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0.Android 中的广播主要可以分为两种类型,标准广播和有序广播。标准广播(Normal broadcasts)是一种完全异步执行的广播,在广播发出之后,所有的 广播接收器几乎都会在同一时刻接收到这条广播消息，
有序广播(Ordered broadcasts)则是一种同步执行的广播,在广播发出之后,同一时刻 只会有一个广播接收器能够收到这条广播消息。
1.监听系统广播（电量/wifi/时区变化...）
如果需要监听系统广播，需要两步：
（1）重写BroadcastReceiver中的onReceive方法即可，实现自己的接收器；
public class NetworkChangeReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context,"network change",Toast.LENGTH_SHORT).show(); } }
（2）定义一个意图过滤器，过滤出广播
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); intentFilter = new IntentFilter(); intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE"); networkChangeReceiver = new NetworkChangeReceiver(); registerReceiver(networkChangeReceiver,intentFilter); }
（3）在AndroidMainifest.xml中注册
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.alex.learn.broadcasttest"> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
2.发送普通广播
（1）实现一个广播接收器MyBroadcastReceiver，定义在接收到广播时做什么事情
public class MyBroadcastReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context, "received in MyBroadcastReceiver", Toast.LENGTH_SHORT).show(); } }
（2）实现一个广播发送器，定义广播的发送
public class MainActivity extends AppCompatActivity { private IntentFilter intentFilter; private NetWorkChangeReceiver netWorkChangeReceiver; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button button = (Button) findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent("com.example.broadcasttest.MY_BROADCAST"); sendBroadcast(intent); } }); }
现在com.example.broadcasttest.MY_BROADCAST被绑定在意图中，因此需要通过在AndroidMainifest.xml中注册一个receiver即可
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.alex.learn.broadcasttest">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
...
<receiver android:name=".MyBroadcastReceiver">
<intent-filter>
<action android:name="com.example.broadcasttest.MY_BROADCAST"/>
</intent-filter>
</receiver>
</application>
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原文地址：http://www.cnblogs.com/alexkn/p/5479944.html
