Question

每次我想开始地图活动时，它都崩溃了，然后我在Sentry中出现了这个错误

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

以下是活动：

package something;

import android.*;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.widget.Toast;

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.MarkerOptions;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

    LocationManager locationManager = null;

    LocationListener locationListener;

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

        if (requestCode == 1) {

            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                    {

                        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

                    }

                }

            }

        }

    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // 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);
    }



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

        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {

                LatLng userLocation = new LatLng(location.getLatitude(), location.getLongitude());

                mMap.clear();
                mMap.addMarker(new MarkerOptions().position(userLocation).title("Your Location"));
                mMap.moveCamera(CameraUpdateFactory.newLatLng(userLocation));


            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {

            }

            @Override
            public void onProviderEnabled(String s) {

            }

            @Override
            public void onProviderDisabled(String s) {

            }
        };

        if (Build.VERSION.SDK_INT < 23) {

            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

        } else {

            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);

            } else {

                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

                Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

                LatLng userLocation = new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude());

                mMap.clear();

                mMap.addMarker(new MarkerOptions().position(userLocation).title("My Location"));
                mMap.moveCamera(CameraUpdateFactory.newLatLng(userLocation));



            }


        }


    }
}

Answer 1

尝试调用虚拟方法＆＃39; double android.location.Location.getLatitude（）＆＃39;在空对象引用上

您的 lastKnownLocation 是null。

if(lastKnownLocation != null)
{
           LatLng userLocation = new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude());

            mMap.clear();

            mMap.addMarker(new MarkerOptions().position(userLocation).title("My Location"));
            mMap.moveCamera(CameraUpdateFactory.newLatLng(userLocation));
}

getLatitude方法的NullPointerException

1 个答案: