Question

I have a service that performs background updates.

I want to give the user the the option to disable the updates when their battery percentage reaches a certain level.

From my research, I’m going to use a receiver in the onCreate method of my Service class, eg:

 public class MainService extends Service  
 {  
     @Override
     public void onCreate()
     {      
        this.registerReceiver(this.BatInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
     }

    private BroadcastReceiver BatInfoReceiver = new BroadcastReceiver(){  
         @Override  
         public void onReceive(Context arg0, Intent intent) {  
           int level = intent.getIntExtra("level", 0);  
    }  
  };
 }

I’m assuming that the best practice is to leave the service running, check the battery level in the service, and not perform the CPU-intensive code, based on the percentage?

I don’t actually need to stop the service itself and start it up again, based on the battery percentage?

UPDATE:

This seems to be a better solution, but not 100% sure. I registered a BroadcastReceiver in the AndroidManifest:

<receiver android:name="BatteryReceiver" /> 

Then created a BroadcastReceiver:

 public class BatteryReceiver extends BroadcastReceiver 
 {  
     @Override
     public void onReceive(final Context context, final Intent intent) 
     {      
         final int currentBatteryPercent = intent.getIntExtra("level", 0);
        final int disableBatteryPercent = Integer.parseInt(PreferenceManager.getDefaultSharedPreferences(context).getString("batteryPercent", 0);

        //AlarmReceiver is the service that performs the background updates
         final ComponentName component = new ComponentName(context, AlarmReceiver.class);

         if (currentBatteryPercent < disableBatteryPercent)
         {
             context.getPackageManager().setComponentEnabledSetting(component, PackageManager.COMPONENT_ENABLED_STATE_DISABLED , PackageManager.DONT_KILL_APP);
         }
         else
         {
             context.getPackageManager().setComponentEnabledSetting(component, PackageManager.COMPONENT_ENABLED_STATE_ENABLED , PackageManager.DONT_KILL_APP);
         }
      }
 }

Answer 1

That’s right. What you will typically do is schedule some broadcast intent for an update (perhaps through an AlarmManager). When you get the notification that there is a low battery, you will stow this away in your service, and then before doing an update, check to ensure that the battery isn’t too low. here is a good tutorial of watching the battery level. You shouldn’t do much when handling this intent, just stick the battery level somewhere and (before doing an update) make sure it’s appropriately “full.”

Your update is a really bad way to stop an app. In general, asking the package manager to stop your component is much more of a hack than a solution. Instead, you should move some code into the component that actually does the updating, and store / update the information for the battery info there. Before you do an update, you check the battery level and don’t proceed unless it’s at a level where you feel comfortable updating the app. Using a broadcast receiver is fine, but you need to store the level somewhere (perhaps a sharedprefs). Instead, this is why putting the receiver within the service where you do the updating is probably best.