尝试在空对象引用上调用虚拟方法“double android.location.Location.getLatitude()”，在下面这一行中显示错误
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【中文标题】尝试在空对象引用上调用虚拟方法“double android.location.Location.getLatitude()”，在下面这一行中显示错误【英文标题】：Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference showing error in this line bellow 【发布时间】：2021-06-19 07:15:19 【问题描述】：在这一行显示错误 我能做什么 在这一行显示错误 我能做什么 在这一行显示错误 我能做什么 在这一行显示错误 我能做什么 在这一行显示错误 我能做什么显示错误在这一行中我能做什么在这一行中显示错误我能在这一行中显示错误我能在这一行中显示错误我能做什么在这一行中显示错误我能做什么在这一行中显示错误我能做什么我确实在这一行显示错误我该怎么办
LatLng userLatLng = new LatLng(location.getLatitude(),location.getLongitude());
import android.Manifest;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.icu.text.Replaceable;
import android.location.Location;
import android.os.Bundle;
import android.os.Looper;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import com.example.easyride.R;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MapStyleOptions;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.karumi.dexter.Dexter;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionDeniedResponse;
import com.karumi.dexter.listener.PermissionGrantedResponse;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.single.PermissionListener;
import java.util.ResourceBundle;
public class HomeFragment extends Fragment implements OnMapReadyCallback
private GoogleMap mMap;
private HomeViewModel homeViewModel;
//Location
private FusedLocationProviderClient fusedLocationProviderClient;
private LocationRequest locationRequest;
private LocationCallback locationCallback;
SupportMapFragment mapFragment;
@Override
public void onDestroy()
fusedLocationProviderClient.removeLocationUpdates(locationCallback);
super.onDestroy();
public View onCreateView(@NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState)
homeViewModel = new ViewModelProvider(this).get(HomeViewModel.class);
View root = inflater.inflate(R.layout.fragment_home, container, false);
init();
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
return root;
private void init()
locationRequest = new LocationRequest();
locationRequest.setSmallestDisplacement(10f);
locationRequest.setInterval(5000);
locationRequest.setFastestInterval(3000);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationCallback = new LocationCallback()
@Override
public void onLocationResult(@NonNull LocationResult locationResult)
super.onLocationResult(locationResult);
LatLng newPosition = new LatLng(locationResult.getLastLocation().getLatitude(),
locationResult.getLastLocation().getLongitude());
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(newPosition, 18f));
;
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(getContext());
if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getContext(), 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;
fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallback, Looper.myLooper());
@Override
public void onMapReady(GoogleMap googleMap)
mMap = googleMap;
//Check Permission
Dexter.withContext(getContext())
.withPermission(Manifest.permission.ACCESS_FINE_LOCATION)
.withListener(new PermissionListener()
@Override
public void onPermissionGranted(PermissionGrantedResponse permissionGrantedResponse)
if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getContext(), 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;
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
mMap.setOnMyLocationButtonClickListener(() ->
fusedLocationProviderClient.getLastLocation()
.addOnFailureListener(e -> Toast.makeText(getContext(), ""+e.getMessage(), Toast.LENGTH_SHORT).show())
.addOnSuccessListener(location ->
LatLng userLatLng = new LatLng(location.getLatitude(),location.getLongitude());
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(userLatLng,18f));
);
return true;
);
//Set layout button
View locationButton = ((View)mapFragment.getView().findViewById(Integer.parseInt("1"))
.getParent())
.findViewById(Integer.parseInt("2"));
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) locationButton.getLayoutParams();
//Right bottom
params.addRule(RelativeLayout.ALIGN_PARENT_TOP,0);
params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM,RelativeLayout.TRUE);
params.setMargins(0,0,0,50);
@Override
public void onPermissionDenied(PermissionDeniedResponse permissionDeniedResponse)
Toast.makeText(getContext(), "Permission"+permissionDeniedResponse.getPermissionName()+""+
"was denied!",Toast.LENGTH_SHORT).show();
@Override
public void onPermissionRationaleShouldBeShown(PermissionRequest permissionRequest, PermissionToken permissionToken)
).check();
try
boolean success = googleMap.setMapStyle(MapStyleOptions.loadRawResourceStyle(getContext(),R.raw.uber_maps_style));
if (!success)
Log.e("EDMT_ERROR","Style parsing error");
catch (Resources.NotFoundException e)
Log.e("EDMT_ERROR",e.getMessage());
```
【问题讨论】：
请避免在您的问题中重复文字。 【参考方案1】：使用此代码
import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.IntentSender;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.icu.text.Replaceable;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Looper;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import com.example.uber.R;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.PendingResult;
import com.google.android.gms.common.api.Status;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.location.LocationSettingsRequest;
import com.google.android.gms.location.LocationSettingsResult;
import com.google.android.gms.location.LocationSettingsStatusCodes;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MapStyleOptions;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.karumi.dexter.Dexter;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionDeniedResponse;
import com.karumi.dexter.listener.PermissionGrantedResponse;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.single.PermissionListener;
import java.util.Locale;
import java.util.ResourceBundle;
public class HomeFragment extends Fragment implements OnMapReadyCallback
private GoogleMap mMap;
private HomeViewModel homeViewModel;
private int requestCode;
//Location
private FusedLocationProviderClient fusedLocationProviderClient;
private LocationRequest locationRequest;
private LocationCallback locationCallback;
SupportMapFragment mapFragment;
@Override
public void onDestroy()
fusedLocationProviderClient.removeLocationUpdates(locationCallback);
super.onDestroy();
public View onCreateView(@NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState)
homeViewModel = new ViewModelProvider(this).get(HomeViewModel.class);
View root = inflater.inflate(R.layout.fragment_home, container, false);
init();
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
return root;
@SuppressLint("MissingPermission")
private void init()
GoogleApiClient googleApiClient = new GoogleApiClient.Builder(getContext())
.addApi(LocationServices.API).build();
googleApiClient.connect();
locationRequest = new LocationRequest();
locationRequest.setSmallestDisplacement(10f);
locationRequest.setInterval(10000);
locationRequest.setFastestInterval(10000 / 2);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder().addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
PendingResult<LocationSettingsResult> result = LocationServices.SettingsApi.checkLocationSettings(googleApiClient, builder.build());
result.setResultCallback(result1 ->
final Status status = result1.getStatus();
if (((Status) status).getStatusCode() == LocationSettingsStatusCodes.RESOLUTION_REQUIRED)
try
status.startResolutionForResult((Activity) getContext(), requestCode);
catch (IntentSender.SendIntentException ignored)
);
locationCallback = new LocationCallback()
@Override
public void onLocationResult(@NonNull LocationResult locationResult)
super.onLocationResult(locationResult);
LatLng newPosition = new LatLng(locationResult.getLastLocation().getLatitude(),
locationResult.getLastLocation().getLongitude());
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(newPosition, 18f));
;
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(getContext());
fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallback, Looper.myLooper());
@Override
public void onMapReady(GoogleMap googleMap)
mMap = googleMap;
//Check Permission
Dexter.withContext(getContext())
.withPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
.withListener(new PermissionListener()
private void onSuccess(Location location)
LatLng userLatLng = new LatLng(location.getLatitude(), location.getLongitude());
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(userLatLng, 18f));
@SuppressLint("MissingPermission")
@Override
public void onPermissionGranted(PermissionGrantedResponse permissionGrantedResponse)
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
mMap.setOnMyLocationButtonClickListener(() ->
fusedLocationProviderClient.getLastLocation()
.addOnFailureListener(e -> Toast.makeText(getContext(), "" + e.getMessage(), Toast.LENGTH_SHORT).show())
.addOnSuccessListener(this::onSuccess);
return true;
);
//Set layout button
View locationButton = ((View)mapFragment.getView().findViewById(Integer.parseInt("1"))
.getParent())
.findViewById(Integer.parseInt("2"));
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) locationButton.getLayoutParams();
//Right bottom
params.addRule(RelativeLayout.ALIGN_PARENT_TOP,0);
params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM,RelativeLayout.TRUE);
params.setMargins(0,0,0,50);
@Override
public void onPermissionDenied(PermissionDeniedResponse permissionDeniedResponse)
Toast.makeText(getContext(), "Permission"+permissionDeniedResponse.getPermissionName()+""+
"was denied!",Toast.LENGTH_SHORT).show();
@Override
public void onPermissionRationaleShouldBeShown(PermissionRequest permissionRequest, PermissionToken permissionToken)
).check();
try
boolean success = googleMap.setMapStyle(MapStyleOptions.loadRawResourceStyle(getContext(), R.raw.uber_maps_style));
if (!success)
Log.e("EDMT_ERROR","Style parsing error");
catch (Resources.NotFoundException e)
Log.e("EDMT_ERROR",e.getMessage());
【讨论】：
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