复选框取消选中得到卷轴上的自定义列表视图 [英] CheckBox gets unchecked on scroll in a custom listview

问题描述

我知道这个问题已经被问了一遍又一遍，但我仍然一直没有一个能够找到一个建议，真正帮助我。该复选框被选中，只要在列表中向下滚动。是的，我使用的是布尔数组来存储值，但是这仍然没有解决问题。这是我的code。请提出一个解决方案。谢谢你。

 公开查看getView（最终诠释的立场，观点convertView，ViewGroup中父）{
    // TODO自动生成方法存根
        最后ViewHolder持有人;
最终布尔[] itemChecked =新的布尔[30];

    LayoutInflater充气= context.getLayoutInflater（）;
    如果（convertView == NULL）
    {
        convertView = inflater.inflate（R.layout.custom_list，NULL）;
        持有人=新ViewHolder（）;
        holder.txtViewTitle =（TextView中）convertView.findViewById（R.id.title_text）;
        holder.txtViewDescription =（TextView中）convertView.findViewById（R.id.description_text）;
        holder.cb =（复选框）convertView.findViewById（R.id.cb）;
        convertView.setTag（保持器）;

    }

    其他
    {
        支架=（ViewHolder）convertView.getTag（）;

     }

    holder.cb.setOnCheckedChangeListener（新CompoundButton.OnCheckedChangeListener（）{

            @覆盖
            公共无效onCheckedChanged（CompoundButton buttonView，布尔器isChecked）{
                // TODO自动生成方法存根
                 itemChecked [位置] =器isChecked;
                 如果（itemChecked [位置]）
                 {
                     holder.cb.setChecked（真正的）;
                 }
                 其他
                 {
                     holder.cb.setChecked（假）;
                 }
      holder.txtViewTitle.setText（标题[位置]）;
    holder.txtViewDescription.setText（介绍[位置]）;
    holder.cb.setChecked（itemChecked [位置]）;
  holder.txtViewDescription.setFocusable（假）;
  holder.txtViewTitle.setFocusable（假）;

返回convertView;

}

}
 

解决方案

getView（）被调用只要previously看不见的列表项需要绘制。既然你重新创建 itemChecked [] 每次调用此方法时，你将有新的复选框选中和不同阵列的每个结果显示的时间。 （最终在Java中不会使该领域独特的像C） 最简单的解决方法是让 itemChecked A classmember并设置/基于一个恢复复选框的状态。

 公共类MyListAdapter扩展ArrayAdapter＆LT;对象＆gt; {
    私人最终布尔[] mCheckedState;
    私人最终语境mContext;

    公共MyListAdapter（上下文的背景下，INT资源，INT textViewResourceId，列表和LT;对象＆gt;的对象）{
        超（背景下，资源，textViewResourceId，对象）;
        mCheckedState =新的布尔[objects.size（）];
        mContext =背景;
    }


    @覆盖
    公共查看getView（INT位置，查看convertView，ViewGroup中父）{
        //简化为一个复选框
        // ViewHolder和OnCheckedChangeListener东西离开了
        复选框结果=（复选框）convertView;
        如果（结果== NULL）{
            结果=新的复选框（mContext）;
        }
        result.setChecked（mCheckedState [位置]）;
        返回结果;
    }
}
 

I know that this question has been asked over and over again but still I've not been a able to find a suggestion that really helps me. The checkbox is unchecked whenever the list is scrolled down. Yes I'm using a boolean array to store the values but this still doesn't fix the problem. Here is my code. Please suggest a solution for this. Thank you.

 public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
        final ViewHolder holder;
final boolean[] itemChecked=new boolean[30];

    LayoutInflater inflater =  context.getLayoutInflater();  
    if(convertView==null)  
    {  
        convertView = inflater.inflate(R.layout.custom_list, null);
        holder = new ViewHolder();  
        holder.txtViewTitle = (TextView) convertView.findViewById(R.id.title_text);  
        holder.txtViewDescription = (TextView) convertView.findViewById(R.id.description_text);  
        holder.cb=(CheckBox) convertView.findViewById(R.id.cb);
        convertView.setTag(holder);  

    }  

    else  
    {
        holder=(ViewHolder)convertView.getTag();  

     }  

    holder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                // TODO Auto-generated method stub
                 itemChecked[position] = isChecked;
                 if(itemChecked[position])
                 {
                     holder.cb.setChecked(true);
                 }
                 else
                 {
                     holder.cb.setChecked(false);
                 }
      holder.txtViewTitle.setText(title[position]);  
    holder.txtViewDescription.setText(description[position]);  
    holder.cb.setChecked(itemChecked[position]);
  holder.txtViewDescription.setFocusable(false);
  holder.txtViewTitle.setFocusable(false);

return convertView;  

}  

}

解决方案

getView() is called whenever a previously invisible list item needs to be drawn. Since you recreate itemChecked[] each time this method is called you will have the new checkbox unchecked and a different Array for each resulting View. (final in Java does not make that field unique like in C) Simplest way to solve that is to make itemChecked a classmember and set / restore checkbox state based on that one.

public class MyListAdapter extends ArrayAdapter<Object> {
    private final boolean[] mCheckedState;
    private final Context mContext;

    public MyListAdapter(Context context, int resource, int textViewResourceId, List<Object> objects) {
        super(context, resource, textViewResourceId, objects);
        mCheckedState = new boolean[objects.size()];
        mContext = context;
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // simplified to just a Checkbox
        // ViewHolder and OnCheckedChangeListener stuff left out 
        CheckBox result = (CheckBox)convertView;
        if (result == null) {
            result = new CheckBox(mContext);
        }
        result.setChecked(mCheckedState[position]);
        return result;
    }
}

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