从 RecyclerView 中消失的数据

Question

我用包含 ViewPager 的片段制作了一个应用程序。在那个 ViewPager 中，我正在使用 RecyclerView 显示列表。当我启动应用程序时，一切都很好。但是，当我滑动几个选项卡并且未显示返回列表时。不知道怎么回事...

在 ViewPager 中显示的片段

public class GradesFragmentPage extends Fragment {
    View view;
    List<Grade> gradeList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.grades_page_fragment, container, false);
    }

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

        BetterRecyclerView betterRecyclerView = (BetterRecyclerView) getActivity().findViewById(R.id.gradesRecycler);
        betterRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        this.view = view;

        if(getArguments() != null) {
            gradeList = getArguments().getParcelableArrayList("grades");

            BetterRecyclerView betterRecyclerView = (BetterRecyclerView) view.findViewById(R.id.gradesRecycler);
            betterRecyclerView.setAdapter(new GradesAdapter(getActivity(), gradeList));
        }
    }
}

BetterRecyclerView

public class BetterRecyclerView extends RecyclerView {
    public BetterRecyclerView(Context context) {
        super(context);
    }

    public BetterRecyclerView(Context context, AttributeSet attrs) {
        super(context,attrs);

        setLayoutManager(new LayoutManager() {
            @Override
            public LayoutParams generateDefaultLayoutParams() {
                return null;
            }
        });
    }

    public BetterRecyclerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    //we need this protected method for scroll detection
    public int getVerticalScrollOffset() {
        return computeVerticalScrollOffset();
    }
}

Answer 1

ViewPager 本身有一个方法 setOffscreenPageLimit 允许您指定适配器保留的页面数。所以你在远处的碎片会被销毁。

首先查看您的代码，我没有看到您在片段 onDestroy() 中执行任何内存释放措施。片段本身被销毁和 gc'ed 的事实并不意味着您分配的所有资源也被删除。

viewPager.setOffscreenPageLimit(10);

从 RecyclerView 中消失的数据

Disappearing data from RecyclerView

java

android

android-fragments

android-viewpager

android-recyclerview