Android TV 中的 RecyclerView 项目焦点

Posted 2023-04-15

【中文标题】Android TV 中的 RecyclerView 项目焦点

【英文标题】：RecyclerView item focus in Android TV

【发布时间】：2020-10-11 05:54:30

【问题描述】：

如何在 android tv 应用中关注 recyclerview 项目？

我在 Horizo​​ntal Recyclerview 的右侧使用带有 Imageview 的 recyclerview。

【问题讨论】：

在定义 ImageView 的 xml 中添加这两个属性 "android:focusable=true","android:focusableInTouchMode=true"

【参考方案1】：

public abstract class TrackSelectionAdapter<VH extends TrackSelectionAdapter.ViewHolder> extends RecyclerView.Adapter<VH> 
    // Start with first item selected
    private int selectedItem = 0;

    @Override
    public void onAttachedToRecyclerView(final RecyclerView recyclerView) 
        super.onAttachedToRecyclerView(recyclerView);

        // Handle key up and key down and attempt to move selection
        recyclerView.setOnKeyListener(new View.OnKeyListener() 
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) 
                RecyclerView.LayoutManager lm = recyclerView.getLayoutManager();

                // Return false if scrolled to the bounds and allow focus to move off the list
                if (event.getAction() == KeyEvent.ACTION_DOWN) 
                    if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) 
                        return tryMoveSelection(lm, 1);
                     else if (keyCode == KeyEvent.KEYCODE_DPAD_UP) 
                        return tryMoveSelection(lm, -1);
                    
                

                return false;
            
        );
    

    private boolean tryMoveSelection(RecyclerView.LayoutManager lm, int direction) 
        int nextSelectItem = selectedItem + direction;

        // If still within valid bounds, move the selection, notify to redraw, and scroll
        if (nextSelectItem &gt;= 0 &amp;&amp; nextSelectItem &lt; getItemCount()) 
            notifyItemChanged(selectedItem);
            selectedItem = nextSelectItem;
            notifyItemChanged(selectedItem);
            lm.scrollToPosition(selectedItem);
            return true;
        

        return false;
    

    @Override
    public void onBindViewHolder(VH viewHolder, int position) 
        // Set selected state; use a state list drawable to style the view
        viewHolder.itemView.setSelected(selectedItem == position);
    

    public class ViewHolder extends RecyclerView.ViewHolder 
        public ViewHolder(View itemView) 
            super(itemView);

            // Handle item click and set the selection
            itemView.setOnClickListener(new View.OnClickListener() 
                @Override
                public void onClick(View v) 
                    // Redraw the old selection and the new
                    notifyItemChanged(selectedItem);
                    selectedItem = mRecyclerView.getChildPosition(v);
                    notifyItemChanged(selectedItem);
                
            );