在recyclerview中更改所选项目的背景颜色

Question

如何在我的回收视图示例中更改仅选定视图的背景颜色？只需要更改单击的项目视图的背景颜色。一次只能显示一个选择的项目并改变背景颜色，其余的需要与选择前一样。这是我的代码：

主要活动

public class MainActivity extends AppCompatActivity {
RecyclerView rv1;
    private  final String android_versions[]={
                "Donut",
                "Eclair",
                "Froyo",
                "Gingerbread",
                "Honeycomb",
                "Ice Cream Sandwich",
                "Jelly Bean",
                "KitKat",
                "Lollipop",
                "Marshmallow"
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
    }

    private  void initViews(){
        rv1=(RecyclerView)findViewById(R.id.recyclerView1);
        rv1.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager=new LinearLayoutManager(getApplicationContext());
        rv1.setLayoutManager(layoutManager);

        RecyclerDataAdapter rda=new RecyclerDataAdapter(rv1,getApplicationContext(),android_versions);
        rv1.setAdapter(rda);
    }
}

RecyclerDataadapter

 public class RecyclerDataAdapter extends RecyclerView.Adapter<RecyclerDataAdapter.ViewHolder> {

private String android_versionnames[];
    private Context context1;

    private RecyclerView mRecyclerView;

    public RecyclerDataAdapter(RecyclerView recylcerView,Context context,String android_versionnames[]){
        this.android_versionnames=android_versionnames;
        this.context1=context;
mRecyclerView=recylcerView;
        setHasStableIds(true);
        System.out.println("Inside dataadapter,Android names : \n ");
        for(int i=0;i<android_versionnames.length;i++){
            System.out.println("\n"+android_versionnames[i]);
        }
    }

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

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.tv1.setText(android_versionnames[position]);
    }

    @Override
    public int getItemCount() {
        return android_versionnames.length;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        private TextView tv1;
        LinearLayout row_linearlayout;
        RecyclerView rv2;

        public ViewHolder(final View itemView) {
            super(itemView);
            tv1=(TextView)itemView.findViewById(R.id.txtView1);
            row_linearlayout=(LinearLayout)itemView.findViewById(R.id.row_linrLayout);
            rv2=(RecyclerView)itemView.findViewById(R.id.recyclerView1);
            /*itemView.setBackgroundColor(0x00000000);//to transparent*/

        }
    }
}

原文由 c0der 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

最后，我得到了答案。

 public void onBindViewHolder(final ViewHolder holder, final int position) {
        holder.tv1.setText(android_versionnames[position]);

        holder.row_linearlayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                row_index=position;
                notifyDataSetChanged();
            }
        });
        if(row_index==position){
            holder.row_linearlayout.setBackgroundColor(Color.parseColor("#567845"));
            holder.tv1.setTextColor(Color.parseColor("#ffffff"));
        }
        else
        {
            holder.row_linearlayout.setBackgroundColor(Color.parseColor("#ffffff"));
            holder.tv1.setTextColor(Color.parseColor("#000000"));
        }

    }

这里’row_index’最初设置为’-1’

 public class ViewHolder extends RecyclerView.ViewHolder {
        private TextView tv1;
        LinearLayout row_linearlayout;
        RecyclerView rv2;

        public ViewHolder(final View itemView) {
            super(itemView);
            tv1=(TextView)itemView.findViewById(R.id.txtView1);
            row_linearlayout=(LinearLayout)itemView.findViewById(R.id.row_linrLayout);
            rv2=(RecyclerView)itemView.findViewById(R.id.recyclerView1);
        }
    }

原文由 c0der 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

当您需要更改一项时，调用 Notifydatasetchanged 可能会很昂贵我们可以通过保存旧位置并调用 notifyItemChanged 来克服

var old_postion=-1

   public void onBindViewHolder(final ViewHolder holder, final int position) {
    holder.tv1.setText(android_versionnames[position]);

    holder.row_linearlayout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            notifyItemChanged(old_position)
           //After item change happens set the old_postion as current position
            old_position=position
        }
    });
    if(old_position==position){
        holder.row_linearlayout.setBackgroundColor(Color.parseColor("#567845"));
        holder.tv1.setTextColor(Color.parseColor("#ffffff"));
    }
    else
    {
        holder.row_linearlayout.setBackgroundColor(Color.parseColor("#ffffff"));
        holder.tv1.setTextColor(Color.parseColor("#000000"));
    }

}

原文由 Android Development 发布，翻译遵循 CC BY-SA 4.0 许可协议