从应用程序提示启用 gps 后如何刷新并获取当前位置？

Question

我目前正在开发一个 Android 应用程序，如果它没有打开，它会提示用户启用 GPS，我为此使用了警报对话框。在我从设置中启用 GPS 并通过按返回按钮返回到我的应用程序后，吐司消息显示 0.00,0.00。虽然如果我在运行应用程序之前打开 GPS，应用程序会正确显示我的位置。我想知道启用 GPS 后使用哪种方法刷新用户位置。任何相关文章都会很有帮助。

这是我的 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;
}

}

Answer 1

启用 GPS 后使用以下代码获取当前位置；

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);
}
}

Answer 2

试试这个我也遇到这个问题

你必须reload your activity
之后可以得到location
在gps tracker class

boolean

如果你想 enable or disable Gps，请确保 alert is in try catch to avoid crash。

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;
         }
        }

在你MainActivity.java这样做

@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(); 
          }
        }

很高兴为您提供帮助:)

Answer 3

您可以在某个时间间隔内使用线程或服务，并在该线程或服务中使用很长时间。像这样的东西。

  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);

Answer 4

通过使用恢复标志返回 activity 后尝试重新创建 activity 然后在 oncreate() 中使用延迟，这对我来说效果很好。在返回 activity 后创建时，我使用以下代码。

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);

Answer 5

另一种更好的方法是使用广播监听器SO solution provided here。看一看告诉我。

从应用程序提示启用 gps 后如何刷新并获取当前位置？

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

android

android-location

location-services

android-gps

很高兴为您提供帮助:)