checkbox in List being checked unexpectedly

Question

I have list of checkboxes in list binded by Custom simpleCursorAdapter. In my custom simpleCursorAdapter, I've overridden newView and bindView with my modifications. I've managed somehow to do multichoice. The wierd thing is, after I delete any item from my list, the first item's checkbox is being checked all of a sudden. How does that happen? How can I solve it?

My SimpleCursorAdapter class:

public class MyListCursorAdapter extends SimpleCursorAdapter
{
    private Context context;
    private int layout;

    public MyCursorAdapter(Context context, int layout, Cursor c,
            String[] from, int[] to)
    {
        super(context, layout, c, from, to);
        this.context = context;
        this.layout = layout;
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent)
    {
        Cursor c = getCursor();
        final LayoutInflater inflater = LayoutInflater.from(context);
        View v = inflater.inflate(layout, parent, false);
        CheckBox chkBoxBtn = (CheckBox) v.findViewById (R.id.deleteTwittChkBox);
        if (chkBoxBtn != null)
        {
            chkBoxBtn.setChecked(false);
        }
        return v;
    }

    @Override
    public void bindView(View v, Context context, Cursor c)
    {
        --binding view to my textsview in my items
        //now it's the importat part:
            CheckBox chkBoxBtn = (CheckBox) v.findViewById(R.id.deleteTwittChkBox);
    if (chkBoxBtn != null)
    {
        chkBoxBtn.setId(Integer.valueOf(c.getString(c
                .getColumnIndex(MyUsers.User._ID))));
        chkBoxBtn.setOnClickListener(new OnItemClickListener(chkBoxBtn, v));
        chkBoxBtn.setChecked(false);
    }
    }

    //i couldnt find another way of doing this, but this is how i set listeners to my checkboxses
    static ArrayList<String> checkedItemsList = new ArrayList<String>();

    private class OnItemClickListener implements OnClickListener
    {
        private int mPosition;
        private CheckBox chkBox;
        OnItemClickListener(CheckBox mChkBox, View v)
        {
            chkBox = mChkBox;
            chkBox.setChecked(false);
        }

        @Override
        public void onClick(View v)
        {
            if (chkBox.isChecked())
            {
                checkedItemsList.add(String.valueOf(chkBox.getId()));
            }
            else
            {
                checkedItemsList.remove(String.valueOf(chkBox.getId()));
            }
        }
    }
}

Here is the code part from the ListActivity class which describes the button that deletes the checked box items:

OnClickListener btListener = new OnClickListener()
{
    public void onClick(View view)
    {
        // long[] items = listView.getCheckItemIds();
        int x = 0;
        Uri myUri = Uri
        .parse("content://com.idan.datastorageprovider/users");
        String where = "_id" + "=?";
        //here i am tatking all checkboxes which ive added from the  adapter class
        ArrayList<String> checkedItemsList =   MySimpleCursorAdapter.checkedItemsList;
        for (String itemID : checkedItemsList)
        {
            getContentResolver()
            .delete(myUri, where, new String[] { itemID});
            checkedItemsList.remove(itemID);
        }
    }
};

Answer 1

I doubt that SimpleCursorAdapter is the right class to extend here.

Is the "checked" state connected to the data XML in any way? No? So you need your own custom adapter!

Basically all adapters have to implement a way to generate a view from a given element (more precisely an element position!). This will be called at any time where the list wants to display an element. Now, the trick it uses is to re-use formerly created list view elements that cannot be seen on screen any more! Thus: when you scroll your list down and an element disappears at the top, EXACTLY this view object will be re-used for the next appearing item.

So, when this method is called with a given "old" view that should be re-used, all contained elements will have to be set according the elements data. If a checkbox is part of this game, you will have to have a storage for the checked state! It is not sufficient to have a checkbox as there will be less checkbox objects as there are list elements!

SimpleCursorAdapters are there to - yeah - represent SIMPLE things. An XML describing data (images and text, as the documentation states). Because of this simplicity all you have to do here is provide a method to create NEW element view objects - you are not intercepting the re-use process AT ALL! It basically only knows how to put the data into an existing view object - but it is lacking the knowledge of how to handle checked/unchecked boxes!

Your solution: write your own BaseAdapter extension and do what has to be done: implement "getView" (and some other methods like getItem, getItemId and getCount). It's not hard at all! This API Demo uses a BaseAdapter and the mExpanded state here is basically identical to your checkbox states!

Good luck!

Answer 2

You might need to call notifyDataSetChanged when you modify the data.

Answer 3

The problem is probably that you're calling setChecked from within the onItemClickListener. One hacky way around this is to do the following before and after you call setChecked from within your listener:

chkBox.setClickable(false);
chkBox.setChecked(false);
checkBox.setClickable(true);

This will prevent your onItemClickListener from getting called when you manually call setChecked.