canvas.drawText(text, width/2, height/2, paint); 
105.  \} 
106. 
107.  Thread.sleep(1000); 
108.  \} **catch** (Exception e) \{ 
109.  e.printStackTrace(); 
110.  \} **finally** \{ 
111. **if** (shd != **null** && canvas != **null**) \{ 
112.  shd.unlockCanvasAndPost(canvas); 
113.  \} 
114. **long** endTime = System.currentTimeMillis(); 
115.  Log.e(TAG, "\*\*\* 2 spend time: " \+ (endTime-startTime)); 
116.  \} 
117.  \} 
118.  \}; 
119.  \}; 
120. 
121. \}

运行它，大家会发现单数显示在一个画面，双数显示在一个画面，这就是因为SurfaceView的双缓冲机制造成的。因为SurfaceView的2个缓冲区A和B是轮流显示的，所以 单数显示在一个画面，双数显示在一个画面。

解决的方法如下：

**\[java\]** [view plain][] [copy][view plain]

1.  **package** com.david.surfaceview; 
2.  
3.  **import** java.util.Date; 
4.  **import** java.util.Random; 
5.  
6.  **import** android.content.Context; 
7.  **import** android.graphics.Bitmap; 
8.  **import** android.graphics.Canvas; 
9.  **import** android.graphics.Color; 
10. **import** android.graphics.Paint; 
11. **import** android.graphics.Paint.Style; 
12. **import** android.graphics.Path; 
13. **import** android.util.AttributeSet; 
14. **import** android.util.Log; 
15. **import** android.view.KeyEvent; 
16. **import** android.view.SurfaceHolder; 
17. **import** android.view.SurfaceView; 
18. 
19. **public****class** DoubleSurfaceView **extends** SurfaceView **implements**
20.  SurfaceHolder.Callback \{ 
21. **private****final****static** String TAG = "DoubleSurfaceView"; 
22. **private** SurfaceHolder shd; 
23. 
24. **public** DoubleSurfaceView(Context context) \{ 
25. **super**(context); 
26.  init(); 
27.  \} 
28. 
29. **public** DoubleSurfaceView(Context context, AttributeSet attrs) \{ 
30. **super**(context, attrs); 
31.  init(); 
32.  \} 
33. 
34. **public** DoubleSurfaceView(Context context, AttributeSet attrs, **int** defStyle) \{ 
35. **super**(context, attrs, defStyle); 
36.  init(); 
37.  \} 
38. 
39. **void** init() \{ 
40.  shd = **this**.getHolder(); 
41.  shd.addCallback(**this**); 
42.  \} 
43. 
44. @Override
45. **public****void** surfaceChanged(SurfaceHolder holder, **int** format, **int** width, 
46. **int** height) \{ 
47. 
48.  \} 
49. 
50. @Override
51. **public****void** surfaceCreated(SurfaceHolder holder) \{ 
52.  width = **this**.getWidth(); 
53.  height = **this**.getHeight(); 
54. 
55.  board = Bitmap.createBitmap(**this**.getWidth(), **this**.getHeight(), 
56.  Bitmap.Config.ARGB\_8888); 
57.  boardCanvas = **new** Canvas(board); 
58. 
59.  paint = **new** Paint(); 
60.  paint.setStyle(Style.FILL); 
61.  paint.setAntiAlias(**true**); 
62. 
63.  drawThread.start(); 
64.  \} 
65. 
66. @Override
67. **public****void** surfaceDestroyed(SurfaceHolder holder) \{ 
68.  isRunning = **false**; 
69.  \} 
70. 
71. **private****int** width; 
72. **private****int** height; 
73. **private** Boolean isRunning = **true**; 
74. **public****void** setIsRunning(Boolean isRunning) \{ 
75. **this**.isRunning = isRunning; 
76.  \} 
77. 
78. **private** Paint paint; 
79. **private****int** i = 0; 
80. 
81.  Bitmap board = **null**; 
82.  Canvas boardCanvas = **null**; 
83. 
84.  Thread drawThread = **new** Thread() \{ 
85. 
86. **public****void** run() \{ 
87. **while** (isRunning) \{ 
88. **long** startTime = System.currentTimeMillis(); 
89.  Random random = **new** Random(System.currentTimeMillis()); 
90.  Canvas canvas = **null**; 
91. 
92. **try** \{ 
93.  paint.setColor(Color.rgb(random.nextInt(255), 
94.  random.nextInt(255), random.nextInt(255))); 
95.  paint.setStrokeWidth(4); 
96.  paint.setTextSize(40); 
97. 
98.  String text = "" \+ i + ""; 
99.  boardCanvas.drawText(text, width/2, height/2, paint); 
100.  i++; 
101. 
102.  canvas = shd.lockCanvas(); 
103. **if** (canvas!=**null** && board!=**null**) \{ 
104.  canvas.drawBitmap(board, 0, 0, **null**); 
105.  \} 
106. 
107.  Thread.sleep(1000); 
108.  \} **catch** (Exception e) \{ 
109.  e.printStackTrace(); 
110.  \} **finally** \{ 
111. **if** (shd != **null** && canvas != **null**) \{ 
112.  shd.unlockCanvasAndPost(canvas); 
113.  \} 
114. **long** endTime = System.currentTimeMillis(); 
115.  Log.e(TAG, "\*\*\* 1 spend time: " \+ (endTime-startTime)); 
116.  \} 
117.  \} 
118.  \}; 
119.  \}; 
120. 
121. \}

这里我将所有的绘画内容都画在board里，然后使用canvas绘制board，以保证SurfaceView的2个缓冲区的内容一致，所以没有闪烁现象发生

转载于：http://blog.csdn.net/imyfriend/article/details/8033823

[Surface]: http://blog.csdn.net/imyfriend/article/details/7922838
[view plain]: http://blog.csdn.net/imyfriend/article/details/8033823#