Checking a checkbox in listview makes other random checkboxes checked too

Question

whenever i check a checkbox in my listview , other random checkboxes get checked too . It could be due to item recycling by listview.

I also tried setting android:f

Answer 1

When a listview recycles views , it recycles its present state as well as listeners attached to it. In my example, if the checkbox was checked and has a onCheckedChangeListener set, both will remain a part of recycled view based on position. So it is our responsibility to reset all states and remove previous listeners.

So when I was unchecking the recycled view, the onCheckedChange listener was getting executed. one line made the program work perfectly. The listener was removed by :

holder.ckbox.setOnCheckedChangeListener(null); 

Below is the working code of Adapter for people who may stumble upon this problem:

public class MyCustomAdapter extends ArrayAdapter<ApplicationInfo>  {

private List<ApplicationInfo> appInfoList;
private LayoutInflater mInflater;
private PackageManager pm;
ArrayList<Boolean> positionArray;
private Context ctx;
int[] visiblePosArray;
private volatile int positionCheck; 

public MyCustomAdapter(Context context, List<ApplicationInfo> myList) {
    super(context, NO_SELECTION);
    appInfoList = myList;
    ctx=context;
    mInflater =     (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    pm = context.getPackageManager();

    positionArray = new ArrayList<Boolean>(myList.size());
    for(int i =0;i<myList.size();i++){
        positionArray.add(false);
    }
}
@Override
public int getCount() {
    // TODO Auto-generated method stub
    return appInfoList.size();
}

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

    View row = convertView;
    Holder holder = null;

    if(row==null){
        row = mInflater.inflate(R.layout.testlayout, null); 
        //  visiblePosArray[position%visiblePosArray.length]=position;
        holder = new Holder();
        holder.appIcon = (ImageView)row.findViewById(R.id.imageView1);

        holder.ckbox =(CheckBox)row.findViewById(R.id.checkBox1);

        row.setTag(holder);
    } else {

        holder = (Holder) convertView.getTag();
    holder.ckbox.setOnCheckedChangeListener(null);

    }

    holder.ckbox.setFocusable(false);
    holder.appIcon.setImageDrawable(appInfoList.get(position).loadIcon(pm));
    holder.ckbox.setChecked(positionArray.get(position));
    holder.ckbox.setText(appInfoList.get(position).loadLabel(pm));
    holder.ckbox.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if(isChecked ){
            System.out.println(position+"--- :)");
                positionArray.set(position, true);

            }else
                positionArray.set(position, false);
        }
    });

    return row;
}
static class Holder
{
    ImageView appIcon;
    CheckBox ckbox;

}

}

Answer 2

You need to keep track of the check state, because ListView re-uses the Views. so the state for position one which was previously enabled/disabled may appear as is for position 7.

So what you need to do is keep the checked state in an array boolean or whatever you prefer.

Take a class level boolean [] checkedState; initialize it in constructor, according to your data array size, you can use ArrayList<Boolean> too for dynamic size.

set OnStateChangeListener to your CheckBoxes in getView(), whenever it is checked or un-checked, take the position and save it in the array of checkedState like this:

checkedState[position] = false;// or true accordingly

and when setting other data for View like TextView or ImageView for any specific position, set the checked state also accordingly like this:

holder.appIcon.setImageDrawable(appInfoList.get(position).loadIcon(pm));
holder.ckbox.setChecked(checkedState[position]);

A very good explanation and example:

Android custom image gallery with checkbox in grid to select multiple

Edit: Actually what is happening is, you position is getting buggy, to solve this add these lines:

holder.ckbox.setText(appInfoList.get(position).loadLabel(pm));
holder.ckbox.setTag(String.valueOf(position));   // to properly track the actual position
holder.ckbox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
      @Override
      public void onCheckedChanged(CompoundButton v, boolean isChecked) {
            int pos = Integer.parseInt( v.getTag().toString()) ; //to take the actual position
            positionArray.add(pos, isChecked);  // we don't need to check whether it is true or false, however you can put if-else to debug the app.

      }
});

Answer 3

A combination of these two approaches worked for me:

I have a boolean array on class level which I use to keep track of the value of checkboxes.

boolean [] checkedItems = new boolean[listItems.size()];

In getView() :

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {

            convertView = inflater.inflate(R.layout.menu_item_list_item,
                    parent, false);

            holder = new ViewHolder();

            holder.name = (TextView) convertView
                    .findViewById(R.id.menuItemLargeName);
            holder.mainItemCheckBox = (CheckBox) convertView
                    .findViewById(R.id.menuItemLargeCheckBox);

            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
            // remove the listener so that it does not get attached to other chechboxes. 
            holder.mainItemCheckBox.setOnCheckedChangeListener(null);
            //update the checkbox value from boolean array
            holder.mainItemCheckBox.setChecked(checkedItems[position]);
        }


        holder.name.setText(listItems.get(position).getName());

        holder.mainItemCheckBox
                .setOnCheckedChangeListener(onCheckedListener);
        holder.mainItemCheckBox
                .setTag(R.id.menuItemLargeCheckBox, position);

        return (convertView);
    }

In my OnCheckedChangeListener() : update the boolean array.

    OnCheckedChangeListener onCheckedListener = new OnCheckedChangeListener() {

    @Override
    public void onCheckedChanged(CompoundButton buttonView,
            boolean isChecked) {

        int position = (Integer) buttonView
                .getTag(R.id.menuItemLargeCheckBox);

        MenuItemObject menuItem = listItems.get(position);

        if (isChecked) {

            cartItems.add(menuItem);
            checkedItems[position] = true;

        } else {

            cartItems.remove(menuItem);
            checkedItems[position] = false;
        }


    }
};