How to always run a service in the background?_问答_开发者

I am in the process of creating an app that is similar to the built-in SMS app.

What I need:

a service that is always running in the background
every 5 min. the service checks the current location of the device and calls a web service
if certain criteria are met, the service should generate a notification (just like the SMS app)
when the notification is clicked, the user is taken to the app (just like the SMS app)
when the app is installed the service should be started
when the device is rebooted, the service should be started

What I have tried:

- running a regular service which worked just fine until Android kills the service

- using the AlarmManager to make the 5 min. interval call t开发者_JAVA技巧o a service. But I was not able to make this work.

a service that is always running in the background

This is not possible in any real sense of the term, as you have discovered. It is also bad design.

every 5 min. the service checks the current location of the device and calls a web service

Use AlarmManager.

using the AlarmManager the make the 5 min. interval call to a service. But I was not able to make this work.

Here is a sample project showing how to use one, along with the use of WakefulIntentService so you stay awake while trying to do the whole Web service thing.

If you have continued problems with it, open up a new question about the specific things you are encountering with AlarmManager that are giving you grief.

One of my apps does something very similar. To wake the service after a given period I recommend postDelayed()

Have a handler field:

private final Handler handler = new Handler();

and a refresher Runnable

private final Runnable refresher = new Runnable() {
  public void run() {
    // some action
  }
};

You can fire your Notifications in the runnable.

On service construction, and after each execution start it like so:

handler.postDelayed(refresher, /* some delay in ms*/);

In onDestroy() remove the post

handler.removeCallbacks(refresher);

To start the service at boot time you need an auto starter. This goes in your manifest

<receiver android:name="com.example.ServiceAutoStarter">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
  </receiver>

and the ServiceAutoStarter looks like this:

public class ServiceAutoStarter extends BroadcastReceiver {
  @Override
  public void onReceive(Context context, Intent intent) {
    context.startService(new Intent(context, UpdateService.class));
  }
}

Stopping the OS from killing the service is tricky. Also your application can have a RuntimeException and crash, or your logic can stall.

In my case it seemed to help to always refresh the service on screen on with a BroadcastReceiver. So if the chain of updates gets stalled it will be resurrected as the user uses their phone.

In the service:

private BroadcastReceiver screenOnReceiver;

In your service onCreate()

screenOnReceiver = new BroadcastReceiver() {

  @Override
  public void onReceive(Context context, Intent intent) {
    // Some action
  }
};

registerReceiver(screenOnReceiver, new IntentFilter(Intent.ACTION_SCREEN_ON));

Then unregister your service on onDestroy() with

unregisterReceiver(screenOnReceiver);

You can do this by some simple implementation:

public class LocationTrace extends Service implements LocationListener{

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
    private static final int TWO_MINUTES = 100 * 10;

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 10; // 30 seconds

    private Context context;

    double latitude;
    double longitude;

    Location location = null;
    boolean isGPSEnabled = false;
    boolean isNetworkEnabled = false;
    protected LocationManager locationManager;


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        this.context = this;
        get_current_location();
//      Toast.makeText(context, "Lat"+latitude+"long"+longitude,Toast.LENGTH_SHORT).show();
        return START_STICKY;
    }


    @Override
    public void onLocationChanged(Location location) {
        if((location != null) && (location.getLatitude() != 0) && (location.getLongitude() != 0)){

            latitude = location.getLatitude();
            longitude = location.getLongitude();

            if (!Utils.getuserid(context).equalsIgnoreCase("")) {
                Double[] arr = { location.getLatitude(), location.getLongitude() };

               // DO ASYNCTASK
            }
        }

    }


    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }

    /*
    *  Get Current Location
    */
    public Location get_current_location(){

        locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

        isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

        isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if(!isGPSEnabled && !isNetworkEnabled){



        }else{
            if (isGPSEnabled) {

                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

                    if (locationManager != null) {
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
        //                  Toast.makeText(context, "Latgps"+latitude+"long"+longitude,Toast.LENGTH_SHORT).show();
                        }
                    }
                }
            }
            if (isNetworkEnabled) {

                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

                if (locationManager != null) {

                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
        //              Toast.makeText(context, "Latgps1"+latitude+"long"+longitude,Toast.LENGTH_SHORT).show();
                    }
                }
            }
        }

        return location;
    }


    public double getLatitude() {
        if(location != null){
            latitude = location.getLatitude();
        }
        return latitude;
    }

    public double getLongitude() {
         if(location != null){
             longitude = location.getLongitude();
         }

        return longitude;
    }


    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onDestroy() {
        if(locationManager != null){
            locationManager.removeUpdates(this);
        }
        super.onDestroy();
    }

}

You can start service by this :

/*--Start Service--*/
startService(new Intent(Splash.this, LocationTrace.class));

In manifest:

 <service android:name=".LocationTrace">
            <intent-filter android:priority="1000">
                <action android:name="android.location.PROVIDERS_CHANGED"/>
                <category android:name="android.intent.category.DEFAULT"/>
            </intent-filter>
  </service>

by these three steps, you can wake every 5 minutes most of the Android devices :

1. set your alternative AlarmManager for diffrent APIs :

AlarmManager am = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(getApplicationContext(), OwnReceiver.class);
PendingIntent pi = PendingIntent.getBroadcast(getApplicationContext(), 0, i, 0);

if (Build.VERSION.SDK_INT >= 23) {
am.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
}
else if (Build.VERSION.SDK_INT >= 19) {
am.setExact(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
} else {
am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
}

2. build your own static BroadcastReceiver :

public static class OwnReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

       //do all of your jobs here

        AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent i = new Intent(context, OwnReceiver.class);
        PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);

        if (Build.VERSION.SDK_INT >= 23) {
            am.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
        }
        else if (Build.VERSION.SDK_INT >= 19) {
            am.setExact(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
        } else {
            am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);
        }
    }
}

3. add <receiver> to AndroidManifest.xml :

<receiver android:name=".OwnReceiver"  />

According to me when you want your service to run always means that it shouldn't get stopped when the app is killed, because if your app is running or is in the background anyways your service will be running. When you kill the app while a service is running the onTaskRemoved function is triggered.

@Override
        public void onTaskRemoved(Intent rootIntent) {
            Log.d(TAG, "onTaskRemoved: removed");
            Calendar calendar = Calendar.getInstance();
            calendar.setTimeInMillis(System.currentTimeMillis() + 10000);
((AlarmManager) getSystemService(Context.ALARM_SERVICE)).setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), PendingIntent.getService(getApplicationContext(), 0, new Intent(getApplicationContext(), RegisterReceiverService.class), 0));
            super.onTaskRemoved(rootIntent);
        }

So basically once you kill the app the service will be started after 10 seconds. Note: In case you want to use