在Android上获取当前位置

Question

我想找出我的位置当前在连接到计算机的设备上的位置，但是由于我的位置没有更改，因此它不属于onLocationChanged函数，因此返回location = null。如何输入onLocationChanged函数？

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

        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.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 15));
            }
            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {
            }

            @Override
            public void onProviderEnabled(String s) {
            }

            @Override
            public void onProviderDisabled(String s) {
            }
        };

Answer 1

[像塞伊建议的那样，您可以使用融合的位置提供程序来检索设备的last known location，它将显示您的当前位置。

查看下面的工作代码示例：

import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.FragmentActivity;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
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.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private FusedLocationProviderClient fusedLocationClient;
    private GoogleMap mMap;

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

        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        if (mapFragment != null) {
            mapFragment.getMapAsync(this);
        }
    }

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

        if (checkPermissions()) {
            mMap.setMyLocationEnabled(true);
        }

        fusedLocationClient.getLastLocation()
                .addOnSuccessListener(this, new OnSuccessListener<Location>() {
                    @Override
                    public void onSuccess(Location location) {
                        if (location != null) {
                            System.out.println("current location: " + location.toString());
                        } else {
                            System.out.println("current location is null");
                        }
                    }
                }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                System.out.println("error trying to get current location");
                e.printStackTrace();
            }
        });
    }

    private boolean checkPermissions() {
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            return true;
        } else {
            requestPermissions();
            return false;
        }
    }

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

希望有帮助！