应用未打开或关闭时的后台服务

编程问答 2022-06-06

问题描述

我有一个定位服务，可以在Firestore中添加/更新数据。打开应用程序后，它可以正常工作，但是如果我强制关闭应用程序或切换到另一个应用程序，则该服务将不再起作用。我在Realme 3专业版设备上对此进行了测试。

  1. 即使在应用程序管理器中关闭了应用程序，也要运行服务。

服务等级 

public class LocationService extends Service {
private static final String TAG = "SERVICE";
private LocationManager mLocationManager = null;
private static final int LOCATION_INTERVAL = 0;
private static final float LOCATION_disTANCE = 0;

private class LocationListener implements android.location.LocationListener {
    Location mLastLocation;

    public LocationListener(String provider) {
        Log.e(TAG,"LocationListener " + provider);
        mLastLocation = new Location(provider);
    }


    @Override
    public void onLocationChanged(Location location) {

        mLastLocation.set(location);
    }

    @Override
    public void onProviderdisabled(String provider) {
        Log.e(TAG,"onProviderdisabled: " + provider);
    }

    @Override
    public void onProviderEnabled(String provider) {
        Log.e(TAG,"onProviderEnabled: " + provider);
    }

    @Override
    public void onStatusChanged(String provider,int status,Bundle extras) {
        Log.e(TAG,"onStatusChanged: " + provider);
    }
}

LocationListener[] mLocationListeners = new LocationListener[]{
        new LocationListener(LocationManager.GPS_PROVIDER),new LocationListener(LocationManager.NETWORK_PROVIDER)
};

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

@Override
public int onStartCommand(Intent intent,int flags,int startId) {
    Log.e(TAG,"onStartCommand");
    super.onStartCommand(intent,flags,startId);
    LocationInitialize();
    return START_STICKY;
}

@Override
public void onCreate() {
    Log.e(TAG,"onCreate");

}

public void LocationInitialize(){
    initializeLocationManager();
    try {
        mLocationManager.requestLocationUpdates(
                LocationManager.NETWORK_PROVIDER,LOCATION_INTERVAL,LOCATION_disTANCE,mLocationListeners[1]);
    } catch (java.lang.SecurityException ex) {
        Log.i(TAG,"fail to request location update,ignore",ex);
    } catch (IllegalArgumentException ex) {
        Log.d(TAG,"network provider does not exist," + ex.getMessage());
    }
    try {
        mLocationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER,mLocationListeners[0]);
    } catch (java.lang.SecurityException ex) {
        Log.i(TAG,"gps provider does not exist " + ex.getMessage());
    }
}

@Override
public void onDestroy() {
    Log.e(TAG,"onDestroy");
    super.onDestroy();

    Intent broadcastIntent = new Intent();
    broadcastIntent.setAction("restartservice");
    broadcastIntent.setClass(this,RestartService.class);
    this.sendbroadcast(broadcastIntent);
}

private void initializeLocationManager() {
    Log.e(TAG,"initializeLocationManager");
    if (mLocationManager == null) {
        mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
    }
}

@Override
public void onTaskRemoved( Intent rootIntent ) {
    Intent broadcastIntent = new Intent();
    broadcastIntent.setAction("restartservice");
    broadcastIntent.setClass(this,RestartService.class);
    this.sendbroadcast(broadcastIntent);
}
}

广播接收 

public class RestartService extends broadcastReceiver {

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

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        context.startForegroundService(new Intent(context,LocationService.class));
    } else {
        context.startService(new Intent(context,LocationService.class));
    }
}
}

Android清单 

<receiver
        android:name=".service.RestartService"
        android:enabled="true"
        android:stopWithTask="false"
        android:exported="true">
        <intent-filter>
            <action android:name="restartservice" />
        </intent-filter>
    </receiver>

    <service
        android:name=".service.LocationService"
        android:enabled="true"
        android:exported="true" />

解决方法

根据Google Developer最近的政策，您不应该使用 基于清单的广播接收器，尽管它不能在26以上运行 SDK

https://developer.android.com/guide/components/broadcasts#changes-system-broadcasts

因此无需使用广播接收器即可重新启动服务。

使用此代码重新启动服务

更新的服务等级

public class LocationService extends Service {
private static final String TAG = "SERVICE";
private LocationManager mLocationManager = null;
private static final int LOCATION_INTERVAL = 0;
private static final float LOCATION_DISTANCE = 0;

private class LocationListener implements android.location.LocationListener {
    Location mLastLocation;

    public LocationListener(String provider) {
        Log.e(TAG,"LocationListener " + provider);
        mLastLocation = new Location(provider);
    }


    @Override
    public void onLocationChanged(Location location) {

        mLastLocation.set(location);
    }

    @Override
    public void onProviderDisabled(String provider) {
        Log.e(TAG,"onProviderDisabled: " + provider);
    }

    @Override
    public void onProviderEnabled(String provider) {
        Log.e(TAG,"onProviderEnabled: " + provider);
    }

    @Override
    public void onStatusChanged(String provider,int status,Bundle extras) {
        Log.e(TAG,"onStatusChanged: " + provider);
    }
}

LocationListener[] mLocationListeners = new LocationListener[]{
        new LocationListener(LocationManager.GPS_PROVIDER),new LocationListener(LocationManager.NETWORK_PROVIDER)
};

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

@Override
public int onStartCommand(Intent intent,int flags,int startId) {
    Log.e(TAG,"onStartCommand");
    super.onStartCommand(intent,flags,startId);
    LocationInitialize();
    return START_STICKY;
}

  @Override
    public void onCreate() {
        super.onCreate();      
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            startMyOwnForeground();
        } else {
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this,"1");
            Notification notification = notificationBuilder.setOngoing(true)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("My service.")
                    .setPriority(NotificationManager.IMPORTANCE_MIN)
                    .setCategory(Notification.CATEGORY_SERVICE)
                    .build();
            startForeground(1,notification);
        }
    }

  @RequiresApi(api = Build.VERSION_CODES.O)
    private void startMyOwnForeground() {
        String channelName = "My service";
        NotificationChannel chan = new NotificationChannel("2",channelName,NotificationManager.IMPORTANCE_NONE);
        chan.setLightColor(Color.BLUE);
        chan.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
        NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        assert manager != null;
        manager.createNotificationChannel(chan);

        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this,"2");
        Notification notification = notificationBuilder.setOngoing(true)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("My service")
                .setPriority(NotificationManager.IMPORTANCE_MIN)
                .setCategory(Notification.CATEGORY_SERVICE)
                .build();
        startForeground(2,notification);
    }

public void LocationInitialize(){
    initializeLocationManager();
    try {
        mLocationManager.requestLocationUpdates(
                LocationManager.NETWORK_PROVIDER,LOCATION_INTERVAL,LOCATION_DISTANCE,mLocationListeners[1]);
    } catch (java.lang.SecurityException ex) {
        Log.i(TAG,"fail to request location update,ignore",ex);
    } catch (IllegalArgumentException ex) {
        Log.d(TAG,"network provider does not exist," + ex.getMessage());
    }
    try {
        mLocationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER,mLocationListeners[0]);
    } catch (java.lang.SecurityException ex) {
        Log.i(TAG,"gps provider does not exist " + ex.getMessage());
    }
}

@Override
public void onDestroy() {
    Log.e(TAG,"onDestroy");
    super.onDestroy();
    // no need to do anything here
    //Intent broadcastIntent = new Intent();
    //broadcastIntent.setAction("restartservice");
    //broadcastIntent.setClass(this,RestartService.class);
    //this.sendBroadcast(broadcastIntent);
}

private void initializeLocationManager() {
    Log.e(TAG,"initializeLocationManager");
    if (mLocationManager == null) {
        mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
    }
}

    @Override
    public void onTaskRemoved(Intent rootIntent) {
        Intent restartServiceIntent = new Intent(getApplicationContext(),this.getClass());
        restartServiceIntent.setPackage(getPackageName());

        PendingIntent restartServicePendingIntent = PendingIntent.getService(getApplicationContext(),1,restartServiceIntent,PendingIntent.FLAG_ONE_SHOT);
        AlarmManager alarmService = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
        alarmService.set(
                AlarmManager.ELAPSED_REALTIME,SystemClock.elapsedRealtime() + 1000,restartServicePendingIntent);

        super.onTaskRemoved(rootIntent);
    }
}
androidandroidandroid-gpsandroid-servicelocationmanager