Map fragment stürzt bei resume ab

Question

Ich versuche, ein Kartenansichtsfragment innerhalb eines Tabs anzuzeigen, aber aus irgendeinem Grund, wenn ich den Kippschalter wechsle und zu einem anderen Tab gehe, stürzt die App ab, wenn ich zu dem Tab mit der Map zurückkehre . Ich schaute auf den Code onResume(), aber ich bin mir nicht sicher, was innerhalb der Klasse geändert werden muss.

public class FragmentCentralParkLocation extends android.support.v4.app.Fragment implements OnMapReadyCallback { 

    public FragmentCentralParkLocation() { 
     // Required empty constructor 
    } 

    GoogleMap mGoogleMap; 
    MapView mMapView; 

    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     View v = inflater.inflate(R.layout.fragment_centralpark_location, container, false); 

     mMapView = (MapView) v.findViewById(R.id.map_centralpark); 
     mMapView.onCreate(savedInstanceState); 
     mMapView.getMapAsync(this); //this is important 

     SwitchCompat swt = (SwitchCompat) v.findViewById(R.id.switch_map_centralpark); 
     swt.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 
      @Override 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
       if(isChecked){ 
        boolean success = mGoogleMap.setMapStyle(new MapStyleOptions(getResources() 
          .getString(R.string.style_json)));  
       }else{ 
        boolean success = mGoogleMap.setMapStyle(null); 
       } 
      } 
     }); 



     return v; 
    } 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 
     mGoogleMap = googleMap; 
     mGoogleMap.getUiSettings().setZoomControlsEnabled(true); 
     mGoogleMap.setBuildingsEnabled(true); 
     mGoogleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); 

     // Add markers and move the camera 
     LatLng knt_location = new LatLng(40.782893, -73.965422); 
     mGoogleMap.addMarker(new MarkerOptions() 
       .position(knt_location) 
     ); 


     // Updates the location and zoom level of the MapView 
     CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(40.782893, -73.965422), 18); 
     mGoogleMap.animateCamera(cameraUpdate); 
    } 

    @Override 
    public void onResume() { 
     super.onResume(); 
     mMapView.onResume(); 
    } 

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

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

    @Override 
    public void onSaveInstanceState(Bundle outState) { 
     super.onSaveInstanceState(outState); 
     mMapView.onSaveInstanceState(outState); 
    } 

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

Stufe 1

Stufe 2

Stufe 3

Logcat

03-12 16:45:24.965 2328-2328/com.ustravel.parks E/AndroidRuntime: FATAL EXCEPTION: main 
                        Process: com.ustravel.parks, PID: 2328 
                        java.lang.NullPointerException 
                         at com.ustravel.parks.FragmentCentralParkLocation $1.onCheckedChanged(FragmentCentralParkLocation.java:49) 
                         at android.widget.CompoundButton.setChecked(CompoundButton.java:127) 
                         at android.support.v7.widget.SwitchCompat.setChecked(SwitchCompat.java:1062) 
                         at android.widget.CompoundButton.onRestoreInstanceState(CompoundButton.java:381) 
                         at android.view.View.dispatchRestoreInstanceState(View.java:12799) 
                         at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2643) 
                         at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2643) 
                         at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2643) 
                         at android.view.View.restoreHierarchyState(View.java:12777) 
                         at android.support.v4.app.Fragment.restoreViewState(Fragment.java:475) 
                         at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1329) 
                         at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528) 
                         at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595) 
                         at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:757) 
                         at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2355) 
                         at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2146) 
                         at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2098) 
                         at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1979) 
                         at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:626) 
                         at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:166) 
                         at android.support.v4.view.ViewPager.populate(ViewPager.java:1268) 
                         at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:668) 
                         at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:630) 
                         at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:611) 

onResume Karte Ergebnis

Answer 1

Ich glaube, Sie versuchen, den Zustand Ihrer SwitchCompat vor Ihrerwiederherstellenist bereit und initialisiert. Hier habe ich Ihren Code ein wenig verändert:

public class FragmentCentralParkLocation extends android.support.v4.app.Fragment implements OnMapReadyCallback { 

    public FragmentCentralParkLocation() { 
     // Required empty constructor 
    } 

    GoogleMap mGoogleMap; 
    MapView mMapView; 
    SwitchCompat swt; 

    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     View v = inflater.inflate(R.layout.fragment_centralpark_location, container, false); 

     mMapView = (MapView) v.findViewById(R.id.map_centralpark); 
     mMapView.onCreate(savedInstanceState); 
     mMapView.getMapAsync(this); //this is important 

     swt = (SwitchCompat) v.findViewById(R.id.switch_map_centralpark); 

     return v; 
    } 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 
     mGoogleMap = googleMap; 
     mGoogleMap.getUiSettings().setZoomControlsEnabled(true); 
     mGoogleMap.setBuildingsEnabled(true); 
     mGoogleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); 

     swt.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 
      @Override 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
       initMap(isChecked); 
      } 
     }); 

     initMap(swt.isChecked()); 

     // Add markers and move the camera 
     LatLng knt_location = new LatLng(40.782893, -73.965422); 
     mGoogleMap.addMarker(new MarkerOptions() 
       .position(knt_location) 
     ); 


     // Updates the location and zoom level of the MapView 
     CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(40.782893, -73.965422), 18); 
     mGoogleMap.animateCamera(cameraUpdate); 
    } 

    @Override 
    public void onResume() { 
     super.onResume(); 
     mMapView.onResume(); 
    } 

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

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

    @Override 
    public void onSaveInstanceState(Bundle outState) { 
     super.onSaveInstanceState(outState); 
     mMapView.onSaveInstanceState(outState); 
    } 

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

    private void initMap(boolean isChecked){ 
      if(isChecked){ 
        mGoogleMap.setMapStyle(new MapStyleOptions(getResources() 
          .getString(R.string.style_json)));  
       }else{ 
        mGoogleMap.setMapStyle(null); 
       } 
    } 
} 

Ich hoffe, das wird Ihnen helfen.

bearbeiten: Wenn Sie noch Absturz auftreten, können Sie versuchen onCheckedChangeListener von SwitchCompat in onStop oder onDestroy zu entfernen, indem Sie den folgenden Code versuchen:

swt.setonCheckedChangeListener(null);