当应用程序启动时，通过导航抽屉使用谷歌地图工作正常，但重新点击标签会产生非法异常错误

Question

如果我用不同的片段替换片段，其中映射片段在(在此代码示例MyFragment中)，然后返回，我得到一个

IllegalStateException

public class Home_Map extends Fragment {
 GoogleMap googleMap;
 FragmentManager myFragmentManager;
 SupportMapFragment mySupportMapFragment;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub
     View rootView = inflater.inflate(R.layout.fragment_home__map, container, false);
     //googleMap.setMyLocationEnabled(true);
        try {
            // Loading map
            initilizeMap();
            googleMap.setMyLocationEnabled(true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    return rootView;
}
 private void initilizeMap() {
        try
        {
        if (googleMap == null) {
            myFragmentManager = getFragmentManager();
            mySupportMapFragment = (SupportMapFragment)myFragmentManager.findFragmentById(R.id.map2);
            googleMap = mySupportMapFragment.getMap();
            if (googleMap == null) {
                Toast.makeText(getActivity().getApplicationContext(),
                        "Sorry! unable to create maps", Toast.LENGTH_SHORT)
                        .show();
            }
        }
        } catch (Exception e) { Toast.makeText(getActivity().getApplicationContext(), ""+e, 1).show();
            // TODO: handle exception
        }
    }
   @Override
    public void onResume() {
        super.onResume();
        initilizeMap();
    }
   @Override
    public void onDetach() {
        // TODO Auto-generated method stub
        super.onDetach();
          try {
                Field childFragmentManager = Fragment.class
                        .getDeclaredField("mChildFragmentManager");
                childFragmentManager.setAccessible(true);
                childFragmentManager.set(this, null);
            } catch (NoSuchFieldException e) {
                throw new RuntimeException(e);
            } catch (IllegalAccessException e) {
                throw new RuntimeException(e);
            }
    }
    }

Answer 1

更改时需要release the memory

尝试使用以下代码:

public class Home_Map extends Fragment {

    private MapView mapView;
    public static MapsFragment newInstance() {
        MapsFragment fragment = new MapsFragment();
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.mapview, container, false);
        // Gets the MapView from the XML layout and creates it
        MapsInitializer.initialize(getActivity());

        switch (GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity())) {
            case ConnectionResult.SUCCESS:
                Toast.makeText(getActivity(), "SUCCESS", Toast.LENGTH_SHORT).show();
                mapView = (MapView) v.findViewById(R.id.map);
                mapView.onCreate(savedInstanceState);
                // Gets to GoogleMap from the MapView and does initialization stuff
                if (mapView != null) {
                     mapView.getMapAsync(new OnMapReadyCallback() {
                        @Override
                        public void onMapReady(GoogleMap googleMap) {
                            googleMap.getUiSettings().setMyLocationButtonEnabled(true);
                            googleMap.setMyLocationEnabled(true);
                            CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(43.1, -87.9), 10);
                            googleMap.animateCamera(cameraUpdate);
                        }
                    });
                }
                break;
            case ConnectionResult.SERVICE_MISSING:
                Toast.makeText(getActivity(), "SERVICE MISSING", Toast.LENGTH_SHORT).show();
                break;
            case ConnectionResult.SERVICE_VERSION_UPDATE_REQUIRED:
                Toast.makeText(getActivity(), "UPDATE REQUIRED", Toast.LENGTH_SHORT).show();
                break;
            default:
                Toast.makeText(getActivity(), GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity()), Toast.LENGTH_SHORT).show();
        }
        return v;
    }
    @Override
    public void onResume() {
        mapView.onResume();
        super.onResume();
    }
    @Override
    public void onDestroy() {
        super.onDestroy();
        mapView.onDestroy();
    }
    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mapView.onLowMemory();
    }
}

布局xml文件是:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent">
    <com.google.android.gms.maps.MapView
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name=".MapsFragment"/>
</RelativeLayout>

请注意，您应该在DrawerLayout文件和Home_Map文件上同时添加import android.support.v4.app.Fragment;。

最后使用

fragment = MapsFragment.newInstance();

代替

fragment = new Home_Map();

在你的DrawerLayout .

你也可以在这里试试我的项目