问题：

ListView数据在滚动时被清除[重复]

经嘉

2023-03-14

我正在开发一个应用程序，它显示带有复选框的listView。当我滚动列表查看复选框的值被清除时。

下面是我的代码

适配器类别:

public class Conference_listViewAdapter extends BaseAdapter {
    Activity context;
    LayoutInflater inflater;
    public static List<Model> data = null;
    ArrayList<String> id_list = new ArrayList<String>();
    ViewHolder holder;
    int pos;

    public Conference_listViewAdapter(Activity context,List<Model> list, ArrayList<String> id_list) {
        data = list;
        this.id_list = id_list;     
        this.context = context;
    }


    @Override
    public int getCount() {
        return data.size();
    }


    @Override
    public Object getItem(int position) {
        return data.get(position).getName();
    }

    @Override
    public long getItemId(int position) {
        return Long.valueOf(id_list.get(position));
    }

    public View getView(final int position, View convertView, ViewGroup parent) {

        View view = null;

        if (convertView == null) {
            LayoutInflater inflator = context.getLayoutInflater();
            view = inflator.inflate(R.layout.people_list_item1, null);
            holder = new ViewHolder();
            holder.title = (TextView) view.findViewById(R.id.tv_name);
            holder.image = (ImageView) view.findViewById(R.id.avtaar);
            holder.favorite = (CheckBox) view.findViewById(R.id.fav);
            holder.favorite.setTag(position);
            view.setTag(holder);

            holder.favorite.setTag(data.get(position));
        } else {
            view = convertView;
            ((ViewHolder) view.getTag()).favorite.setTag(data.get(position));
        }


        holder.favorite.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {                    
                Model element = (Model) holder.favorite.getTag();
                element.setSelected(buttonView.isChecked());     
                //notifyDataSetChanged();
            }
        });


        ViewHolder holder = (ViewHolder) view.getTag();

        holder.favorite.setChecked(data.get(position).isSelected());
        holder.title.setText(data.get(position).getName());



        try {
            holder.image.setImageBitmap(openPhoto(Long.valueOf(id_list.get(position))));
        } catch (Exception e) {
            e.printStackTrace();
        }

        return view;
    }

    class ViewHolder {
        TextView title;
        TextView model;
        ImageView image;
        CheckBox favorite;
    }


}

数据模型类

public class Model {

    private String name;
    private boolean selected;

    public Model(String name) {
        this.name = name;
        selected = false;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public boolean isSelected() {
        return selected;
    }

    public void setSelected(boolean selected) {
        this.selected = selected;
    }

}

不知道我哪里做错了。

共有3个答案

丁立果

2023-03-14

在类似的情况下，例如带有复选框，单选按钮，计数框等的列表视图，我使用如下方式1）保留一个大小类似于listview（行数）的数组列表2）此数组/数组列表将在适配器类的构造函数中初始化，所有位置为零3）在声明复选框并将其标记设置为位置后在getView（）中声明复选框并将其标签设置为位置

public class Conference_listViewAdapter extends BaseAdapter {
    Activity context;
    LayoutInflater inflater;
    public static List<Model> data = null;
    ArrayList<String> id_list = new ArrayList<String>();
     ArrayList<String> myarray=new java.util.ArrayList<String>();   
    ViewHolder holder;
    int pos;


    public Conference_listViewAdapter(Activity context,List<Model> list, ArrayList<String> id_list) {
        data = list;
        this.id_list = id_list;
        this.context = context;
for(int i=0;i<id_list.size();i++)
myarray.add("0");
    }


    @Override
    public int getCount() {
        return data.size();
    }


    @Override
    public Object getItem(int position) {
        return position;
    }

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

    public View getView(final int position, View convertView, ViewGroup parent) {

        View view = null;

        if (convertView == null) {
            LayoutInflater inflator = context.getLayoutInflater();
            view = inflator.inflate(R.layout.people_list_item1, null);
            holder = new ViewHolder();
            holder.title = (TextView) view.findViewById(R.id.tv_name);
            holder.image = (ImageView) view.findViewById(R.id.avtaar);
            holder.favorite = (CheckBox) view.findViewById(R.id.fav);
            holder.favorite.setTag(position);
            view.setTag(holder);

if(myarray.get(Integer.parseInt(holder.favorite.getTag().toString()).equalsIgnoreCase("1")
//make your checkbox checked
else
//keep checkbox unchecked
            holder.favorite.setOnCheckedChangeListener(new OnCheckedChangeListener() {

                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {                    
   if(  isChecked)                   myarray.set(Integer.parseInt(holder.favorite.getTag().toString()),"1");    

else
myarray.set(Integer.parseInt(holder.favorite.getTag().toString()),"0"); 

notifydatasetchanged();
            });

            holder.favorite.setTag(data.get(position));
        } else {
            view = convertView;
            ((ViewHolder) view.getTag()).favorite.setTag(data.get(position));
        }


        ViewHolder holder = (ViewHolder) view.getTag();

        holder.favorite.setChecked(data.get(position).isSelected());
        holder.title.setText(data.get(position).getName());



        try {
            holder.image.setImageBitmap(openPhoto(Long.valueOf(id_list.get(position))));
        } catch (Exception e) {
            e.printStackTrace();
        }

        return view;
    }

    class ViewHolder {
        TextView title;
        TextView model;
        ImageView image;
        CheckBox favorite;
        Boolean selected;
    }   

}

总是这保存我的问题与列表视图滚动...

司空凌

2023-03-14

改变这个...

  @Override
public Object getItem(int position) {
    return position;
}

到..

  @Override
public Object getItem(int position) {
    return data.get(position);
}

更新：

试试这个。。

public View getView(final int position, View convertView, ViewGroup parent) {

    View view = null;

    if (convertView == null) {
        LayoutInflater inflator = context.getLayoutInflater();
        view = inflator.inflate(R.layout.people_list_item1, null);
        holder = new ViewHolder();
        holder.title = (TextView) view.findViewById(R.id.tv_name);
        holder.image = (ImageView) view.findViewById(R.id.avtaar);
        holder.favorite = (CheckBox) view.findViewById(R.id.fav);
        holder.favorite.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {                    
               //do what you want..   
            }
        });

        view.setTag(holder);
    } else {
       holder = (ViewHolder) view.getTag();
    }

    holder.favorite.setChecked(data.get(position).isSelected());
    holder.title.setText(data.get(position).getName());



    try {
        holder.image.setImageBitmap(openPhoto(Long.valueOf(id_list.get(position))));
    } catch (Exception e) {
        e.printStackTrace();
    }

    return view;
}

支铭晨

2023-03-14

您必须保存视图持有人的状态。然后在convertView==null时设置标记，并将其置于或条件下。

检查我做的方式:

public class Conference_listViewAdapter extends ArrayAdapter<Model> {
    Activity context;
    LayoutInflater inflater;
    public static List<Model> data = null;
    ArrayList<String> id_list = new ArrayList<String>();

    int pos;


    public Conference_listViewAdapter(Activity context, List<Model> list, ArrayList<String> id_list) {
        super(context, R.layout.people_list_item1, list);
        this.context = context;
        this.data = list;
        this.id_list = id_list; 
    }



    public View getView(final int position, View convertView, ViewGroup parent) {
        View view = null;       
        if (convertView == null) {
            LayoutInflater inflator = context.getLayoutInflater();
            view = inflator.inflate(R.layout.people_list_item1, null);
            final ViewHolder holder = new ViewHolder();
            holder.title = (TextView) view.findViewById(R.id.tv_name);
            holder.image = (ImageView) view.findViewById(R.id.avtaar);
            holder.favorite = (CheckBox) view.findViewById(R.id.fav);

            view.setTag(holder);

            holder.favorite.setTag(data.get(position));

            holder.favorite.setOnCheckedChangeListener(new OnCheckedChangeListener() {

                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {                    
                    Model element = (Model) holder.favorite.getTag();
                    element.setSelected(buttonView.isChecked());     
                }
            });


        } else {
            view = convertView;
            ((ViewHolder) view.getTag()).favorite.setTag(data.get(position));
        }





        ViewHolder holder = (ViewHolder) view.getTag();     
        holder.favorite.setChecked(data.get(position).isSelected());
        holder.title.setText(data.get(position).getName());

        try {
            holder.image.setImageBitmap(openPhoto(Long.valueOf(id_list.get(position))));
        } catch (Exception e) {
            e.printStackTrace();
        }

        return view;
    }




    static class ViewHolder {
        protected TextView title;
        protected CheckBox favorite;
        ImageView image;
    }

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共有3个答案

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