如何在回收者查看项目点击时跟踪项目选择？

Question

当用户click任何项目时，我想突出显示recyclerview项目，而上一个项目将被unselected请帮助？

Answer 1

For this you have to write a selector.

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/colorAccent" android:state_selected="true" />
    <item android:drawable="@color/ash" android:state_selected="false" />
    <item android:drawable="@color/ash" />
</selector>

In-order to get the desired behavior on the onClick you have to make the item selected explicitly.

public class CellAdapter extends RecyclerView.Adapter<CellAdapter.ViewHolder> {
    private Context context;
    private View prevView;

    public CellAdapter(Context context) {
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycle_cell, parent, false);
        CellAdapter.ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

    }

    @Override
    public int getItemCount() {
        return 10;
    }

    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {  

        public ViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            if (prevView != null) {
                prevView.setSelected(false);
            }
            v.setSelected(true);
            prevView = v;
            Toast.makeText(context, String.valueOf(getAdapterPosition()), Toast.LENGTH_SHORT).show();
        }
    }
}

And make sure that you have Set clickable true for recycleView.

<android.support.v7.widget.RecyclerView 
    android:id="@+id/recycle_view"
    android:layout_width="wrap_content"
    android:clickable="true"
    android:focusable="true"
    android:layout_height="wrap_content" />