旋转后recyclerview行中的图像消失

Question

在我的 recyclerview 中，我根据某些条件设置了一个图像（在 recyclerview 行中）可见或不可见。

但是，在我旋转屏幕后，图像消失了，如何在 在旋转屏幕后在回收站视图中保持图像在 其位置可见？

感谢您的帮助，祝您节日快乐；）

我正在使用 SimpleAdapter 的实现。

public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.SimpleViewHolder> implements FollowRedirectsCallback {

public static class SimpleViewHolder extends RecyclerView.ViewHolder {
        ...
        public final View icCancel;

        public SimpleViewHolder(View view) {
            super(view);
            ...
            icCancel = view.findViewById(R.id.icCancel);
        }
    }

    public SimpleAdapter(Context context, String[] data, long userId, int dlTypeValue) {
        mContext = context;
        userID = userId;
        DLTypeValue = dlTypeValue;
        if (data != null)
            mData = new ArrayList<String>(Arrays.asList(data));
        else mData = new ArrayList<String>();
    }

    public SimpleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        final View view = LayoutInflater.from(mContext).inflate(R.layout.simple_item, parent, false);
        return new SimpleViewHolder(view);
    }

@Override
    public void onBindViewHolder(final SimpleViewHolder holder, final int position) {
    ...
    // How to keep this image visible after rotation of the screen?
    if (somecondition) {
      holder.icCancel.setVisibility(View.VISIBLE);
    }
}

编辑：我在对应的活动中初始化我的适配器：

public class DownloadsActivity extends BaseActivity {

    RecyclerView recyclerView;
    Parcelable state;
    SimpleAdapter mAdapter;
    SimpleSectionedRecyclerViewAdapter mSectionedAdapter;
    SimpleSectionedRecyclerViewAdapter.Section[] dummy;

@AfterViews
    public void init() {
    recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

        //setLayout Manager
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setHasFixedSize(true);

        dummy = new SimpleSectionedRecyclerViewAdapter.Section[sections.size()];
        mSectionedAdapter = new
                SimpleSectionedRecyclerViewAdapter(this, R.layout.section, R.id.section_text, mAdapter);
        mSectionedAdapter.setSections(sections.toArray(dummy));


        //Apply this adapter to the RecyclerView
        recyclerView.setAdapter(mSectionedAdapter);
   }

@Override
protected void onPause() {
    super.onPause();
    // save RecyclerView state
    state = recyclerView.getLayoutManager().onSaveInstanceState();
}

@Override
protected void onResume() {
    super.onResume();
    if (inProgress) {
        progresstxt.setVisibility(View.VISIBLE);
        downloadprogress.setVisibility(View.VISIBLE);
    }

    // restore RecyclerView state
    recyclerView.getLayoutManager().onRestoreInstanceState(state);
}

}

Answer 1

您可以将图像的可见性状态保存在ArrayList 中，然后将其作为参数传递给适配器。在您的 Activity 中，使用 onSaveInstanceState 保存 ArrayList。

public class YourActivity extends BaseActivity {
    /* some codes */

    // possible values are: VISIBLE, INVISIBLE, or GONE
    private ArrayList<Integer> imagesState = new ArrayList<>();

    /* some codes */

    @Override
    protected void onCreate(Bundle savedInstanceState) {
       if(savedInstanceState != null) {
           imagesState = savedInstanceState.getIntegerArrayList("key");
       }

       // Pass the imagesState to the adapter as a parameter here
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putIntegerArrayList("key", imagesState);
    }

    /* some codes */
}

然后在您的适配器中：

public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.SimpleViewHolder> implements FollowRedirectsCallback {

    /* some codes */

    public SimpleAdapter(Context context, String[] data, long userId, int dlTypeValue, ArrayList<Integer> imagesState) {
        /* some codes */
        this.imagesState = imagesState;
    }

    @Override
    public void onBindViewHolder(SimpleViewHolder holder, int position) {
        /* some codes */

        if (imagesState.get(position) == View.VISIBLE)
            holder.icCancel.setVisibility(View.VISIBLE);
        else if(imagesState.get(position) == View.INVISIBLE)
            holder.icCancel.setVisibility(View.INVISIBLE);
        else
            holder.icCancel.setVisibility(View.GONE);
    }
}

Answer 2

使用

int position = recyclerView.getLayoutManager().findFirstVisibleItemPosition();

让第一个位置可见。然后只需滚动到该位置

recyclerView.getLayoutManager().scrollToPosition( <position of interest> );