在recyclerview中更改所选项目的背景颜色

Question

如何在循环视图示例中仅更改所选视图的背景颜色？只需更改单击项目视图的背景颜色.一次只能显示一个选定项目,背景颜色会发生变化,其余项目必须与选择前一样.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*/

        }
    }
}

Answer 1

感谢重播家伙..终于我得到了答案..

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);
        }
    }

Answer 2

实现这一目标的一个非常简单的方法是:

//instance variable
List<View>itemViewList = new ArrayList<>();

//OnCreateViewHolderMethod
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {    
    final View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_row, parent, false);
    final MyViewHolder myViewHolder = new MyViewHolder(itemView);

    itemViewList.add(itemView); //to add all the 'list row item' views

    //Set on click listener for each item view
    itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for(View tempItemView : itemViewList) {
                /** navigate through all the itemViews and change color
                of selected view to colorSelected and rest of the views to colorDefault **/
                if(itemViewList.get(myViewHolder.getAdapterPosition()) == tempItemView) {
                    tempItemView.setBackgroundResource(R.color.colorSelected);
                }
                else{
                    tempItemView.setBackgroundResource(R.color.colorDefault);
                }
            }
        }
    });
    return myViewHolder;
}

UPDATE

上面的方法可能会破坏itemView的一些默认属性,在我的例子中,我使用的是CardView,并且卡片的角半径在点击时被移除.

更好的方案:

//instance variable
List<CardView>cardViewList = new ArrayList<>();

public class MyViewHolder extends RecyclerView.ViewHolder {
        CardView cardView; //THIS IS MY ROOT VIEW
        ...

        public MyViewHolder(View view) {
            super(view);
            cardView = view.findViewById(R.id.row_item_card);
            ...
        }
}

@Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        final OurLocationObject locationObject = locationsList.get(position);
        ...

        cardViewList.add(holder.cardView); //add all the cards to this list

        holder.cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //All card color is set to colorDefault
                for(CardView cardView : cardViewList){
                cardView.setCardBackgroundColor(context.getResources().getColor(R.color.colorDefault));
                }
                //The selected card is set to colorSelected
                holder.cardView.setCardBackgroundColor(context.getResources().getColor(R.color.colorSelected));
            }
        });
}

更新2 - 重要

onBindViewHolder方法被多次调用,并且每次用户将视图滚动到视线之外并且回到视线中时!这将导致相同的视图多次添加到列表中,这可能会导致问题和代码执行的轻微延迟!

要解决这个问题,请 更改

cardViewList.add(holder.cardView);

至

if (!cardViewList.contains(holder.cardView)) {
    cardViewList.add(holder.cardView);
}

Answer 3

在Drawable文件夹中创建Drawable文件

<item android:drawable="@color/SelectedColor" android:state_pressed="true"></item>
<item android:drawable="@color/SelectedColor" android:state_selected="true"></item>
<item android:drawable="@color/DefultColor"></item>

并在 xml 文件中

android:background="@drawable/Drawable file"

在 RecyclerView 中的 BindViewHolder 上

holder.button.setSelected(holder.button.isSelected()?true:false);

就像切换按钮一样

Answer 4

我可以建议我在应用程序中使用过的解决方案。我已将onTouchListener的代码放在我的ViewHolder类的构造函数中。itemView是构造函数的参数。确保在此方法上使用return false，因为这需要工作OnClickListener

itemView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if(event.getAction() == MotionEvent.ACTION_DOWN)
        {
            v.setBackgroundColor(Color.parseColor("#f0f0f0"));
        }
        if (event.getAction() == MotionEvent.ACTION_UP || event.getAction() == MotionEvent.ACTION_CANCEL)
        {
            v.setBackgroundColor(Color.TRANSPARENT);
        }
        return false;
    }
});