android - Activity 开始时尝试获取当前位置

Question

我想在 Activity 开始时缩放到用户的当前位置。我有两个java类。其中一个是 MapActivity.java，另一个是 MapFragment.java。我正在尝试在 MapFragment.java 上完成这项工作。

  private Actvity activity;
  private volatile GoogleMap googleMap;
  GoogleApiClient mGoogleApiClient;
  LocationRequest mLocationRequest;

  @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    activity = getActivity();
}

MapFragment.java/onMapReady ;

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

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

    mGoogleApiClient.connect();

}

在这个 onMapReady 中，.addConnectionCallbacks(activity) 和 .addOnConnectionFailedListener(activity) 发出警告，如图所示；

enter image description here

在我分析过的示例中，他们在实现 GoogleApiClient.ConnectionCallbacks 和 GoogleApiCleint.OnConnectionFailedListener 而不是强制转换之前。不实现，我无法获得这些功能；

 @Override
public void onConnected(Bundle bundle) {

    mLocationRequest=LocationRequest.create();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

    mLocationRequest.setInterval(1000);

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

}

@Override
public void onConnectionSuspended(int i) {

}
 @Override
public void onConnectionFailed(ConnectionResult connectionResult) {

}

而且我还必须获取 LocationListeners 的方法；

@Override
public void onLocationChanged(Location location) {
    if(location == null){
        Toast.makeText(this,"Cant get current location",Toast.LENGTH_LONG).show();

    }
    else{
        LatLng ll= new LatLng(location.getLatitude(),location.getLongitude());
        CameraUpdate update= CameraUpdateFactory.newLatLngZoom(ll,15);
        mGoogleMap.animateCamera(update);
    }
}

如果我在 fragment 中手动实现它们，会导致任何问题吗？在 fragment Activity 中获取当前位置的正确方法是什么？

Answer 1

If I implement them by hand in the fragment, does it cause any problem?

没有。您需要做的就是实现 ConnectionCallbacks 和 OnConnectionFailedListener。

What is the proper way to get current location in fragment activity?

public class MyFragment extends Fragment implements
        ConnectionCallbacks, OnConnectionFailedListener {

    // Create an instance of GoogleAPIClient.
    if (mGoogleApiClient == null) {
    mGoogleApiClient = new GoogleApiClient.Builder(this)
        .addConnectionCallbacks(this)
        .addOnConnectionFailedListener(this)
        .addApi(LocationServices.API)
        .build();
    }

    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }
   @Override
   public void onConnected(Bundle connectionHint) {
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient); // this is your location
        if (mLastLocation != null) {              
         mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
       mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
        }
    }
}

Reference