sendStickyBroadcast和sendStickyOrderedBroadcast - 牛仔的移動(dòng)開發(fā)博客 - 博客頻道 - CSDN.NET

sendStickyBroadcast和sendStickyOrderedBroadcast發(fā)出的廣播會(huì)一直滯留（等待），以便有人注冊(cè)這則廣播消息后能盡快的收到這條廣播。其他功能與sendBroadcast相同。但是使用sendStickyBroadcast 發(fā)送廣播需要獲得BROADCAST_STICKY?permission，如果沒有這個(gè)permission則會(huì)拋出異常。

?

例子：

[java]?view plaincopyprint?

1. package?com.android.test;??
2. ??
3. import?android.app.Activity;??
4. import?android.content.Context;??
5. import?android.content.Intent;??
6. import?android.os.Bundle;??
7. import?android.view.View;??
8. import?android.view.View.OnClickListener;??
9. import?android.widget.Button;??
10. ??
11. public?class?StickyBroadcastTest?extends?Activity?{??
12. ???
13. ?private?Button?mSendBroadcast;??
14. ?private?Button?mSendStickyBroadcast;??
15. ?private?Button?mNextActivity;??
16. ?private?Context?mContext;??
17. ???
18. ?private?int?mStickyBrcCount;??
19. ????
20. ????/**?Called?when?the?activity?is?first?created.?*/??
21. ????@Override??
22. ????public?void?onCreate(Bundle?savedInstanceState)?{??
23. ????????super.onCreate(savedInstanceState);??
24. ????????setContentView(R.layout.main);??
25. ????????mContext?=?getApplicationContext();??
26. ????????mSendBroadcast?=?(Button)findViewById(R.id.broadcast);??
27. ????????mSendStickyBroadcast?=?(Button)findViewById(R.id.stickybroadcast);??
28. ????????mNextActivity?=?(Button)findViewById(R.id.next_activity);??
29. ??????????
30. ????????mSendBroadcast.setOnClickListener(new?OnClickListener()?{??
31. ?????
32. ???@Override??
33. ???public?void?onClick(View?v)?{??
34. ??????
35. ????Intent?intent?=?new?Intent("com.android.action.broadcast");??
36. ????mContext.sendBroadcast(intent);??
37. ???}??
38. ??});??
39. ??????????
40. ????????mSendStickyBroadcast.setOnClickListener(new?OnClickListener()?{??
41. ?????
42. ???@Override??
43. ???public?void?onClick(View?v)?{??
44. ????mStickyBrcCount++;??
45. ????Intent?intent?=?new?Intent("com.android.action.sticky.broadcast");??
46. ????intent.putExtra("sent_count",?mStickyBrcCount);??
47. ????mContext.sendStickyBroadcast(intent);??
48. ??????
49. ???}??
50. ??});????
51. ????????mNextActivity.setOnClickListener(new?OnClickListener()?{??
52. ?????
53. ???@Override??
54. ???public?void?onClick(View?v)?{??
55. ????Intent?intent?=?new?Intent(StickyBroadcastTest.this,?MyReceiverActivity.class);??
56. ????startActivity(intent);?????
57. ??????
58. ???}??
59. ??});??
60. ????}??
61. ??
62. ?@Override??
63. ?protected?void?onResume()?{??
64. ??//?TODO?Auto-generated?method?stub???
65. ??super.onResume();??
66. ??mStickyBrcCount?=?0;??
67. ?}??
68. ?????
69. }??
70. ??
71. ???
72. //MyReceiverActivity????
73. package?com.android.test;??
74. ??
75. import?android.app.Activity;??
76. import?android.content.BroadcastReceiver;??
77. import?android.content.Context;??
78. import?android.content.Intent;??
79. import?android.content.IntentFilter;??
80. import?android.os.Bundle;??
81. import?android.util.Log;??
82. ??
83. public?class?MyReceiverActivity?extends?Activity?{??
84. ??
85. ?private?IntentFilter?mIntentFilter;??
86. ?private?final?static?String?TAG?=?"MyReceiverActivity";??
87. ????/**?Called?when?the?activity?is?first?created.?*/??
88. ????@Override??
89. ????public?void?onCreate(Bundle?savedInstanceState)?{??
90. ????????super.onCreate(savedInstanceState);??
91. ????????setContentView(R.layout.broadcast_receiver);??
92. ??????????
93. ????????mIntentFilter?=?new?IntentFilter();?????
94. ????????mIntentFilter.addAction("com.android.action.broadcast");?????
95. ????????mIntentFilter.addAction("com.android.action.sticky.broadcast");?????
96. ??
97. ????}??
98. ???????
99. ?private?BroadcastReceiver??mReceiver?=?new?BroadcastReceiver?()?{??
100. ??@Override??
101. ??public?void?onReceive(Context?context,?Intent?intent)?{??
102. ???final?String?action?=?intent.getAction();??
103. ???int?count?=?intent.getIntExtra("sent_count",?-1);??
104. ???Log.d(TAG,?"action?=?"?+?action?+?"and?count?=?"?+?count);??
105. ?????
106. ???//context.removeStickyBroadcast(intent);???
107. ??}??
108. ?};??
109. ??
110. ?@Override??
111. ?protected?void?onPause()?{??
112. ??//?TODO?Auto-generated?method?stub???
113. ??super.onPause();??
114. ??unregisterReceiver(mReceiver);?????
115. ??
116. ?}???
117. ??
118. ?@Override??
119. ?protected?void?onResume()?{??
120. ??//?TODO?Auto-generated?method?stub?????
121. ??super.onResume();??
122. ??registerReceiver(mReceiver,?mIntentFilter);???
123. ?}??
124. ?????
125. }??

運(yùn)行結(jié)果如圖：

首先點(diǎn)擊next Activity從代碼中可以看到receiver已經(jīng)注冊(cè)，但Log無輸出，這是當(dāng)然的了~~~因?yàn)闆]有廣播發(fā)出自然就不會(huì)有人響應(yīng)了。（onPause里unregisterReceiver了）

按back后退到上圖

下面分別點(diǎn)擊send broadcast 和 send stickybroadcast按鈕，隨便點(diǎn)擊幾次，此時(shí)對(duì)應(yīng)的receiver并沒有注冊(cè)，所以是不會(huì)有人響應(yīng)這兩條廣播的。然后點(diǎn)擊next activity，當(dāng)打開新的activity后對(duì)應(yīng)的receiver被注冊(cè)，此時(shí)從日志中就能看出已經(jīng)收到了send stickybroadcast發(fā)出的廣播，但沒有send broadcast發(fā)出的廣播。這就是sendStickyBroadcast的特別之處，它將發(fā)出的廣播保存起來，一旦發(fā)現(xiàn)有人注冊(cè)這條廣播，則立即能接收到。

日志打印為： action = com.android.action.sticky.broadcastand count = 4

從上面的日志信息可以看出sendStickyBroadcast只保留最后一條廣播，并且一直保留下去，這樣即使已經(jīng)處理了這條廣播但當(dāng)再一次注冊(cè)這條廣播后依然可以收到它。

如果你只想處理一遍，removeStickyBroadcast方法可以幫你，處理完了后就將它刪除吧。

?

sticky形式的intent，接收者可以為空,接收者為空時(shí)，通常是獲取最后一個(gè)保存廣播的intent，從而獲取intent里的值，不如獲取電池的電量：

因?yàn)锽atteryManager發(fā)送的是sticky形式的intent，所以接收者可以為空?
Intent batteryStatus = registerReceiver(null, ifilter);?

//得到電池當(dāng)前的狀態(tài)（共有5種，包括unkonwn、charging、discharging、not charging、full）?
int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);?
//是否處于充電狀態(tài)?
boolean isCharging = ?BatteryManager.BATTERY_STATUS_CHARGING ;

轉(zhuǎn)載于:https://www.cnblogs.com/seven1979/p/4333070.html

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