Android Kotlin 中的 RecyclerView 效果选定项

Question

编程语言：KOTLIN

库：androidX

我在 Kotlin 中使用来自 AndroidX 库的 RecyclerView，但出现了一个问题。

问题：当我点击第一个显示项目时，更多项目会受到影响，总是在 10 个项目之后。

示例：如果单击第一个项目，则项目 1、11、21,31 也会受到影响。

这里是代码

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.recyclerview.widget.RecyclerView
import com.jdwebservices.mybigbachat.R
import com.jdwebservices.mybigbachat.data.products
import com.squareup.picasso.Picasso
import kotlinx.android.synthetic.main.product_row.view.*
import kotlin.collections.ArrayList


class product_adapter(var contet:Context, var catlist: ArrayList<products>): RecyclerView.Adapter<RecyclerView.ViewHolder>(){
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val v:View=LayoutInflater.from(contet).inflate(R.layout.product_row,parent,false)
        return clientHolders(v)
    }
    override fun getItemCount(): Int {
        return catlist.size
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        holder.itemView.setOnClickListener { }
         (holder as clientHolders).bind(
           catlist[position].product_name_app_english,
           catlist[position].product_image,
           catlist[position].mrp,
           catlist[position].sale_rate,
             position
       )
    }

    class clientHolders(itemView: View): RecyclerView.ViewHolder(itemView)
    {
        val BASE_URL = "https://mybachatbasket.xyz/"
        var counter = -1
        fun bind(
            product_name_app_english: String,
            product_image: String,
            mrp: Int,
            sale_rate: Int,
            products: Int
        ) {
            if (counter == -1) {
                itemView.add_1.visibility = View.VISIBLE
                itemView.add_to_cart.visibility = View.GONE
            }
            var pos = adapterPosition
            if(pos == products){
            itemView.product_name.text = product_name_app_english

            itemView.mrp_full.visibility = View.VISIBLE
            itemView.mrp.text = mrp.toString()
            itemView.sale_rate.text = sale_rate.toString()

            var eb: String = BASE_URL + "admin/resource/uploads/" + product_image
            eb = eb.replace(" ", "%20")
            Picasso.get().load(eb).into(itemView.product_image)

            itemView.add_1.setOnClickListener {

                counter = 1
                 Toast.makeText(itemView.context, pos.toString(),Toast.LENGTH_LONG).show()
               // Toast.makeText(itemView.context, products.toString(), Toast.LENGTH_LONG).show()
                //  add_cart(product_id,category_id,counter)
if (pos >= 0) {
    itemView.add_1.visibility = View.GONE
    itemView.add_to_cart.visibility = View.VISIBLE
    itemView.count.text = counter.toString()
}else{
    itemView.add_1.visibility = View.VISIBLE
    itemView.add_to_cart.visibility = View.GONE

}

            }

            itemView.add.setOnClickListener {

                counter++
                itemView.count.text = counter.toString()

            }
            itemView.delete.setOnClickListener {

                counter--
                itemView.count.text = counter.toString()
                //  updtae_cart(last_id,counter);
                if (counter == 0) {
                    itemView.add_1.visibility = View.VISIBLE
                    itemView.add_to_cart.visibility = View.GONE
                }

            }

        }
        }

    }


}

Answer 1

recyclerview 回收OnBindViewHolder 中的视图。因此，当单击项目时，它会反映在其他一些位置。

要更好地了解recyclerview 的选择状态，请参阅this example

在你的model 类中添加一个名为isSelected 的额外属性，其中getter 和setter 类似

public class YourModel{
    // your other properties

    private boolean isSelected;

    public boolean getSelected() {
        return isSelected;
    }

    public void setSelected(boolean selected) {
        isSelected = selected;
    }
}

并且在您的适配器中，如果用户单击该项目，您必须将isSelected 设置为true，否则您的onBindViewHolder() 内将是错误的。下面是一个例子

@Override
    public void onBindViewHolder(final CustomAdapter.MyViewHolder holder, int position) {
        holder.checkBox.setText("Checkbox " + position);

        // here you can check is this item clicked or not 
        if(imageModelArrayList.get(position).getSelected()){
           holder.checkBox.setChecked(true);
        }

        holder.tvAnimal.setText(imageModelArrayList.get(position).getAnimal());
        holder.checkBox.setTag(position);
        holder.checkBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Integer pos = (Integer) holder.checkBox.getTag();
                Toast.makeText(ctx, imageModelArrayList.get(pos).getAnimal() + " clicked!", Toast.LENGTH_SHORT).show();

                if (imageModelArrayList.get(pos).getSelected()) {
                    imageModelArrayList.get(pos).setSelected(false);
                } else {
                    imageModelArrayList.get(pos).setSelected(true);
                }
            }
        });


    }

希望对你有所帮助。