Question

我需要在一定的时间间隔之后将用户的位置发送到Web服务器，目前每两分钟发送一次。除非应用正在运行，否则它工作正常。当应用程序处于后台位置时，停止更新，一次又一次地发送相同的位置。我有点困惑。如果有人建议替代我的方法，那将会很棒。我点击按钮开始发送位置并且不会停止，除非并且直到用户点击按钮停止。以下是我的代码。我想将用户的当前位置发送到Web服务器，无论应用程序是否正在运行。任何帮助表示赞赏。问题是在一定间隔后没有发送位置，问题是位置停止更新如果我杀死应用程序坐标保持不变。如果应用程序在前台运行，那么即使设备轻微倾斜也会使坐标发生变化。我之前使用firebaseJobDispatcher来调用此服务。问题不在于调用服务。问题是位置停止更新并且每次我调用服务时都保持相同，如果我已经杀死了应用程序。

我使用闹钟管理器每2分钟拨打一次此服务。

public class GPSTracker_DUP extends Service implements LocationListener {

    private  Context mContext=null;
    RetrofitAPI retrofitAPI;

    // flag for GPS status
    boolean isGPSEnabled = false;

    // flag for network status
    boolean isNetworkEnabled = false;

    // flag for GPS status
    boolean canGetLocation = false;

    SaveData objSaveData;
    Location location; // location
    double latitude; // latitude
    double longitude; // longitude
    private String provider;
    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    public GPSTracker_DUP(Context context) {
        this.mContext = context;
        //getLocation();
    }

    public GPSTracker_DUP(){}



    public Location getLocation() {
        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(LOCATION_SERVICE);


            Criteria criteria = new Criteria();
            provider = locationManager.getBestProvider(criteria, false);

            if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                // TODO: Consider calling
                //    ActivityCompat#requestPermissions
                // here to request the missing permissions, and then overriding
                //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                //                                          int[] grantResults)
                // to handle the case where the user grants the permission. See the documentation
                // for ActivityCompat#requestPermissions for more details.
                return null;
            }

            // getting GPS status
            isGPSEnabled = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);
            if(!isGPSEnabled)
            {
                showSettingsAlert();

            }
            else
            {

                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,1000*60*2,0,this);
                location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

                if (location != null) {
                    Log.e("Provider ",  provider + " has been selected."+location.getLatitude()+"==="+location.getLongitude());

                    saveLocation(location.getLatitude(),location.getLongitude());

                    //onLocationChanged(location);
                }
            }


            // getting network status
//            isNetworkEnabled = locationManager
//                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);


        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }


    public static boolean isConnected(Context context){
        NetworkInfo info = getNetworkInfo(context);
        return (info != null && info.isConnected());
    }

    public static NetworkInfo getNetworkInfo(Context context){
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm.getActiveNetworkInfo();
    }
    /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in your app
     * */
    public void stopUsingGPS(){
        if(locationManager != null){
            locationManager.removeUpdates(GPSTracker_DUP.this);
        }
    }

    /**
     * Function to get latitude
     * */
    public double getLatitude(){
        if(location != null){
            latitude = location.getLatitude();
        }

        // return latitude
        return latitude;
    }

    /**
     * Function to get longitude
     * */
    public double getLongitude(){
        if(location != null){
            longitude = location.getLongitude();
        }

        // return longitude
        return longitude;
    }

    /**
     * Function to check GPS/wifi enabled
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }


    /**
     * Function to show settings alert dialog
     * On pressing Settings button will lauch Settings Options
     * */
    public void showSettingsAlert(){
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        // Setting Dialog Title
        alertDialog.setTitle("GPS is settings");

        // Setting Dialog Message
        alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing Settings button
        alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });

        // on pressing cancel button
        alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });

        // Showing Alert Message
        alertDialog.show();
    }


    @Override
    public void onLocationChanged(Location location) {
        latitude = location.getLatitude();
        longitude = location.getLongitude();
        Log.e("onlocation","changed");


    }
    public void saveLocation(Double latitude,Double longitude){
        objSaveData = new SaveData(mContext);

            Log.e("Saving Coordinates", latitude + " " + longitude);
            AudioDbHelper audioDbHelper= new AudioDbHelper(mContext);
            UserCoordinates userCoordinates = new UserCoordinates();
            userCoordinates.setLatitude(String.valueOf(latitude));
            userCoordinates.setLongitude(String.valueOf(longitude));
            userCoordinates.setUploaded("no");
            SaveData objSaveData = new SaveData(mContext);
            userCoordinates.setUserEmail(objSaveData.getString("LoginId"));
            String time = new SimpleDateFormat("hh:mm: aa").format(Calendar.getInstance().getTime());
            userCoordinates.setLocationTime(time);
            audioDbHelper.addCoordinates(userCoordinates);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        stopUsingGPS();
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

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

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

Answer 1

由于您需要在一段时间后发送位置，因此最好使用在一段时间后启动服务的Job Scheduler，获取位置并进行API调用。

最好的是Job Scheduler，这是Google推荐的，但Android版本限制了它的使用，最好使用Evernote Android Job。根据Android版本，使用JobScheduler，GcmNetworkManager或AlarmManager。

您不必担心服务被杀，因为现在操作系统有责任启动服务

还要提取位置，使用Google Play位置来获取位置。它的作用是从您的设备中获取Google Play服务的位置，该位置会不时更新。

看一下我在我的一个项目中用来从正在运行的服务中获取位置的Util类。它在Kotlin并使用Dagger2，但你会得到这个想法。它有一个回调界面，可以通过Google Play位置服务

回复当前位置和地址

ServiceLocationUtil.kt

Answer 2

默认情况下，您需要为此Start_Sticky创建START_STICKY_COMPATIBILITY服务。覆盖onStartCommand()。

 @Override
public int onStartCommand(Intent intent, int flags, int startId){
    // Do your Stuff
    return START_STICKY;
}

然而由于背景限制，这在最新版本的android中不起作用。因此，您可能希望结帐Background Location Limits和Android 8.0 Behavior Changes。

如果您需要在一段时间后发送位置，建议您使用JobShedular。有一些可用，例如Evernote android-job，Firebase JobDispatcher。

另请阅读Intelligent Job-Scheduling。

Answer 3

您应将WorkManager或FirebaseJobDispatcher用于后台进程。但是Android Q不支持FirebaseJobDispatcher。

这是我使用WorkManager在后台获取位置的解决方案

在活动或片段中定义

   private fun startTaskWithWorkManager() {
    val constraints: Constraints = Constraints.Builder()
        .setRequiredNetworkType(NetworkType.CONNECTED)
        .build()
    val locationWorker =
        PeriodicWorkRequest.Builder(LocationWorker::class.java, MIN_PERIODIC_INTERVAL_MILLIS, TimeUnit.MILLISECONDS)
            .setConstraints(constraints)
            .addTag(LOCATION_WORKER_TAG)
            .setInputData(createInputData())
            .build()
    WorkManager.getInstance()
        .enqueueUniquePeriodicWork(LOCATION_WORKER_TAG, ExistingPeriodicWorkPolicy.KEEP, locationWorker)
}

之后，您应该创建一个将从ListenableWorker扩展的类。就我而言，我必须使用ListenableWorker而不是Worker。您可以找到here和here的不同之处。

class LocationWorker(context: Context, private val workerParams: WorkerParameters) :
ListenableWorker(context, workerParams) {

lateinit var mFuture: SettableFuture<ListenableWorker.Result>
private var fusedLocationProviderClient = FusedLocationProviderClient(context)

@SuppressLint("RestrictedApi", "MissingPermission")
override fun startWork(): ListenableFuture<Result> {
    val uniqueId = workerParams.inputData.getString(UNIQUE_ID_KEY)
    mFuture = SettableFuture.create()
    Timber.d("mFutureStart")
    fusedLocationProviderClient.lastLocation.addOnSuccessListener { location ->
        Timber.d("location == $location")
        if (location != null) {
             mFuture.set(Result.success())
        } else mFuture.set(Result.failure())
      }
    return mFuture
  }
}

就这样:) 像魅力一样工作

应用程序被杀时，GPS位置无法获取更新

3 个答案: