When scrolling custom ListView, the checkbox value changes

Question

What I have: a custom listview with Textviews and checkbox.

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Problem: Suppose my screen can show only 6 items of list at time, and

Answer 1

check this code

public class NewQAAdapterSelectFriends extends BaseAdapter {
private LayoutInflater mInflater;
private Person[] data;
ArrayList checkedItem=new ArrayList();

public NewQAAdapterSelectFriends(Context context) { 
    mInflater = LayoutInflater.from(context);
}

public void setData(Person[] data) {
    this.data = data;
}

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

@Override
public Object getItem(int item) {
    return data[item];
}

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



@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.item_select_friends, null);
        final ViewHolder viewHolder = new ViewHolder();
        viewHolder.nameText=(TextView) convertView.findViewById(R.id.personName);
        viewHolder.surnameText=(TextView) convertView.findViewById(R.id.personSurname);
        viewHolder.contactImage=(ImageView) convertView.findViewById(R.id.personImage);
        viewHolder.checkBox=(CheckBox)convertView.findViewById(R.id.checkBox);
        convertView.setTag(viewHolder);
        viewHolder.nameText.setTag(viewHolder.nameText);
        viewHolder.nameText.setTag(viewHolder.surnameText);
        viewHolder.contactImage.setTag(data[position]);
        viewHolder.checkBox.setOnCheckedChangeListener(
                new CompoundButton.OnCheckedChangeListener() {
                    @Override
                    public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
                        Person element = (Person) viewHolder.checkBox.getTag();

                        if(isChecked){
                            getCheckList(data[position],isChecked);
                        }
                        else{
                            getCheckList(data[position],isChecked);    
                        }

                    }
                });
        viewHolder.checkBox.setTag(data[position]);
    } 
     ViewHolder holder = (ViewHolder) convertView.getTag();
     holder.nameText.setText(data[position].getName());
     holder.surnameText.setText(data[position].getSurname());
     holder.contactImage.setImageResource(data[position].getPhotoRes());
     holder.contactImage.setScaleType(ScaleType.FIT_XY);
     if(checkedItem != null && checkedItem.contains(data[position])){
        viewHolder.checkBox.setChecked(true);
     }else
     {
        viewHolder.checkBox.setChecked(false);
     } 
    return convertView;
}

static class ViewHolder {
    TextView nameText;
    TextView surnameText;
    ImageView contactImage;
    CheckBox checkBox;
}
public void getCheckList(String value,boolean status){
        if(!checkedItem.contains(value)  && status)
        {
            checkedItem.add(value);
        }
        if(checkedItem.contains(value)  && !status)
        {
            checkedItem.remove(value);
        }
    }
}