Question

我有一个活动，可以从我的自定义片段中显示googleMap。每个东西都显示正确，但是当我点击此Activity的Back Button时，会出现一条android错误警告消息和'java.lang.RuntimeException：无法销毁活动（... myActivity}：java.lang.NullPointerException'。logcat没有任何指向我的代码中的任何地方，我找不到问题的根源。

这里是logcat：

06-04 06:41:04.206  30479-30479/xxx E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to destroy activity {xxx.InfoActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3624)
        at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3642)
        at android.app.ActivityThread.access$1200(ActivityThread.java:156)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1393)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:153)
        at android.app.ActivityThread.main(ActivityThread.java:5299)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
        at com.google.maps.api.android.lib6.d.ai.d(Unknown Source)
        at com.google.android.gms.maps.internal.x.onTransact(SourceFile:129)
        at android.os.Binder.transact(Binder.java:310)
        at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onDestroyView(Unknown Source)
        at com.google.android.gms.maps.MapFragment$zza.onDestroyView(Unknown Source)
        at com.google.android.gms.dynamic.zza.onDestroyView(Unknown Source)
        at com.google.android.gms.maps.MapFragment.onDestroyView(Unknown Source)
        at android.app.Fragment.performDestroyView(Fragment.java:1893)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:949)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1039)
        at android.app.FragmentManagerImpl.dispatchDestroy(FragmentManager.java:1868)
        at android.app.Activity.performDestroy(Activity.java:5290)
        at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1112)
        at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3611)

这是我的活动代码：

public class InfoActivity extends AppCompatActivity {

Toolbar actionBarToolBar;

CityMapFragment cityMapFragment;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_news_info);
    actionBarToolBar = (Toolbar)findViewById(R.id.event_info_toolbar);
    setSupportActionBar(actionBarToolBar);
    actionBarToolBar.setNavigationIcon(R.mipmap.ic_action_direction);
    actionBarToolBar.setNavigationOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });

    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    cityMapFragment = CityMapFragment.getNewInstance(savedInstanceState);
    ft.add(R.id.layoutMapEvent, cityMapFragment);
    ft.commit();
}

@Override
public void onBackPressed() {
    super.onBackPressed();
    }

@Override
protected void onPause() {
    super.onPause();
    cityMapFragment.onPause();
    }

@Override
protected void onStop() {
    super.onStop();
   cityMapFragment.onStop();
    }


@Override
protected void onResume() {
    super.onResume();
    cityMapFragment.onResume();
    }

@Override
protected void onDestroy() {
    super.onDestroy();
    cityMapFragment.onDestroy();
    }
}

这里是我的CityMapFragment代码：

public class CityMapFragment extends Fragment实现OnMapReadyCallback {

public static CityMapFragment getNewInstance(Bundle savedInstanceState)
{
    CityMapFragment cityMapFragment = new CityMapFragment();
    cityMapFragment.onCreate(savedInstanceState);
    return cityMapFragment;
}

public GoogleMap googleMap;
public MapFragment mapFragment;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.map_fragment_layout, container, false);
    mapInit(savedInstanceState);
    return v;
}

@Override
public void onMapReady(GoogleMap _googleMap) {
    this.googleMap = _googleMap;
    googleMap.setMyLocationEnabled(true);
    googleMap.getUiSettings().setMyLocationButtonEnabled(true);
    googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
        @Override
        public void onMapClick(LatLng latLng) {
            Toast.makeText(getActivity(), "TAP", Toast.LENGTH_SHORT).show();
        }
    });
}

private void mapInit(Bundle savedInstanceState)
{
    if(googleMap == null)
    {
        switch (GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity()))
        {
            case ConnectionResult.SUCCESS:
                MapsInitializer.initialize(getActivity());
                mapFragment = (MapFragment)getFragmentManager().findFragmentById(R.id.mapFragmentID);
                mapFragment.onCreate(savedInstanceState);
                if(mapFragment != null)
                {
                    mapFragment.getMapAsync(this);
                }

                Toast.makeText(getActivity(), "SUCCES", Toast.LENGTH_SHORT).show();
                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();
        }
    }
    /*if(googleMap != null)
    {
        mapSetting();
    }*/
}

public void setMarkerAndFocus(LatLng latlg, String text) {
    googleMap.addMarker(new MarkerOptions().position(latlg).title(text));
    focusLocation(latlg);
}

public void setMarker(LatLng latlg, String text)
{
}

public void focusLocation(LatLng latlg)
{
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latlg, 15);
    googleMap.animateCamera(cameraUpdate);
}
@Override
public void onResume() {
    super.onResume();
    mapFragment.onResume();
}

@Override
public void onPause() {
    super.onPause();
    mapFragment.onPause();
}

@Override
public void onStop() {
    super.onStop();
    mapFragment.onStop();
}

@Override
public void onLowMemory() {
    super.onLowMemory();
    mapFragment.onLowMemory();
}

@Override
public void onDestroyView() {
    super.onDestroyView();
}

@Override
public void onDestroy() {
    super.onDestroy();
    mapFragment.onDestroy();
    }
}

我认为问题在于

ft.add(R.id.layoutMapEvent, cityMapFragment);
ft.commit();

因为当我删除此代码时，没有抛出java.lang.NullPointerException。但我想在我的Activity上显示地图，我无法从我的Activity中删除它。我需要2天时间，但我无法正确解决。

非常感谢你帮助!!!!

Answer 1

尝试从CityMapFragment中删除onDestroyView()方法。当您的Activity被销毁时，您的Fragment也会被自动销毁。因此，没有必要。

当Activity中的onBackPressed有一个MapFragment

1 个答案: