Question

我有一个简单的FragmentPagerAdapter：

public class SectionsPagerAdapter extends FragmentPagerAdapter {

public SectionsPagerAdapter(FragmentManager fm) {
    pagerAdapterList = new ArrayList<>();
    super(fm);
}

@Override
public Fragment getItem(int position) {
    PagerAdapter fragment;
    if (position > pagerAdapterList.size() - 1) {
                fragment = new PagerAdapter(followRequests.get(position));
                pagerAdapterList.add(fragment);

            } else
                return pagerAdapterList.get(position);

    return fragment;
}

        public int removeView (ViewPager pager, int position)
    {
        pager.setAdapter (null);
        pagerAdapterList.remove (position);
        data.remove (position);
        pager.setAdapter (this);

        return position;
    }

        @Override
    public Object instantiateItem(ViewGroup container, int position) {
        getItem(position);
        return super.instantiateItem(container, position);
    }

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

}

和PagerAdapter类：

public class PagerAdapter extends Fragment {

Data data;
private View overlayView;

public PagerAdapter() {
}

public PagerAdapter(Data data) {
    this.data= data;
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.notification_header_fragment_pager, container, false);
    TextView id_txtView = (TextView) 
    overlayView = (View) rootView.findViewById(R.id.viewOverlay);

    //bind some data for example id_txtView.setText(data.getText());

    return rootView;
}

public void showOverlayView() {
    if(overlayView != null)
    overlayView.setVisibility(View.VISIBLE);
}
}

首先我打电话

removeView（mViewPager，position）;

然后我获得新数据，然后调用

adapter.notifyDataSetChanged（）;

一切正常，我可以在PagerAdapter中绑定新数据并在View Pager上显示。

但是当我打电话时

（（PagerAdapter）adapter.getItem（mViewPager.getCurrentItem（）））。showOverlayView（）;

我得到当前片段而没有任何对其ui组件的引用（如overlayView），它们都是null !!

我错了什么？请帮帮我，谢谢。

FragmentPagerAdapter中碎片的参考丢失

0 个答案: