Фрагмент сбоев при смене навигации

Question

У меня есть ящик для навигации, где есть несколько вариантов, таких как выставка, художник и галерея. Когда я нажимаю элемент в представлении контента на моей выставке, он работает. Затем, если я попытаюсь перейти к другому элементу элемента навигации, например Artist или Gallery, после предварительного просмотра элемента в отдельной работе с фрагментом, произойдет сбой всего приложения. Может ли кто-нибудь помочь?

Код ..

private class LoadViewTask extends AsyncTask<Void, Integer, Void> { 
    Activity mContex; 
    GridView listView; 

    public LoadViewTask(Activity mContext, GridView grid_view) { 
     ....... 
    } 

    @Override 
    protected void onPreExecute() { 
     .... 
    } 

    @Override 
    protected Void doInBackground(Void... params) { 
     ........... 

    } 

    @Override 
    protected void onPostExecute(Void result) { 
     progressDialog.dismiss(); 

     if(getActivity()!=null){ 
     loadListing(); 
     } 

    } 

    private void loadListing() { 
     ChannelAppProductsArrayAdapter adapter = new ChannelAppProductsArrayAdapter(
       mContex, R.layout.itemlisting, productList, imageLoader); 

     listView.setAdapter(adapter); 

     //EDITED VERSION TO INITIATE SLIDER DRAWER 
     mDrawer = (DrawerLayout) getActivity().findViewById(R.id.drawer_layout); 
     //prevent user from manually opening the drawer 
     mDrawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED); 
     //Allow ScrollView at the preview-layout 
     ScrollView SV= (ScrollView) getActivity().findViewById(R.id.scrollView_Preview_Layout); 
     SV.scrollTo(0, 0); 
     SV.fullScroll(ScrollView.FOCUS_UP); 
     //END OF EDITED VERSION TO INITIATE SLIDER DRAWER 

     //listView.setOnClickListener() 


     listView.setOnItemClickListener(new OnItemClickListener() { 
      public void onItemClick(AdapterView<?> parent, View view, 
        int position, long id) { 

       /*String text = "Item click... should be implemented @ position: " 
         + position; 
       Toast.makeText(mContex, text, Toast.LENGTH_LONG).show();*/ 
       Product product = productList.get(position); 
       String productID = product.getId(); 


       String productDesc = product.getName(); 
       TextView ProductSummary; 
       String productName=product.getDescription(); 
       TextView ProductName; 
       ImageView productImage; 
       imageLargename=productList.get(position).getLarge_image(); 

       //EDITED VERSION TO SHOW RIGHT DRAWER-18/11/2014 
       mDrawerToggle = new CustomActionBarDrawerToggle(getActivity(), mDrawer); 
       mDrawer.openDrawer(GravityCompat.END); 
       mDrawer.setDrawerListener(mDrawerToggle); 
       getActivity().getActionBar().setHomeButtonEnabled(true); // Prevents user from opening the drawer using the app icon 

       Log.i("View onItemClick: ArtistProductDetailsFragment", "toggleRightDrawer()"+ productDesc); 
       //END OF EDITED VERSION TO SHOW RIGHT DRAWER-18/11/2014 

       //EDITED VERSION TO DISPLAY VIEW FOR SELECTED FRAGMENT ITEM-19/11/2014 
       View RDrawerView = mDrawer.findViewById(R.id.preview_layout); 

       //To set TextView of Product Name 
       ProductSummary = (TextView) RDrawerView.findViewById(R.id.productsummary); 
       ProductSummary.setText(productDesc); 

       //To set TextView of product description 
       ProductName= (TextView) RDrawerView.findViewById(R.id.productdesc); 
       ProductName.setText(productName); 

       //To get product Image from array 
       productImage =(ImageView) RDrawerView.findViewById(R.id.productimage); 
       String imgFilePath = url + imageLargename; 
       imageLoader.displayImage(imgFilePath, productImage, options); 


       productImage.setOnClickListener(new OnClickListener(){ 

        @Override 
        public void onClick(View v) { 
         // TODO Auto-generated method stub 
         Toast.makeText(mContex, 
           "Pinch & Zoom To See Large Photo.", 
           Toast.LENGTH_SHORT).show(); 
         String imgFilePath = url + imageLargename; 
         Intent intent = new Intent(
           mContex.getApplicationContext(), 
           FullScreenViewActivity.class); 
         intent.putExtra("path", imgFilePath); 
         startActivity(intent); 
        } 

       }); 
       //END OF EDITED VERSION TO DISPLAY VIEW FOR SELECTED FRAGMENT ITEM-19/11/2014 

      } 
     }); 

    } 

    //EDITED VERSION FOR CUSTOMACTIONBARDRAWERTOGGLE 
    private class CustomActionBarDrawerToggle extends ActionBarDrawerToggle { 

     public CustomActionBarDrawerToggle(Activity mActivity, 
       DrawerLayout mDrawerLayout) { 
      super(mActivity, mDrawerLayout, R.drawable.ic_drawer, 
        R.string.ns_menu_open, R.string.ns_menu_close); 
     } 

     @Override 
     public void onDrawerClosed(View view) { 
      getActivity().getActionBar().setTitle(getActivity().getString(R.string.ns_menu_close)); 
      getActivity().invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 

     @Override 
     public void onDrawerOpened(View drawerView) { 
      getActivity().getActionBar().setTitle(getActivity().getString(R.string.ns_menu_open)); 
      getActivity().invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 
    } 
    //END OF EDITED VERSION FOR CUSTOMACTIONBARDRAWERTOGGLE 

} 

Error Log ..

11-26 10:47:50.719: E/AndroidRuntime(19168): FATAL EXCEPTION: main 
11-26 10:47:50.719: E/AndroidRuntime(19168): java.lang.NullPointerException 
11-26 10:47:50.719: E/AndroidRuntime(19168): at com.dapoaugury.channelappdemo.fragment.ChannelAppProductFragment$LoadViewTask$CustomActionBarDrawerToggle.onDrawerClosed(ChannelAppProductFragment.java:332) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.support.v4.widget.DrawerLayout.dispatchOnDrawerClosed(DrawerLayout.java:477) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.support.v4.widget.DrawerLayout.updateDrawerState(DrawerLayout.java:457) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.support.v4.widget.DrawerLayout$ViewDragCallback.onViewDragStateChanged(DrawerLayout.java:1355) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.support.v4.widget.ViewDragHelper.setDragState(ViewDragHelper.java:866) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.support.v4.widget.ViewDragHelper$2.run(ViewDragHelper.java:335) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.os.Handler.handleCallback(Handler.java:725) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.os.Handler.dispatchMessage(Handler.java:92) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.os.Looper.loop(Looper.java:137) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at android.app.ActivityThread.main(ActivityThread.java:5039) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at java.lang.reflect.Method.invokeNative(Native Method) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at java.lang.reflect.Method.invoke(Method.java:511) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
11-26 10:47:50.719: E/AndroidRuntime(19168): at dalvik.system.NativeStart.main(Native Method) 

EDIT 1:

я решил свой собственный вопрос. Благодарю.

То есть полностью удалить весь метод для private class CustomActionBarDrawerToggle extends ActionBarDrawerToggle. Я понял, что он не применим для второго ящика, поскольку он не вызывает панель действия для любой функции выдвижного ящика.

Answer 1

То есть, чтобы полностью удалить весь метод для частного класса CustomActionBarDrawerToggle extends ActionBarDrawerToggle