Warum PagerAdapter innerhalb des Fragments zeigt nur die erste Ansicht?

Question

Dies ist mein PagerAdapter.

public class SlideAdapter extends PagerAdapter{ 
    private List<ImageView> views; 

    public SlideAdapter (List<ImageView> views){ 
     this.views=views; 
    } 

    @Override 
    public void destroyItem(View container, int position, Object object) { 
     ((ViewPager) container).removeView(views.get(position)); 
    } 

    @Override 
    public int getCount() { 
     return views.size(); 
    } 

    @Override 
    public boolean isViewFromObject(View view, Object object) { 
     return view==object; 
    } 

    @Override 
    public Object instantiateItem(View container, int position) { 
     ((ViewPager) container).addView(views.get(position)); 
     return views.get(position); 
    } 

} 

Das ist mein Fragment.

public class sportfragment extends Fragment { 

    private ViewPager slideviewpager; 
    private Boolean isContinue=true; 
    private AtomicInteger what=new AtomicInteger (0); 
    private ImageView[] indiimageview; 
    private List<ImageView> pics; 

    private static final String ARG_PARAM1 = "param1"; 
    private static final String ARG_PARAM2 = "param2"; 


    private String mParam1; 
    private String mParam2; 

    private OnFragmentInteractionListener mListener; 

    public sportfragment() { 

    } 


    public static sportfragment newInstance(String param1, String param2) { 
     sportfragment fragment = new sportfragment(); 
     Bundle args = new Bundle(); 
     args.putString(ARG_PARAM1, param1); 
     args.putString(ARG_PARAM2, param2); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     if (getArguments() != null) { 
      mParam1 = getArguments().getString(ARG_PARAM1); 
      mParam2 = getArguments().getString(ARG_PARAM2); 
     } 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 

     View view=inflater.inflate(R.layout.fragment_sportfragment, container, false); 

     slideviewpager=(ViewPager) view.findViewById(R.id.slideviewpager); 
     ViewGroup indicatorgroup=(ViewGroup) view.findViewById(R.id.indicatorgroup); 

     pics=new ArrayList<ImageView>(); 

     ImageView slide1=new ImageView(view.getContext()); 
     slide1.setBackgroundResource(R.drawable.slide1); 
     pics.add(slide1); 

     ImageView slide2=new ImageView(view.getContext()); 
     slide1.setBackgroundResource(R.drawable.slide2); 
     pics.add(slide2); 

     ImageView slide3=new ImageView(view.getContext()); 
     slide1.setBackgroundResource(R.drawable.slide3); 
     pics.add(slide3); 

     ImageView slide4=new ImageView(view.getContext()); 
     slide1.setBackgroundResource(R.drawable.slide4); 
     pics.add(slide4); 

     indiimageview=new ImageView[pics.size()]; 

     for (int i=0;i<pics.size();i++) { 
      ImageView buff=new ImageView(view.getContext()); 
      buff.setLayoutParams(new LinearLayout.LayoutParams(20,20)); 
      buff.setPadding(5,5,5,5); 
      indiimageview[i]=buff; 
      if (i==0) { 
       indiimageview[i].setBackgroundResource(R.drawable.focus); 
      }else { 
       indiimageview[i].setBackgroundResource(R.drawable.blur); 
      } 
      indicatorgroup.addView(indiimageview[i]); 
     } 

     slideviewpager.setAdapter(new SlideAdapter(pics)); 
     slideviewpager.setOnPageChangeListener(new GuidePageChangeListener()); 

     return view; 
    } 


    public void onButtonPressed(Uri uri) { 
     if (mListener != null) { 
      mListener.onFragmentInteraction(uri); 
     } 
    } 


    @Override 
    public void onAttach(Context context) { 
     super.onAttach(context); 

    } 

    @Override 
    public void onDetach() { 
     super.onDetach(); 
     mListener = null; 
    } 


    public interface OnFragmentInteractionListener { 
     // TODO: Update argument type and name 
     void onFragmentInteraction(Uri uri); 
    } 

    private final class GuidePageChangeListener implements ViewPager.OnPageChangeListener{ 

     @Override 
     public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { 

     } 

     @Override 
     public void onPageSelected(int position) { 

      for (int i=0;i<indiimageview.length;i++) { 

       if (i==position) { 
       //4 points change with viewpager 
        indiimageview[i].setBackgroundResource(R.drawable.focus); 
       } else { 
        indiimageview[i].setBackgroundResource(R.drawable.blur); 
       } 
      } 
     } 

     @Override 
     public void onPageScrollStateChanged(int state) { 

     } 
    } 
} 

Erste Seite ist das Bild. Aber andere 3 ist leer. Gibt es eine Möglichkeit, dies zu lösen?

Answer 1

ViewPagers sind für die Verwendung mit Fragmenten gedacht, nicht für Ansichten. Das bedeutet, dass Sie Ihre ImageViews eher als Fragmente als als reine alte Ansichten verpacken sollten.

Betrachten Sie das folgende Beispiel:

MyImageView.java

public class MyImageFragment extends Fragment { 

    private ImageView mImageView; 
    private int resourceId; 

    public static MyImageFragment newInstance(int resourceId) { 
     MyImageFragment fragment = new MyImageFragment(); 

     Bundle args = new Bundle(); 
     args.putInt("resource_id", resourceId); 
     fragment.setArguments(args); 

     return fragment; 
    } 

    @Override 
    public void onCreate(final Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     final Bundle args = getArguments(); 
     if (args != null && !loadedFromArgs) { 
      url = (String)args.getSerializable("url"); 
      resourceId = args.getInt("in_list", -1); 
      loadedFromArgs = true; 
     } 

    } 

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

     mImageView = (ImageView) rootView.findViewById(R.id.image); 
     mImageView.setBackgroundDrawable(getResources().getDrawable(resourceId)) 
     return rootView; 
    } 
} 

fragment_my_image.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="wrap_content"> 

    <ImageView 
     android:id="@+id/image" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:scaleType="fitCenter" 
     android:adjustViewBounds="true" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true"/> 

</RelativeLayout> 

nun statt einer Liste von ImageViews, haben Sie eine Liste von MyImageFragment s, auf die Ihr PagerAdapter zeigen wird.