android - FusedLocationApi.getLastLocation 返回 null

Question

我有定位服务的单例

public class LocationService implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    public static final String TAG = LocationService.class.getSimpleName();

    private static LocationService instance;
    private LocationRequest mLocationRequest;
    private GoogleApiClient mGoogleApiClient;
    public Location location;
    private Context context;

    private LocationService (Context context) {

        this.context = context;

        mGoogleApiClient = new GoogleApiClient.Builder(context)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        mGoogleApiClient.connect();

        mLocationRequest = LocationRequest.create()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                .setInterval(10 * 1000)        // 10 seconds, in milliseconds
                .setFastestInterval(60 * 1000); // 1 second, in milliseconds

    }

    public static LocationService getInstance(Context context){

        if (null == instance){
            instance = new LocationService(context);
        }
        return instance;
    }

    @Override
    public void onConnected(Bundle bundle) {
        Log.i(TAG, "Location services connected.");

        if (ActivityCompat.checkSelfPermission(this.context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this.context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

        this.location = location;

        if (location != null) {
            Log.d(TAG, location.toString());
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(TAG, "Location services suspended. Please reconnect.");
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
    }

    public void onLocationChanged(Location location) {

        this.location = location;

        Log.i(TAG, "Location changed.");
        Log.i(TAG, location.toString());

    }
}

我通过调用 onCreate 在 MainActivity 中启动它

LocationService locationService = LocationService.getInstance(getApplicationContext());

但我的位置始终为空并且 onLocationChanged 不会被调用

OnConnected 正在被调用，我检查了调试器，但是 location 里面是空的

我做错了什么？

Answer 1

如果您的最后一个位置为空，您需要至少注册一次以获取更新，以获取第一个最后位置。

Check the documentation 对于“请求位置更新”。