在清单文件中声明广播接收器
<pre name="code" class="java"><?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test_sample"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.test_sample.BatteryInfoActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name="com.example.test_sample.BatteryReceiver">
<intent-filter>
<action android:name="android.intent.action.BATTERY_LOW"/>
</intent-filter>
</receiver>
</application>
</manifest>
BatteryReceiver的实现
public class BatteryReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String action=intent.getAction();
if(Intent.ACTION_BATTERY_LOW.equals(action)){
//执行方法
}
}
}
当应用不在运行或者在后台运行时,我们想禁用一些显示信息,因此只有当应用在前台运行时才可以启用广播接收器:
(1)广播接收器默认是禁用的;
(2)广播接收器必须在onResume()中启用,在onPause()被禁用。
在manifest文件中禁用广播接收器:
........
<receiver android:name=".BatteryReceiver" android:enabled="false">
..........
注:<application>元素有其自己的enabled属性。广播接收器会在<application>属性和<receiver>属性设置为true时被启用,在其中之一设置为false时禁用。
在代码中禁用广播接收器;
private void enableBatteryReceiver(boolean enabled){
PackageManager pm=getPackageManager();
ComponentName receiverName=new ComponentName(this, BroadcastReceiver.class);
int newState;
if(enabled){
newState=PackageManager.COMPONENT_ENABLED_STATE_ENABLED;
}else{
newState=PackageManager.COMPONENT_ENABLED_STATE_DISABLED;
}
pm.setComponentEnabledSetting(receiverName, newState, PackageManager.DONT_KILL_APP);
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
if(mBroadcast==null){
createBatteryReceiver();
}
registerReceiver(mBroadcast, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
enableBatteryReceiver(true);//电池接收器现在开启
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
//如果应用没有在前台运行,注销接收器以节省功耗
unregisterReceiver(mBroadcast);
enableBatteryReceiver(false);//电池接收器现在被禁用
}