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After enable gps from an app prompt how to refresh and get the current location?

由 别说谁变了你拦得住时间么 提交于 2019-12-22 10:46:21

问题


I am currently developing an Android app which prompts the user to enable GPS if it's not on and I have used Alert Dialog for this purpose. After I enable the GPS from settings and come back to my app by pressing back button, the toast message display 0.00,0.00. Although If I have my GPS on before running the app, the app properly displays my location. I want to know to which method to use for this refresh user location after enabling GPS purpose. Any relevant article would really help.

This is my gps class

          public class GpsTracker extends Service implements LocationListener {

private final Context mContext;

// flag for GPS status
boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
boolean canGetLocation = false;

Location location; // location
double latitude; // latitude
double longitude; // longitude

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

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

        // getting GPS status
        isGPSEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

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

        if (!isGPSEnabled && !isNetworkEnabled) {
            // no network provider is enabled
        } else {
            if (ActivityCompat.checkSelfPermission(mContext, 
             Manifest.permission.ACCESS_FINE_LOCATION) != 
                PackageManager.PERMISSION_GRANTED
                    && ActivityCompat.checkSelfPermission(mContext, 
                       Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                return null;
            }
            this.canGetLocation = true;
            // First get location from Network Provider
            if (isNetworkEnabled) {

              /*  locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);*/
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                            && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                        return null;
                    }
                  /*  locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);*/
                    Log.d("GPS Enabled", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

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

    return location;
}

/**
 * Stop using GPS listener
 * Calling this function will stop using GPS in your app
 * */
public void stopUsingGPS(){

    if(locationManager != null){
        if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

            return ;
        }
        locationManager.removeUpdates(GpsTracker.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) {
}

@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;
}

}

回答1:


Try this I am also facing the problem.

  • You have to reload your activity

  • After that, you can get location

  • take boolean in gps tracker class
  • make sure alert is in try catch to avoid crash if you want to enable or disable Gps. 
public class GpsTracker extends Service implements LocationListener {

private final Context mContext;

 public static boolean isFromSetting=false;
// flag for GPS status
boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
 boolean canGetLocation = false;

 Location location; // location
 double latitude; // latitude
 double longitude; // longitude

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

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

    // getting GPS status
    isGPSEnabled = locationManager
            .isProviderEnabled(LocationManager.GPS_PROVIDER);

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

    if (!isGPSEnabled && !isNetworkEnabled) {
        // no network provider is enabled
    } else {
        if (ActivityCompat.checkSelfPermission(mContext, 
    Manifest.permission.ACCESS_FINE_LOCATION) != 
      PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(mContext, 
  Manifest.permission.ACCESS_COARSE_LOCATION) != 
   PackageManager.PERMISSION_GRANTED) {

            return null;
        }
        this.canGetLocation = true;
        // First get location from Network Provider
        if (isNetworkEnabled) {

          /*  locationManager.requestLocationUpdates(
                    LocationManager.NETWORK_PROVIDER,
                    MIN_TIME_BW_UPDATES,
                    MIN_DISTANCE_CHANGE_FOR_UPDATES, this);*/
            Log.d("Network", "Network");
            if (locationManager != null) {
                location = locationManager
                        .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                if (location != null) {
                    latitude = location.getLatitude();
                    longitude = location.getLongitude();
                }
            }
        }
        // if GPS Enabled get lat/long using GPS Services
        if (isGPSEnabled) {
            if (location == null) {
                if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                        && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                    return null;
                }
              /*  locationManager.requestLocationUpdates(
                        LocationManager.GPS_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);*/
                Log.d("GPS Enabled", "GPS Enabled");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
        }
    }

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

return location;
  }

   /**
   * Stop using GPS listener
   * Calling this function will stop using GPS in your app
    * */
  public void stopUsingGPS(){

if(locationManager != null){
    if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

        return ;
    }
    locationManager.removeUpdates(GpsTracker.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(){
         try{
         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);
             isFromSetting = true;
            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();
       }catch(Exception e){e.printstacktrace}
      }

      @Override
     public void onLocationChanged(Location location) {
      }

      @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;
         }
        }
  • In you MainActivity.java do this
@Override
protected void onResume() {
    super.onResume();
  if (GPSTracker.isFromSetting==true){
            finish();
            startActivity(getIntent());
            GPSTracker.isFromSetting=false;
        }
     }
       @Override
        public void onBackPressed() {
          super.onBackPressed();
         if (GPSTracker.isFromSetting==true){
           finish();
            startActivity(getIntent());
            GPSTracker.isFromSetting=false;
           }
          }
      @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
       gps = new GPSTracker(LoginActivity.this);

    if(gps.canGetLocation()){

        double latitude = gps.getLatitude();
        double longitude = gps.getLongitude();

        Log.e("55",""+latitude);
        Log.e("56",""+longitude);
        Toast.makeText(getApplicationContext(), "Your Location is - \nLat: "                   
        + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
         }else{

            gps.showSettingsAlert(); 
          }
        }

Happy to help you :)




回答2:


Use below code for getting current location after enabling GPS ;

public class MainActivity extends AppCompatActivity implements LocationListener,
    GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener, OnMapReadyCallback {

final String TAG = "GPS";
GoogleMap googleMap;
Marker mCurrLocationMarker;
private long UPDATE_INTERVAL = 2 * 1000;  /* 10 secs */
private long FASTEST_INTERVAL = 2000; /* 2 sec */
static final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
private static final int GPS_CHECK = 112;
GoogleApiClient gac;
LocationRequest locationRequest;
TextView tvLatitude, tvLongitude, tvTime;
LocationManager locationManager;
Button capture;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tvLatitude = (TextView) findViewById(R.id.tvLatitude);
    tvLongitude = (TextView) findViewById(R.id.tvLongitude);
    tvTime = (TextView) findViewById(R.id.tvTime);
    capture = (Button) findViewById(R.id.capture);

    isGooglePlayServicesAvailable();

    //        if (!isLocationEnabled())
    //            showAlert();

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
        showAlert();
    }

    locationRequest = new LocationRequest();
    locationRequest.setInterval(UPDATE_INTERVAL);
    locationRequest.setFastestInterval(FASTEST_INTERVAL);
    locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    gac = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();

    SupportMapFragment mapFragment = (SupportMapFragment)
            getSupportFragmentManager()
                    .findFragmentById(R.id.map);

    mapFragment.getMapAsync(this);
}

@Override
protected void onStart() {
    gac.connect();
    super.onStart();
}

@Override
protected void onStop() {
    gac.disconnect();
    super.onStop();
}

@Override
public void onLocationChanged(Location location) {
    if (location != null) {
        updateUI(location);
    }
}

@Override
public void onConnected(@Nullable Bundle bundle) {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(MainActivity.this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);

        return;
    }
    Log.d(TAG, "onConnected");

    Location ll = LocationServices.FusedLocationApi.getLastLocation(gac);
    Log.d(TAG, "LastLocation: " + (ll == null ? "NO LastLocation" : ll.toString()));

    updateUI(ll);

    LocationServices.FusedLocationApi.requestLocationUpdates(gac, locationRequest, this);
}

@Override
public void onRequestPermissionsResult(
        int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

    switch (requestCode) {
        case MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(MainActivity.this, "Permission was granted!", Toast.LENGTH_LONG).show();

                try {
                    LocationServices.FusedLocationApi.requestLocationUpdates(
                            gac, locationRequest, this);
                } catch (SecurityException e) {
                    Toast.makeText(MainActivity.this, "SecurityException:\n" + e.toString(), Toast.LENGTH_LONG).show();
                }
            } else {
                Toast.makeText(MainActivity.this, "Permission denied!", Toast.LENGTH_LONG).show();
            }
            return;
        }
    }
}

@Override
public void onConnectionSuspended(int i) {
}

@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
    Toast.makeText(MainActivity.this, "onConnectionFailed: \n" + connectionResult.toString(),
            Toast.LENGTH_LONG).show();
    Log.d("DDD", connectionResult.toString());
}

private void updateUI(Location loc) {
    Log.d(TAG, "updateUI");
    try {
        tvLatitude.setText(Double.toString(loc.getLatitude()));
        tvLongitude.setText(Double.toString(loc.getLongitude()));
        tvTime.setText(DateFormat.getTimeInstance().format(loc.getTime()));

        double lattitude = loc.getLatitude();
        double longitude = loc.getLongitude();

        //Place current location marker
        LatLng latLng = new LatLng(lattitude, longitude);


        if(mCurrLocationMarker!=null){
            mCurrLocationMarker.setPosition(latLng);
        }else{
            mCurrLocationMarker = googleMap.addMarker(new MarkerOptions()
                    .position(latLng)
                    .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED))
                    .title("I am here"));
        }

        googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 18));
        googleMap.getUiSettings().setZoomControlsEnabled(true);
    }
    catch (Exception e)
    {

    }
}

private boolean isLocationEnabled() {
    LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
            locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

private boolean isGooglePlayServicesAvailable() {
    final int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;
    GoogleApiAvailability apiAvailability = GoogleApiAvailability.getInstance();
    int resultCode = apiAvailability.isGooglePlayServicesAvailable(this);
    if (resultCode != ConnectionResult.SUCCESS) {
        if (apiAvailability.isUserResolvableError(resultCode)) {
            apiAvailability.getErrorDialog(this, resultCode, PLAY_SERVICES_RESOLUTION_REQUEST)
                    .show();
        } else {
            Log.d(TAG, "This device is not supported.");
            finish();
        }
        return false;
    }
    Log.d(TAG, "This device is supported.");
    return true;
}

private void showAlert() {
    final AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Enable Location")
            .setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " +
                    "use this app")
            .setPositiveButton("Location Settings", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                    startActivityForResult(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS), GPS_CHECK);
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {

                }
            });
    dialog.show();
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == GPS_CHECK) {
        if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
            capture.setVisibility(View.GONE);
            Toast.makeText(getApplicationContext(), "Please turn on gps...", Toast.LENGTH_SHORT).show();
            Log.e("BBBBBBBBBBBBBBB", "");
        }
        else
        {
            gac.connect();
            googleMap.setOnMyLocationButtonClickListener(new GoogleMap.OnMyLocationButtonClickListener() {

                @Override
                public boolean onMyLocationButtonClick()
                {
                    try
                    {
                        Location myLocation = googleMap.getMyLocation();
                        onLocationChanged(myLocation);
                    }
                    catch (Exception e)
                    {
                        Log.getStackTraceString(e);
                    }
                    return false;
                }
            });
        }
    }

}

@Override
public void onMapReady(GoogleMap map) {
    googleMap = map;
    map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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;
    }
    map.setMyLocationEnabled(true);
    map.setTrafficEnabled(true);
    map.setIndoorEnabled(true);
    map.setBuildingsEnabled(true);
    map.getUiSettings().setZoomControlsEnabled(true);
}
}



回答3:


you can use thread or service with some time interval and get lat long in that thread or service. somthing like this.

  mHandler=new Handler();
    mRunnable=new Runnable() {
        @Override
        public void run() {get your lat long here


            mHandler.postDelayed(this,DELAY_TIME);
        }
    };

    mHandler.postDelayed(mRunnable,DELAY_TIME);



回答4:


after returning back to activity by using on resume flag try recreating activity then use delay in oncreate() that worked fine for me. in on create after returning to activity i use below code.

final Handler handler = new Handler();
          handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                // Do something after 5s = 5000ms
                gps = new GPSTracker(MainActivity.this);
                if(gps.canGetLocation()){

                    double latitude = gps.getLatitude();
                    double longitude = gps.getLongitude();
                    sessionDepth = 0;
                    // \n is for new line
                    Toast.makeText(getApplicationContext(), "Your Location 
is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
                }
            }
        }, 4000);



回答5:


Another better way would be using broadcast listener SO solution provided here. Have a look and let me know.



来源：https://stackoverflow.com/questions/46321106/after-enable-gps-from-an-app-prompt-how-to-refresh-and-get-the-current-location

标签
android
android-location
android-gps
location-services
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