AndroidでLastKnownLocationを取得するとnullが返されます

Question

lastknownの場所を取得しようとしていますが、null値を与えています。私はGPSが有効かどうかをテストしましたが、それは真実を返します。

私はGoogleマップに入り、私の場所を指していましたが（場所のデータがクリアされているかもしれないと思っていましたが）、まだ動作しませんでした。ここで

は私のコード

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
      return; 
     } 
     boolean isgps=locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 
     Log.v("is GPs Enabled",isgps+""); 
     Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER); 
     updateNewLocation(location); 
    } 

    private void updateNewLocation(Location location) { 
     TextView myLocationText=(TextView)findViewById(R.id.myLocation); 
     if(location!=null){ 
      double lat=location.getLatitude(); 
      double lng=location.getLongitude(); 
      myLocationText.setText("lat:"+lat+"\nlong:"+lng); 
      Log.v("Location","lat:"+lat+"\nlong:"+lng); 
     } 
    } 

Answer 1

あるハイテクなぜgetLastKnownLocationを使用しようとすると、以前の緯度を返します.ITとlongitude.Mostは、おそらくそれはあなたをretrun null.Itを更新し、それが以前の緯度LNGを返すために時間がかかりますそれは非常に古いか新しい古いかもしれません。正確ではなく、正確です。だから、あなたは新しいアプローチの方がいいですよ。

私はちょうどあなたを参照していますgoogleフュージョンapiどのような種類の更新や最新の。それは非常に正確です。

あなたのプロジェクトでAPIを融合させる方法。私はあなたに小さな例を挙げます。

ステップ1.

public class GoogleLocationService { 
private GoogleServicesCallbacks callbacks = new GoogleServicesCallbacks(); 
LocationUpdateListener locationUpdateListener; 
Context activity; 
protected GoogleApiClient mGoogleApiClient; 
protected LocationRequest mLocationRequest; 

public static final long UPDATE_INTERVAL_IN_MILLISECONDS = 30000; 


public GoogleLocationService(Context activity, LocationUpdateListener locationUpdateListener) { 
    this.locationUpdateListener = locationUpdateListener; 
    this.activity = activity; 
    buildGoogleApiClient(); 
} 

protected synchronized void buildGoogleApiClient() { 
    //Log.i(TAG, "Building GoogleApiClient"); 
    mGoogleApiClient = new GoogleApiClient.Builder(activity) 
      .addConnectionCallbacks(callbacks) 
      .addOnConnectionFailedListener(callbacks) 
      .addApi(LocationServices.API) 
      .build(); 
    createLocationRequest(); 
    mGoogleApiClient.connect(); 
} 

protected void createLocationRequest() { 
    mLocationRequest = new LocationRequest(); 
    mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS); 
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY); 

} 

private class GoogleServicesCallbacks implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener { 

    @Override 
    public void onConnected(Bundle bundle) { 
     startLocationUpdates(); 
    } 

    @Override 
    public void onConnectionSuspended(int i) { 
     mGoogleApiClient.connect(); 
    } 

    @Override 
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) { 

     if (connectionResult.getErrorCode() == ConnectionResult.SERVICE_VERSION_UPDATE_REQUIRED) { 
      Toast.makeText(activity, "Google play service not updated", Toast.LENGTH_LONG).show(); 

     } 
     locationUpdateListener.cannotReceiveLocationUpdates(); 
    } 

    @Override 
    public void onLocationChanged(Location location) { 
     if (location.hasAccuracy()) { 
      if (location.getAccuracy() < 30) { 
       locationUpdateListener.updateLocation(location); 
      } 
     } 
    } 
} 

private static boolean locationEnabled(Context context) { 
    boolean gps_enabled = false; 
    LocationManager lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE); 
    try { 
     gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER); 
    } catch (Exception ex) { 
     ex.printStackTrace(); 
    } 
    return gps_enabled; 
} 

private boolean servicesConnected(Context context) { 
    return isPackageInstalled(GooglePlayServicesUtil.GOOGLE_PLAY_STORE_PACKAGE, context); 
} 

private boolean isPackageInstalled(String packagename, Context context) { 
    PackageManager pm = context.getPackageManager(); 
    try { 
     pm.getPackageInfo(packagename, PackageManager.GET_ACTIVITIES); 
     return true; 
    } catch (PackageManager.NameNotFoundException e) { 
     e.printStackTrace(); 
     return false; 
    } 
} 


public void startUpdates() { 
    /* 
    * Connect the client. Don't re-start any requests here; instead, wait 
    * for onResume() 
    */ 
    if (servicesConnected(activity)) { 
     if (locationEnabled(activity)) { 
      locationUpdateListener.canReceiveLocationUpdates(); 
      startLocationUpdates(); 
     } else { 
      locationUpdateListener.cannotReceiveLocationUpdates(); 
      Toast.makeText(activity, "Unable to get your location.Please turn on your device Gps", Toast.LENGTH_LONG).show(); 
     } 
    } else { 
     locationUpdateListener.cannotReceiveLocationUpdates(); 
     Toast.makeText(activity, "Google play service not available", Toast.LENGTH_LONG).show(); 
    } 
} 

//stop location updates 
public void stopUpdates() { 
    stopLocationUpdates(); 
} 

//start location updates 
private void startLocationUpdates() { 

    if (checkSelfPermission(activity, ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(activity, ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
     return; 
    } 
    if (mGoogleApiClient.isConnected()) { 
     LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, callbacks); 
    } 
} 

public void stopLocationUpdates() { 
    if (mGoogleApiClient.isConnected()) { 
     LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, callbacks); 
    } 
} 

public void startGoogleApi() { 
    mGoogleApiClient.connect(); 
} 

public void closeGoogleApi() { 
    mGoogleApiClient.disconnect(); 
} 

} 

ステップ2 GoogleLocationService.javaこのクラスを作成します。このインタフェース LocationUpdateListener.java

public interface LocationUpdateListener { 

/** 
* Called immediately the service starts if the service can obtain location 
*/ 
void canReceiveLocationUpdates(); 

/** 
* Called immediately the service tries to start if it cannot obtain location - eg the user has disabled wireless and 
*/ 
void cannotReceiveLocationUpdates(); 

/** 
* Called whenever the location has changed (at least non-trivially) 
* @param location 
*/ 
void updateLocation(Location location); 

/** 
* Called when GoogleLocationServices detects that the device has moved to a new location. 
* @param localityName The name of the locality (somewhere below street but above area). 
*/ 
void updateLocationName(String localityName, Location location); 
} 

ステップ3.あなたが場所

private GoogleLocationService googleLocationService; 

googleLocationService = new GoogleLocationService(context, new LocationUpdateListener() { 
    @Override 
    public void canReceiveLocationUpdates() { 
    } 

    @Override 
    public void cannotReceiveLocationUpdates() { 
    } 

    //update location to our servers for tracking purpose 
    @Override 
    public void updateLocation(Location location) { 
     if (location != null) { 
      Timber.e("updated location %1$s %2$s", location.getLatitude(), location.getLongitude()); 

     } 
    } 

    @Override 
    public void updateLocationName(String localityName, Location location) { 

     googleLocationService.stopLocationUpdates(); 
    } 
}); 
googleLocationService.startUpdates(); 


and call this onDestroy 
if (googleLocationService != null) { 
    googleLocationService.stopLocationUpdates(); 
} 

おかげでこのヘルプあなたを願って取得したいコードのこの部分を確認します。