无法从播放服务获取位置更新

Question

我正在尝试从我的 Android 应用上的 google play 服务请求位置更新。到目前为止，如果我先启动谷歌地图，我可以获得最后一个位置，但无法获得任何更新。

public class Inbox extends AppCompatActivity implements
GoogleApiClient.ConnectionCallbacks, 
GoogleApiClient.OnConnectionFailedListener,
com.google.android.gms.location.LocationListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        int r = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(this);
        if(r != 0){
            System.out.println(r);
            Dialog d = GoogleApiAvailability.getInstance().getErrorDialog(this,r,1);
            d.show();
        }
        if (mGoogleApiClient == null) {
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .addApi(AppIndex.API).build();
        }
        mGoogleApiClient.connect();
        super.onStart();
    }

    @Override
    public void onConnected(Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            System.out.println("Problem with rights");
        }
        else{
            Location mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
            LocationRequest mLocationRequest = new LocationRequest();

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

            if(mLastLocation != null){
                System.out.println(mLastLocation.toString());
            }
            else {
                System.out.println("No location cached");
            }
            LocationAvailability a = LocationServices.FusedLocationApi.getLocationAvailability(mGoogleApiClient);
            System.out.println(a);
        }
    }


    @Override
    public void onConnectionSuspended(int i) {
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
    }
    @Override
    public void onLocationChanged(Location location) {
        System.out.println(location.toString());
    }




    @Override
    public void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
        Action viewAction = Action.newAction(...);
        AppIndex.AppIndexApi.start(mGoogleApiClient, viewAction);
    }

    @Override
    public void onStop() {
        super.onStop();
        Action viewAction = Action.newAction(...);
        AppIndex.AppIndexApi.end(mGoogleApiClient, viewAction);
        mGoogleApiClient.disconnect();
    }

}

当我在使用谷歌地图后启动应用程序时，我会从以下位置获取最后缓存的位置：

LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

但之后，我打印出位置服务不可用：

LocationAvailability a = LocationServices.FusedLocationApi.getLocationAvailability(mGoogleApiClient);
System.out.println(a);

永远不会调用onLocationChanged/onConnectionFailed/onConnectionSuspended。

我在 Genymotion 上使用 android 5.1.0 的虚拟 Nexus 6 上运行我的应用程序。

Answer 1

我认为您在这里遗漏了一些东西。在您的 onCennected 回调中，您必须首先检查是否可以获得最后一个已知位置。如果它不可用，那么您必须请求位置更新。重构你的 onConnected 如下所示，它应该可以正常工作

@Override
    public void onConnected(Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this, 
           Manifest.permission.ACCESS_FINE_LOCATION) != 
           PackageManager.PERMISSION_GRANTED && 
           ActivityCompat.checkSelfPermission(this, 
           Manifest.permission.ACCESS_COARSE_LOCATION) != 
           PackageManager.PERMISSION_GRANTED) {
               System.out.println("Problem with rights");
        } else {

           Location lastLocation = LocationServices.FusedLocationApi
                                       .getLastLocation(mGoogleApiClient);

           if (lastLocation != null) {
            //you have a location. use that here. no need to request for location 
            // updates
            mGoogleApiClient.disconnect();
           } else {
            //you have to request for location
             mLocationRequest = LocationRequest.create();
             mLocationRequest.setInterval(2000);
             mLocationRequest.setFastestInterval(1000);
             mLocationRequest.setSmallestDisplacement(50);
             mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
             LocationServices.FusedLocationApi
               .requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

           }

        }
    }

然后在您的 locationChanged 回调中执行以下操作

@Override
public void onLocationChanged(Location location) {

    //now that we got the initial location. it is time to stop the api client
    LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
    mGoogleApiClient.disconnect();

   // use your newly obtained location here

}

注意：如果您在 GenyMotion 上尝试此操作。通过在 GM 模拟器上启用 GPS 确保它可以接收位置