SupportMapFragment.getMap() przy odwołaniu do obiektu o wartości zerowej

Question

Po prawie wszystkich próbach nie mogę wykonać mapowania bez wyciągnięcia referencji o wartości zerowej. Próbuję nadpisać fragment mapy google do fragmentu, jednak za każdym razem, gdy to robię, zawsze przechowuję obiekt zerowy getmap.

Oto mój kod

jestem zdesperowany za wszelką pomoc w tym momencie, próbowałem prawie wszystko.

Błąd

java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference 
      at com.gnumbu.errolgreen.importedapplication.ViewMapFragment.onViewCreated(ViewMapFragment.java:122) 
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:971) 
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136) 
      at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739) 
      at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1499) 
      at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:488) 
      at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:1073) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:919) 
      at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:580) 
      at android.view.Choreographer.doFrame(Choreographer.java:550) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:135) 
      at android.app.ActivityThread.main(ActivityThread.java:5221) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 

klasa Fragment java

public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     if (container == null) { 
      return null; 
     } 
     view = (RelativeLayout) inflater.inflate(R.layout.fragmentmenu_layout, container, false); 
     // Passing harcoded values for latitude & longitude. Please change as per your need. This is just used to drop a Marker on the Map 
     latitude = 26.78; 
     longitude = 72.56; 

     ; // For setting up the MapFragment 

     return view; 
    } 

    /***** Sets up the map if it is possible to do so *****/ 
    public static void setUpMapIfNeeded() { 
     // Do a null check to confirm that we have not already instantiated the map. 
     if (mMap == null) { 
      // Try to obtain the map from the SupportMapFragment. 
      mMap = ((SupportMapFragment) SectionsPagerAdapter.fragmentManager 
        .findFragmentById(R.id.mapView)).getMap(); 
      // Check if we were successful in obtaining the map. 
      if (mMap != null) 
       setUpMap(); 
     } 
    } 

    /** 
    * This is where we can add markers or lines, add listeners or move the 
    * camera. 
    * <p> 
    * This should only be called once and when we are sure that {@link #mMap} 
    * is not null. 
    */ 
    private static void setUpMap() { 
     // For showing a move to my loction button 
     mMap.setMyLocationEnabled(true); 
     // For dropping a marker at a point on the Map 
     mMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("My Home").snippet("Home Address")); 
     // For zooming automatically to the Dropped PIN Location 
     mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, 
       longitude), 12.0f)); 

    } 

    @Override 
    public void onViewCreated(View view, Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     if (mMap != null) 
      setUpMap(); 

     if (mMap == null) { 
      // Try to obtain the map from the SupportMapFragment. 
      mMap = ((SupportMapFragment) MainActivity.fragmentManager 
        .findFragmentById(R.id.mapView)).getMap(); // getMap is deprecated 
      // Check if we were successful in obtaining the map. 
      if (mMap != null) 
       setUpMap(); 
      getAllFeaturedItems(); 
      captureMapScreen(); 
     } 
    } 

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

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

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

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

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

    /**** The mapfragment's id must be removed from the FragmentManager 
    **** or else if the same it is passed on the next time then 
    **** app will crash ****/ 
    @Override 
    public void onDestroyView() { 
     super.onDestroyView(); 
     if (mMap != null) { 
      MainActivity.fragmentManager.beginTransaction() 
        .remove(MainActivity.fragmentManager.findFragmentById(R.id.mapView)).commit(); 
      mMap = null; 
     } 
    } 

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

fragmentmenu_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:translationZ="5dp" 
> 


    <ListView 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:id="@+id/listViewMenu" 
     android:layout_gravity="center_horizontal" 
     android:dividerHeight="1sp" 
     android:translationZ="5dp" 
     android:divider="@color/background_default" 
     android:background="@color/background_white" 
     android:clickable="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_below="@+id/screenShotMapView" /> 

    <ImageView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/screenShotMapView" 
     android:layout_alignParentTop="true" 
     android:maxWidth="50dp" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true" 
     android:adjustViewBounds="true" 
     android:translationZ="5dp" 
    /> 



     <fragment 
      class="com.google.android.gms.maps.MapFragment" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:id="@+id/mapView" 
      android:layout_alignParentTop="true" 
      android:layout_alignParentRight="true" 
      android:layout_alignParentEnd="true" 
      android:layout_alignParentLeft="true" 
      android:layout_alignParentStart="true" 
      android:adjustViewBounds="true" 
      android:longClickable="false" 
      android:visibility="visible" 
      android:maxHeight="50dp" 
      android:maxWidth="50dp" 
     /> 






</RelativeLayout> 

MainActivity.java

public static FragmentManager fragmentManager; 



    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // setTheme(R.style.ActionBarTheme); 
     super.onCreate(savedInstanceState); 

     setContentView(R.layout.activity_main); 

     // initialising the object of the FragmentManager. Here I'm passing getSupportFragmentManager(). You can pass getFragmentManager() if you are coding for Android 3.0 or above. 


    // final ActionBar actionBar = getSupportActionBar(); 
     buildGoogleApiClient(); 

//  actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
//  actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 

     mImageBitmap = null; 

     // Create the adapter that will return a fragment for each section/page 
     mSectionsPagerAdapter = new SectionsPagerAdapter(
       this.getBaseContext(), getSupportFragmentManager()); 
     fragmentManager = getSupportFragmentManager(); 
     // Set up the ViewPager with the sections adapter. 
     mViewPager = (ViewPager) findViewById(R.id.pager); 

     mViewPager.setAdapter(mSectionsPagerAdapter); 

     mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 
      @Override 
      public void onPageSelected(int position) { 
     //   actionBar.setSelectedNavigationItem(position); 
      } 
     }); 

     // For each of the sections in the app, add a tab to the action bar. 
     /* 
     for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) { 
      // Create a tab with text corresponding to the page title defined by 
      // the adapter. Also specify this Activity object, which implements 
      // the TabListener interface, as the callback (listener) for when 
      // this tab is selected. 

        if (i == 0) { 
         actionBar.addTab(
           actionBar.newTab() 

             .setIcon(R.drawable.ic_action_view_as_list) 
             // .setText(mSectionsPagerAdapter.getPageTitle(i)) 
             .setTabListener(this) 
         ); 
        } 
        if (i == 1) { 
         actionBar.addTab(
            actionBar.newTab() 

           .setIcon(R.drawable.ic_action_web_site_dark) 
           // .setText(mSectionsPagerAdapter.getPageTitle(i)) 
           .setTabListener(this) 
       ); 
      } 
     } 
     */ 
     mAlbumStorageDirFactory = new BaseAlbumDirFactory(); 


     Intent intent = new Intent(this, SplashScreen.class); 
     startActivity(intent); 

} 

Answer 1

Niezbyt pewny dlaczego ja downvoted tyle na ten temat, jednak mam rozwiązać ten problem.

Linia ta

mMap = ((SupportMapFragment) MainActivity.fragmentManager 
        .findFragmentById(R.id.mapView)).getMap(); 

musiała zostać zmieniona na

mMap = ((SupportMapFragment) getChildFragmentManager() 
       .findFragmentById(R.id.mapView)).getMap(); 

Answer 2

Problemem jest to, że starają się dostać mapę z SupportMapFragment ale używasz innego rodzaju MapFragment który jest wyraźnie widoczny w xml

class="com.google.android.gms.maps.MapFragment" 

powinno być

class="com.google.android.gms.maps.SupportMapFragment" 

Aby umożliwić initilized typ SupportMapFragment z kodu

Answer 3

Zmieniłem getMap() do getMapAsync(OnMapReadyCallback) i to działało.

Źródło:SupportMapFragment

Answer 4

android: name = powinna być zmiana "com.google.android.gms.maps.SupportMapFragment" czyli

Od

<fragment android:name="com.google.android.gms.maps.MapFragment" 
android:layout_width="match_parent"  
android:layout_height="match_parent"/> 

do

<fragment android:name="com.google.android.gms.maps.SupportMapFragment" 
android:layout_width="match_parent" 
android:layout_height="match_parent"/>