Android电池广播

Question

我正在尝试制作电池报警应用程序。我正在阅读Android文档，发现我们不需要注册BroadcastReceiver。我们可以做这样的事情这 -

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED); 
Intent batteryStatus = context.registerReceiver(null, ifilter); 

我的问题是 -

• 系统是否广播意图（含电池状态）每次 电池电量的变化？
• 我必须每次查询电池电量吗？
• 此外，如何在电池电量达到 特定级别（由用户设置）时播放闹钟。

Answer 1

这里是一个全样本取电池级

private float getBatteryLevel() { 
    Intent batteryStatus = registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 
    int batteryLevel = -1; 
    int batteryScale = 1; 
    if (batteryStatus != null) { 
     batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, batteryLevel); 
     batteryScale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, batteryScale); 
    } 
    return batteryLevel/(float) batteryScale * 100; 
    } 

回答你的问题：

1 - 是的，你可以通过getExtra得到更多的信息和确定键，BatteryManager有很多的密钥从意图中提取信息。

2-不，您只需根据活动或片段生命周期注册接收者并注销它，通常在onCreate()/onCreateView()中注册并取消注册onDestry()/onDestroyView()。

3-您可以创建一个具有简单通知界面的绑定服务。注册您reciever就可以了，从以前的样品，你可以做这样的事情：

if (getBatteryLevel < 10) { 
//show notification or do whatever you want. 
} 

Answer 2

首先在清单文件中添加意图过滤器：

<receiver android:name=".BatteryLevelReceiver"> 
    <intent-filter> 
    <action android:name="android.intent.action.BATTERY_LOW"/> 
    <action android:name="android.intent.action.BATTERY_OKAY"/> 
    <action android:name="android.intent.action.ACTION_POWER_CONNECTED"/> 
    <action android:name="android.intent.action.ACTION_POWER_DISCONNECTED"/> 
    </intent-filter> 
</receiver> 

在项目中添加新的类后：

public class PowerConnectionReceiver extends BroadcastReceiver { 
    @Override 
    public void onReceive(Context context, Intent intent) { 
     int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1); 
     boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING || 
          status == BatteryManager.BATTERY_STATUS_FULL; 

     int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1); 
     boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB; 
     boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC; 
    } 
} 

对于获取电池级：

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED); 
Intent batteryStatus = context.registerReceiver(null, ifilter); 

int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1); 
int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1); 

float batteryPct = level/(float)scale; 

更多信息这个链接：developer.android

Answer 3

创建接收器获取信息..这是更好的方法。

public class PowerConnectionReceiver extends BroadcastReceiver { 
    @Override 
    public void onReceive(Context context, Intent intent) { 
     int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1); 
     boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING || 
          status == BatteryManager.BATTERY_STATUS_FULL; 

     int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1); 
     boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB; 
     boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC; 
    } 
} 

在清单中添加

<receiver android:name=".PowerConnectionReceiver"> 
    <intent-filter> 
    <action android:name="android.intent.action.ACTION_POWER_CONNECTED"/> 
    <action android:name="android.intent.action.ACTION_POWER_DISCONNECTED"/> 
    <action android:name="android.intent.action.BATTERY_LOW"/> 
    <action android:name="android.intent.action.BATTERY_OKAY"/> 
    </intent-filter> 
</receiver> 

更多信息请访问LINK

Answer 4

Q1. Yes, system provide every time . 
Example :  
     private class BatteryBroadcastReceiver extends BroadcastReceiver { 
      private final static String BATTERY_LEVEL = "level"; 
      @Override 
      public void onReceive(Context context, Intent intent) { 
       int level = intent.getIntExtra(BATTERY_LEVEL, 0); 
       mBatteryLevelText.setText(getString(R.string.battery_level) + " " + level); 
       mBatteryLevelProgress.setProgress(level); 
      } 
     } 


//Register our BroadcastReceiver in application 

    BatteryBroadcastReceiver mReceiver = new BatteryBroadcastReceiver(); 
    registerReceiver(mReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 


//Update your progress bar get 

    public class MainActivity extends Activity { 
     private TextView mBatteryLevelText; 
     private ProgressBar mBatteryLevelProgress; 
     private BroadcastReceiver mReceiver; 
     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main); 
      mBatteryLevelText = (TextView) findViewById(R.id.textView); 
      mBatteryLevelProgress = (ProgressBar) findViewById(R.id.progressBar); 
      mReceiver = new BatteryBroadcastReceiver(); 
     } 
     @Override 
     protected void onStart() { 
      registerReceiver(mReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 
      super.onStart(); 
     } 
     @Override 
     protected void onStop() { 
      unregisterReceiver(mReceiver); 
      super.onStop(); 
     } 
     private class BatteryBroadcastReceiver extends BroadcastReceiver { 
      @Override 
      public void onReceive(Context context, Intent intent) { 
       int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0); 
       mBatteryLevelText.setText(getString(R.string.battery_level) + " " + level); 
       mBatteryLevelProgress.setProgress(level); 
if(level<10){ 
// play Battery alarm. 

      } 
     } 
    }