Question

我正在认真学习Android Studio Java编码，但遇到了麻烦。我使用cardView创建了Recyclerview，并向cardView添加了复选框。如果我创建一个新对象并选中它的复选框，它会正常工作，strittrough paintflag会工作。但是，如果我添加了另一个对象，该对象位于第一个对象之下，则无法检查第一个对象，它不会更改其paintflag。它唯一的工作方式是检查最后添加的对象，并且可能对上面的所有cardView对象都起作用（有时，如果我取消选中上面的项目，则删除走线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));
                    }
                }
            });
        }
    }
}

如果您还有其他需要，请问我。我是乞gg，所以可能是个假人）请帮助我

Answer 1

要防止RecyclerView回收，请首先将此行添加到CustomAdapter：

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

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

还要在您的onBindViewHolder上尝试将复选框的默认状态设置为：

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

，或者如果它只是未经检查的默认值：

holder.checkBox.setChecked(false);

RecyclerView中损坏的复选框

1 个答案: