Google Map无法定位当前设备位置且不显示经纬度求助

我想要实现Activity启动时，地图自动缩放至当前设备位置，同时显示当前位置的经纬度，但实际运行时地图停在(0,0)位置，既不缩放也不显示经纬度。以下是我的实现代码：

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback { 
    private GoogleMap mMap; 
    private static final int REQUEST_LOCATION = 1; 
    LocationManager locationManager; 
    Location location; 
    TextView latlngText; 
    Button refreshBtn; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.maps_layout); 
        // 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); 
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
        refreshBtn = (Button) findViewById(R.id.refreshbtn); 
        refreshBtn.setOnClickListener(new View.OnClickListener() { 
            @Override 
            public void onClick(View view) { 
                Intent intent = new Intent(MapsActivity.this, MapsActivity.class); 
                startActivity(intent); 
                finish(); 
            } 
        }); 
    } 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 
        mMap = googleMap; 
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID); 
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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); 
        getLocation(); 
    } 

    void getLocation() { 
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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; 
        }else { 
            Location location = locationManager.getLastKnownLocation(locationManager.NETWORK_PROVIDER); 
            if(location != null) { 
                double lat = location.getLatitude(); 
                double lng = location.getLongitude(); 
                latlngText = (TextView) findViewById(R.id.latlngText); 
                latlngText.setText("Latitude: " + lat + "\n" + "Longitude: " + lng); 
                LatLng coordinates = new LatLng(location.getLatitude(), location.getLongitude()); 
                mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(coordinates, 13.0f)); 
            } 
        } 
    } 

    @Override 
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 
        super.onRequestPermissionsResult(requestCode, permissions, grantResults); 
        switch (requestCode){ 
            case REQUEST_LOCATION: 
                getLocation(); 
                break; 
        } 
    } 
} 

你的代码有几个关键问题导致地图无法定位到当前位置，我帮你一步步修复：

1. 主动触发权限请求 #

你的代码只是检查了权限，但没有主动发起权限请求——如果用户还没授予位置权限，onMapReady会直接return，后续的getLocation()根本不会执行。修改onMapReady方法，当权限未授予时主动发起请求：

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

    // 检查位置权限
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED 
        && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // 主动请求权限
        ActivityCompat.requestPermissions(this, 
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 
                REQUEST_LOCATION);
        return;
    }
    mMap.setMyLocationEnabled(true);
    getLocation();
}

2. 处理getLastKnownLocation返回null的情况 #

getLastKnownLocation依赖设备缓存的位置信息，如果是第一次启动应用、设备刚开机，这个方法会返回null。我们需要添加LocationListener来监听实时位置更新作为 fallback：

首先在类中添加LocationListener变量：

private LocationListener locationListener;

然后修改getLocation方法，当缓存位置为空时注册位置监听：

void getLocation() {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED 
        && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, 
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 
                REQUEST_LOCATION);
        return;
    } else {
        Location location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
        if (location != null) {
            // 有缓存位置，直接更新UI
            updateLocationUI(location);
        } else {
            // 无缓存位置，注册监听获取实时位置
            locationListener = new LocationListener() {
                @Override
                public void onLocationChanged(Location location) {
                    updateLocationUI(location);
                    // 获取到位置后停止监听，节省资源
                    locationManager.removeUpdates(this);
                }

                @Override
                public void onStatusChanged(String provider, int status, Bundle extras) {}

                @Override
                public void onProviderEnabled(String provider) {}

                @Override
                public void onProviderDisabled(String provider) {}
            };
            // 注册网络和GPS位置更新监听
            locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 10, locationListener);
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 10, locationListener);
        }
    }
}

3. 提取UI更新逻辑到单独方法 #

把更新经纬度和地图缩放的逻辑抽出来，避免重复代码，同时提前初始化latlngText：

private void updateLocationUI(Location location) {
    double lat = location.getLatitude();
    double lng = location.getLongitude();
    // 只初始化一次TextView
    if (latlngText == null) {
        latlngText = findViewById(R.id.latlngText);
    }
    latlngText.setText("Latitude: " + lat + "\n" + "Longitude: " + lng);
    LatLng coordinates = new LatLng(lat, lng);
    mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(coordinates, 13.0f));
}

4. 确保Manifest配置正确 #

别忘了在AndroidManifest.xml中添加必要的权限和Google Maps配置：

<!-- 位置权限 -->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<!-- 网络权限（地图加载需要） -->
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<!-- Google Maps API Key 替换成你自己的 -->
<meta-data
    android:name="com.google.android.geo.API_KEY"
    android:value="YOUR_GOOGLE_MAPS_API_KEY" />

5. 优化刷新按钮逻辑（可选） #

现在的刷新按钮是重启Activity，其实直接调用getLocation()就能更新位置，更高效：

refreshBtn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        getLocation();
    }
});

内容的提问来源于stack exchange，提问作者Basil Shaikh