滚动时列表视图中的行会更改(Android Studio) [英] A row in List View changes when scrolled (Android Studio)

问题描述

我试图通过遵循本教程来创建多列列表视图:

http://techlovejump.com/android-multicolumn-listview/.

当记录量太大以至于整个视图超出了手机的屏幕时，就会发生问题.现在，当我滚动时，其中一行中的所有记录都在更改(它们的值已更改).其他所有行都很好.可能是什么问题?

 public class ListViewAdapters extends BaseAdapter{

    public ArrayList<HashMap<String, String>> list;
    Activity activity;
    TextView txtFirst;
    TextView txtSecond;
    TextView txtFourth;

    public ListViewAdapters(Activity activity, ArrayList<HashMap<String, String>> list){
        super();
        this.activity=activity;
        this.list=list;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }



    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        HashMap<String, String> map=list.get(position);
        LayoutInflater inflater=activity.getLayoutInflater();

        if(convertView == null)
        {
            if(map.get(MARKED)=="no")
             {
            convertView=inflater.inflate(R.layout.colmn_row, null);
             }
            else if (map.get(MARKED)=="yes")
            {
            convertView=inflater.inflate(R.layout.colmn_row_clicked, null);
            }
            txtFirst=(TextView) convertView.findViewById(R.id.name);
            txtSecond=(TextView) convertView.findViewById(R.id.gender);
            txtFourth=(TextView) convertView.findViewById(R.id.status);
        }

        txtFirst.setText(map.get(FIRST_COLUMN));
        txtSecond.setText(map.get(SECOND_COLUMN));
        txtFourth.setText(map.get(FOURTH_COLUMN));

        return convertView;
    }

}

解决方案

请尝试以下代码:

public class ListViewAdapters extends BaseAdapter {

public ArrayList<HashMap<String, String>> list;
Activity activity;
TextView txtFirst;
TextView txtSecond;
TextView txtFourth;

public ListViewAdapters(Activity activity, ArrayList<HashMap<String, String>> list){
    super();
    this.activity=activity;
    this.list=list;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return list.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return list.get(position);
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
}



@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    ViewHolder holder;
    HashMap<String, String> map=list.get(position);
    LayoutInflater inflater=activity.getLayoutInflater();

    if(convertView == null) {
        holder = new ViewHolder();
        if (map.get(MARKED) == "no") {
            convertView = inflater.inflate(R.layout.colmn_row, null);
        } else if (map.get(MARKED) == "yes") {
            convertView = inflater.inflate(R.layout.colmn_row_clicked, null);
        }
        holder.txtFirst = (TextView) convertView.findViewById(R.id.name);
        holder.txtSecond = (TextView) convertView.findViewById(R.id.gender);
        holder.txtFourth = (TextView) convertView.findViewById(R.id.status);

        holder.txtFirst.setText(map.get(FIRST_COLUMN));
        holder.txtSecond.setText(map.get(SECOND_COLUMN));
        holder.txtFourth.setText(map.get(FOURTH_COLUMN));
    }else {
        holder = (ViewHolder) convertView.getTag();
    }
    return convertView;
}

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

@Override
public int getViewTypeCount() {
    return getCount();
}

public class ViewHolder {
    TextView txtFirst, txtSecond,txtFourth;

}

}

I tried to create a multicolumn listview by following this tutorial:

http://techlovejump.com/android-multicolumn-listview/ .

The problem occured, when the amount of records was so big that the whole view exceeded the screen of a phone. Now when I'm scrolling, all of the records in one of the rows are changing (their values are changed). All the other rows are perfectly fine. What could be the problem?

 public class ListViewAdapters extends BaseAdapter{

    public ArrayList<HashMap<String, String>> list;
    Activity activity;
    TextView txtFirst;
    TextView txtSecond;
    TextView txtFourth;

    public ListViewAdapters(Activity activity, ArrayList<HashMap<String, String>> list){
        super();
        this.activity=activity;
        this.list=list;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }



    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        HashMap<String, String> map=list.get(position);
        LayoutInflater inflater=activity.getLayoutInflater();

        if(convertView == null)
        {
            if(map.get(MARKED)=="no")
             {
            convertView=inflater.inflate(R.layout.colmn_row, null);
             }
            else if (map.get(MARKED)=="yes")
            {
            convertView=inflater.inflate(R.layout.colmn_row_clicked, null);
            }
            txtFirst=(TextView) convertView.findViewById(R.id.name);
            txtSecond=(TextView) convertView.findViewById(R.id.gender);
            txtFourth=(TextView) convertView.findViewById(R.id.status);
        }

        txtFirst.setText(map.get(FIRST_COLUMN));
        txtSecond.setText(map.get(SECOND_COLUMN));
        txtFourth.setText(map.get(FOURTH_COLUMN));

        return convertView;
    }

}

解决方案

Please try this code:

public class ListViewAdapters extends BaseAdapter {

public ArrayList<HashMap<String, String>> list;
Activity activity;
TextView txtFirst;
TextView txtSecond;
TextView txtFourth;

public ListViewAdapters(Activity activity, ArrayList<HashMap<String, String>> list){
    super();
    this.activity=activity;
    this.list=list;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return list.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return list.get(position);
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
}



@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    ViewHolder holder;
    HashMap<String, String> map=list.get(position);
    LayoutInflater inflater=activity.getLayoutInflater();

    if(convertView == null) {
        holder = new ViewHolder();
        if (map.get(MARKED) == "no") {
            convertView = inflater.inflate(R.layout.colmn_row, null);
        } else if (map.get(MARKED) == "yes") {
            convertView = inflater.inflate(R.layout.colmn_row_clicked, null);
        }
        holder.txtFirst = (TextView) convertView.findViewById(R.id.name);
        holder.txtSecond = (TextView) convertView.findViewById(R.id.gender);
        holder.txtFourth = (TextView) convertView.findViewById(R.id.status);

        holder.txtFirst.setText(map.get(FIRST_COLUMN));
        holder.txtSecond.setText(map.get(SECOND_COLUMN));
        holder.txtFourth.setText(map.get(FOURTH_COLUMN));
    }else {
        holder = (ViewHolder) convertView.getTag();
    }
    return convertView;
}

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

@Override
public int getViewTypeCount() {
    return getCount();
}

public class ViewHolder {
    TextView txtFirst, txtSecond,txtFourth;

}

}

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