Android：爲什麼get方法getLatitude（）和getLongtitude（）返回null？

我想獲取2個變量的位置，但它返回null。我不知道我在做什麼錯。如果我想開始活動，它自己停止。這裏是我的代碼：Android：爲什麼get方法getLatitude（）和getLongtitude（）返回null？

private GoogleMap mMap; 
LocationManager myLocationManager; 
Location myLocation; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_pechhulp); 
    // Obtain the SupportMapFragment and get notified when the map is ready to be used. 
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
      .findFragmentById(R.id.map); 
    mapFragment.getMapAsync(this); 

    myLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
    if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
     return; 
    } 
    myLocation = myLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER); 

} 


@Override 
public void onMapReady(GoogleMap googleMap) { 
    mMap = googleMap; 

    // Pak de Latitude en Longtitude van de aangemaakte locatie. 
    // These variables are returning null 
    double latitude = myLocation.getLatitude(); 
    double longtitude = myLocation.getLongitude(); 

    // Add a marker in Sydney and move the camera 
    LatLng sydney = new LatLng(-34, 151); 
    LatLng myPosition = new LatLng(latitude, longtitude); 

    mMap.addMarker(new MarkerOptions().position(sydney).title("Dit is uw plaats")); 
    mMap.moveCamera(CameraUpdateFactory.newLatLng(myPosition)); 
}

，這裏是錯誤：

                    java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference

來源

2016-07-10 Stackingcoder

你必須要檢查的權限塊，因爲myLocations總是空。致電getLatitude()和getLongitude()之前致電onRequestPermissionsResult。

請檢查：Requesting Permissions at Run Time

來源

2016-07-10 20:06:33

Android：爲什麼get方法getLatitude（）和getLongtitude（）返回null？

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