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1.廣播接收者
廣播接收者簡單地說就是接收廣播意圖的Java類，此Java類繼承BroadcastReceiver類，重寫：
public void onReceive(Context context,Intent intent)，其中intent可以獲得傳遞的數(shù)據(jù)；
廣播意圖就是通過Context.sendBroadcast(Intent intent)或Context.sendOrderedBroadcast(Intent intent)發(fā)送的意圖，通過這個語句，能夠廣播給所有滿足條件的組件，比如intent設(shè)置了action="com.xiazdong",則所有在AndroidManifest.xml中設(shè)置過<action android:name="com.xiazdong"/>的廣播接收者都能夠接收到廣播；
注：onReceive方法必須在10秒內(nèi)完成，如果沒有完成，則拋“Application No Response”當(dāng)廣播接收者onReceive方法需要執(zhí)行很長時間時，最好將此耗時工作通過Intent發(fā)送給Service，由Service完成，并且不能使用子線程解決，因為BroadcastReceiver是接收到廣播后才創(chuàng)建的，并且生命周期很短，因此子線程可能在沒有執(zhí)行完就已經(jīng)被殺死了。
[java]?view plaincopy
public?void?onReceive(Context?context,Intent?intent){??
????Intent?intent?=?new?Intent(context,XxxService.class);??
????context.startService(intent);??
}??
2.廣播發(fā)送者
通常廣播發(fā)送方就是調(diào)用Context.sendBroadcast()的程序，而廣播接收者就是繼承BroadcastReceiver的程序；
通常廣播發(fā)送方都是通過隱式意圖，這樣才能發(fā)送給多人；
廣播發(fā)送方分為普通廣播和有序廣播；
同步廣播：發(fā)送方發(fā)出后，幾乎同時到達(dá)多個廣播接收者處，某個接收者不能接收到廣播后進(jìn)行一番處理后傳給下一個接收者，并且無法終止廣播繼續(xù)傳播；Context.sendBroadcast(intent);
有序廣播：廣播接收者需要提前設(shè)置優(yōu)先級，優(yōu)先級高的先接收到廣播，優(yōu)先級數(shù)值為-1000~1000，在AndroidManifest.xml的<intent-filter android:priority="xxx">設(shè)置；比如存在3個廣播接收者A、B、C，優(yōu)先級A>B>C,因此A最先收到廣播，當(dāng)A收到廣播后，可以向廣播中添加一些數(shù)據(jù)給下一個接收者(intent.putExtra())，或者終止廣播(abortBroadcast())；Context.sendOrderedBroadcast(intent);
二、廣播接收者核心代碼
同步廣播發(fā)送方核心代碼：
[java]?view plaincopy
Intent?intent?=?new?Intent();??
intent.setAction("...");??
Context.sendBroadcast(intent);??
有序廣播發(fā)送方核心代碼：
[java]?view plaincopy
Intent?intent?=?new?Intent();??
intent.setAction("...");??
Context.sendOrderedBroadcast(intent,null);??
廣播接收者核心代碼：
[java]?view plaincopy
public?class?Receiver?extends?BroadcastReceiver{??
????public?void?onReceive(Context?context,?Intent?intent)?{??
????????Bundle?bundle?=?intent.getExtras();??
????????...??
????}??
}??
AndroidManifest.xml
[html]?view plaincopy
<application>???????????
????<receiver?android:name=".Receiver">???
????????<intent-filter?android:priority="1000">???
????????????<action?android:name="com.xiazdong"/>??
????????</intent-filter>??
????</receiver>??
</application>??????????
三、廣播實例
1.同步廣播實例
場景說明：
(1)廣播發(fā)送者：
[java]?view plaincopy
package?com.xiazdong.broadcastsender;??
??
import?android.app.Activity;??
import?android.content.Intent;??
import?android.os.Bundle;??
import?android.view.View;??
import?android.view.View.OnClickListener;??
import?android.widget.Button;??
import?android.widget.Toast;??
??
public?class?MainActivity?extends?Activity?{??
????private?Button?button;??
????private?OnClickListener?listener?=?new?OnClickListener(){??
????????@Override??
????????public?void?onClick(View?v)?{??
????????????Intent?intent?=?new?Intent();??
????????????intent.setAction("com.xiazdong");??
????????????intent.putExtra("name",?"xiazdong");??
????????????MainActivity.this.sendBroadcast(intent);??
????????????Toast.makeText(getApplicationContext(),?"發(fā)送廣播成功",?Toast.LENGTH_SHORT).show();??
????????}??
????};??
????@Override??
????public?void?onCreate(Bundle?savedInstanceState)?{??
????????super.onCreate(savedInstanceState);??
????????setContentView(R.layout.main);??
????????button?=?(Button)this.findViewById(R.id.button);??
????????button.setOnClickListener(listener);??
????}??
}??
(2)廣播接收者
[java]?view plaincopy
package?com.xiazdong.broadcastreceiver1;??
??
import?android.content.BroadcastReceiver;??
import?android.content.Context;??
import?android.content.Intent;??
import?android.util.Log;??
??
public?class?Receiver?extends?BroadcastReceiver?{??
??
????@Override??
????public?void?onReceive(Context?context,?Intent?intent)?{??
????????String?name?=?intent.getExtras().getString("name");??
????????Log.i("Recevier1",?"接收到:"+name);??
????}??
??
}??
AndroidManifest.xml
[java]?view plaincopy
<receiver?android:name=".Receiver">??
????????<intent-filter>??
?????????????<action?android:name="com.xiazdong"/>??
????????</intent-filter>??
</receiver>??
結(jié)果：
2.有序廣播實例
場景說明：
(1)廣播發(fā)送者
[java]?view plaincopy
package?com.xiazdong.broadcastsender;??
??
import?android.app.Activity;??
import?android.content.Intent;??
import?android.os.Bundle;??
import?android.view.View;??
import?android.view.View.OnClickListener;??
import?android.widget.Button;??
import?android.widget.Toast;??
??
public?class?MainActivity?extends?Activity?{??
????private?Button?button;??
????private?OnClickListener?listener?=?new?OnClickListener(){??
????????@Override??
????????public?void?onClick(View?v)?{??
????????????Intent?intent?=?new?Intent();??
????????????intent.setAction("com.xiazdong");??
????????????intent.putExtra("name",?"xiazdong");??
????????????MainActivity.this.sendOrderedBroadcast(intent,?null);???//有序廣播發(fā)送??
????????????Toast.makeText(getApplicationContext(),?"發(fā)送廣播成功",?Toast.LENGTH_SHORT).show();??
????????}??
????};??
????@Override??
????public?void?onCreate(Bundle?savedInstanceState)?{??
????????super.onCreate(savedInstanceState);??
????????setContentView(R.layout.main);??
????????button?=?(Button)this.findViewById(R.id.button);??
????????button.setOnClickListener(listener);??
????}??
}??
(2)廣播接收者
Receiver1
[java]?view plaincopy
package?com.xiazdong.broadcastreceiver1;??
??
import?android.content.BroadcastReceiver;??
import?android.content.Context;??
import?android.content.Intent;??
import?android.util.Log;??
??
public?class?Receiver?extends?BroadcastReceiver?{??
??
????@Override??
????public?void?onReceive(Context?context,?Intent?intent)?{??
????????String?name?=?intent.getExtras().getString("name");??
????????Log.i("Recevier1",?"接收到:"+name);??
????????abortBroadcast();???//Receiver1接收到廣播后中斷廣播??
????}??
??
}??
AndroidManifest.xml
[html]?view plaincopy
<receiver?android:name=".Receiver">??
??????<intent-filter?android:priority="1000">?<!--?設(shè)置最高優(yōu)先級?-->??
?????????<action?android:name="com.xiazdong"/>??
??????</intent-filter>??
?</receiver>??
轉(zhuǎn)載于:https://blog.51cto.com/lm910627/1659183
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