RecyclerView中的损坏复选框

Question

我目前正在学习Android studio Java编码，遇到了麻烦。我使用cardView创建了Recyclerview，并在cardView中添加了复选框。如果我创建了一个新对象并选中了它的复选框，它就可以正常工作，删除paintflag也可以。但如果我添加了另一个对象，它在第一个对象下面，我就不能检查第一个对象，因为它没有改变它的paintflag。它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对象都有效(有时如果我取消选中上面的项目，则删除线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，问我。我是初学者，所以可能是个傻瓜(请帮我

Answer 1

要防止RecyclerView回收，请首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;
}

也可以在onBindViewHolder上尝试设置复选框的默认状态，如：

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

或者如果它只是未检查的默认值：

holder.checkBox.setChecked(false);

Answer 2

还有一件事。我知道这是个老问题，但我今天还是遇到了这个问题。

NEVER EVER 从不使用checkBox.setOnCheckedChangeListener

RecyclerView.Adapter<?>.onBindViewHolder内部！！！

它在回收过程中触发！！

改为这样使用：

final DeviceItem item = items.get( position );
if( null != holder.tToggle ) {
Utils.logData( item.getName() + " is selected: " + item.isSelected() );
holder.tToggle.setChecked( item.isSelected() );
holder.tToggle.setOnClickListener( v -> {
CheckBox ch = (CheckBox)v;
item.setSelected( ch.isChecked() );
} );
}