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java - RecyclerView 中的复选框损坏

问题描述

我目前正在学习 Android Studio Java 编码，但遇到了麻烦。我使用 cardView 创建了 Recyclerview 并将复选框添加到 cardView。如果我创建新对象并选中它的复选框，它工作正常，删除线paintflag 工作。但是如果我添加另一个对象，它在第一个下面，我无法检查第一个对象，它不会改变它的paintflag。它工作的唯一方法是检查最后添加的对象，它可能对上面的所有 cardView 对象起作用（有时如果我取消选中上面的项目，删除线paintflag 不会删除）。

这是我的 CustomAdapter 代码：


import android.content.Context;
import android.graphics.Paint;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.lang.reflect.Array;
import java.util.ArrayList;

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder> {
    private Context context;
    private ArrayList book_id, book_title, book_author, book_pages;
    CheckBox checkBox;

    CustomAdapter(Context context,
                  ArrayList book_id,
                  ArrayList book_title,
                  ArrayList book_author,
                  ArrayList book_pages){

         this.context = context;
         this.book_id = book_id;
         this.book_title = book_title;
         this.book_author = book_author;
         this.book_pages = book_pages;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
       LayoutInflater inflater = LayoutInflater.from(context);
       View view = inflater.inflate(R.layout.my_row, parent, false);
       return new MyViewHolder(view);
    }

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

        holder.book_id_txt.setText(String.valueOf(book_id.get(position)));
        holder.book_title_txt.setText(String.valueOf(book_title.get(position)));
        holder.book_author_txt.setText(String.valueOf(book_author.get(position)));
        holder.book_pages_txt.setText(String.valueOf(book_pages.get(position)));
    }

    @Override
    public int getItemCount() {
        return book_id.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {

        TextView book_id_txt, book_title_txt, book_author_txt, book_pages_txt;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            book_id_txt = itemView.findViewById(R.id.book_id_txt);
            book_title_txt = itemView.findViewById(R.id.book_title_txt);
            book_author_txt = itemView.findViewById(R.id.book_author_txt);
            book_pages_txt = itemView.findViewById(R.id.book_pages_txt);
            checkBox = itemView.findViewById(R.id.checkBox);
            checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    if (checkBox.isChecked()){

                        book_author_txt.setPaintFlags(book_author_txt.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                        book_id_txt.setPaintFlags(book_id_txt.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                        book_pages_txt.setPaintFlags(book_pages_txt.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                        book_title_txt.setPaintFlags(book_title_txt.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);

                    } else {
                        book_author_txt.setPaintFlags(book_author_txt.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
                        book_id_txt.setPaintFlags(book_id_txt.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
                        book_pages_txt.setPaintFlags(book_pages_txt.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
                        book_title_txt.setPaintFlags(book_title_txt.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
                    }
                }
            });
        }
    }
}

如果你还需要什么，可以问我。我是初学者，所以可能是假的）请帮助我

标签： javaandroidandroid-recyclerview

解决方案

要防止 RecyclerView 被回收，请先将此行添加到您的 CustomAdapter：

@Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

同样在您onBindViewHolder尝试设置您的复选框默认状态时，例如：

if(condition){
holder.checkBox.setChecked(true);
}
else {
holder.checkBox.setChecked(false);
}

或者如果它只是未选中的默认值：

holder.checkBox.setChecked(false);

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