在Java代码中指定IntentFilter,然后想监听什么广播就添加对应的Action。动态注册的广播,一定要调用unregisterReceiver()方法取消注册。
下面用动态注册监听网络变化
在AndroidManifest.xml中添加权限:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
Activity的Java代码:
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);
//动态接受网络变化的广播接收器
intentFilter = new IntentFilter();
intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
networkChangeReceiver = new NetworkChangeReceiver();
registerReceiver(networkChangeReceiver, intentFilter);
}
@Override
protected void onDestroy() {
super.onDestroy();
//取消动态网络变化广播接收器的注册
unregisterReceiver(networkChangeReceiver);
}
//自定义接受网络变化的广播接收器
class NetworkChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
ConnectivityManager connectionManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectionManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isAvailable()) {
Toast.makeText(context, "network is available", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "network is unavailable", Toast.LENGTH_SHORT).show();
}
}
}
}
动态注册需要程序启动之后才能接收广播,静态广播就弥补了这个短板。在AndroidManifest中指定IntentReceiver就可以在程序未启动的情况下接收到广播
下面用静态注册接受开机广播
新建一个广播接收器
public class MyBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "received in MyBroadcastReceiver", Toast.LENGTH_SHORT).show();
}
}
在AndroidManifest.xml中添加权限、注册广播接收器和添加Action
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcasttest">
<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">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
intent-filter>
activity>
<receiver
android:name=".BootCompleteReceiver"
android:enabled="true"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
intent-filter>
receiver>
application>
manifest>
接收器的Java代码:
public class MyBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "received in MyBroadcastReceiver", Toast.LENGTH_SHORT).show();
}
}
接收器的注册代码:
<receiver
android:name=".MyBroadcastReceiver"
android:enabled="true"
android:exported="true">
<intent-filter>
<action android:name="com.example.broadcasttest.MY_BROADCAST" />
intent-filter>
receiver>
Activity的Java代码
public class MainActivity extends AppCompatActivity {
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//发送自定义广播
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);
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
//取消动态网络变化广播接收器的注册
unregisterReceiver(networkChangeReceiver);
}
}
发送有序广播的方法:
sendOrderedBroadcast(intent, null);
设置广播接收器的先后顺序,在AndroidManifest.xml中receiver的intent-filter的priority属性,优先级可选值:-1000~1000
android:priority="100"
主要是用LocalBroadcastManager来对广播进行管理,提供了发送广播和注册广播接收器的方法如下:
注意事项:
Java代码:
public class MainActivity extends AppCompatActivity {
private IntentFilter intentFilter;
private LocalReceiver localReceiver;
private LocalBroadcastManager localBroadcastManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//得到本地广播管理器的实例
localBroadcastManager = LocalBroadcastManager.getInstance(this);
//动态注册本地广播接收器
intentFilter = new IntentFilter();
intentFilter.addAction("com.example.broadcasttest.LOCAL_BROADCAST");
localReceiver = new LocalReceiver();
localBroadcastManager.registerReceiver(localReceiver, intentFilter);
//发送本地广播
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.LOCAL_BROADCAST");
localBroadcastManager.sendBroadcast(intent);
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
//取消动态网络变化广播接收器的注册
localBroadcastManager.unregisterReceiver(localReceiver);
}
class LocalReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "received local broadcast", Toast.LENGTH_SHORT).show();
}
}
}