带有FragmentActivity的getContext()和getActivity() [英] getContext() and getActivity() with FragmentActivity

问题描述

我需要在FragmentActivity中使用getActivity()和getContext()方法.怎么做?我不能扩展Fragment类(我现在不能做).也许我可以投下其他东西.需要在本堂课上做.

I need to use getActivity() and getContext() methods with FragmentActivity. How to make it? I can't extends Fragment class(i can't to do now). Maybe I can cast or something else. Need to do it in this class.

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;
    private LatLng latLng;
    private Marker currLocationMarker;
    private GoogleMap mMap;

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

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

    private synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this.getContext())
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    public void onConnected(@Nullable Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this.getContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) !=
                PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this.getContext(), android.Manifest.permission.ACCESS_COARSE_LOCATION) !=
                PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(getActivity(),
                    new String[]{
                            android.Manifest.permission.READ_EXTERNAL_STORAGE,
                            android.Manifest.permission.WRITE_EXTERNAL_STORAGE,
                            android.Manifest.permission.ACCESS_FINE_LOCATION

                    },
                    100);
            return;
        }
        Location mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);
        if (mLastLocation != null) {
            //place marker at current position
            //mGoogleMap.clear();
            latLng = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
            MarkerOptions markerOptions = new MarkerOptions();
            markerOptions.position(latLng);
            markerOptions.title("Current Position");
            markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
            currLocationMarker = mMap.addMarker(markerOptions);
            CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(latLng, 5);
            mMap.animateCamera(yourLocation);
        }

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(5000); //5 seconds
        mLocationRequest.setFastestInterval(3000); //3 seconds
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
        //mLocationRequest.setSmallestDisplacement(0.1F); //1/10 meter
    }
}

推荐答案

getActivity()和getContext()严格是Fragment方法.由于FragmentActivity类扩展了Activity类，因此分别为"this"和"getApplicationContext()".

getActivity() and getContext() are strictly Fragment methods. Since the FragmentActivity class extends the Activity class, the alternatives are 'this' and 'getApplicationContext()' respectively.

例如

mGoogleApiClient = new GoogleApiClient.Builder(this.getContext())

可以简单地变成

mGoogleApiClient = new GoogleApiClient.Builder(getApplicationContext())

这篇关于带有FragmentActivity的getContext()和getActivity()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！