Question

My ListViewItems have delete buttons in them. From those button’s click events I want to show a confirmation dialog before deleting the item via it’s ID from the database. The ID is stored in the item’s ViewHolder.

How can I access the item’s ViewHolder from the AlertDialog’s click handler? Here is the relevant code. Compiler chokes on “V” inside onClick(DialogInterface dialog, int whichButton).

I could store the ID in the button’s tag but that feels awkward.

I’m targetting minimum API level 8 but let me know if higher API levels have a solution for this. It’s my first Android program so there may very well be an obvious solution.

private static class MyAdapter extends CursorAdapter {
//.....
    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        View view = View.inflate(context, R.layout.my_detail, null);
        MyViewHolder holder = new MyViewHolder();
        holder.deleteButton = (Button) view.findViewById(R.id.deleteButton);
        holder.deleteButton.setOnClickListener(deleteButtonClickListener);
        holder.editButton = (Button) view.findViewById(R.id.editButton);
        holder.editButton.setOnClickListener(editButtonClickListener);
        holder.nameTextView = (TextView) view
                .findViewById(R.id.nameTextView);
        holder.itemId = cursor.getLong(cursor
                .getColumnIndex(MyData.ID_COLUMN));
        view.setTag(holder);
        return view;
    } // newView()
//.....
    private OnClickListener deleteButtonClickListener = new OnClickListener() {

        public void onClick(View v) {
            new AlertDialog.Builder(_context)
                    .setTitle("Delete?")
                    .setMessage("Delete item?")
                    .setIcon(android.R.drawable.ic_dialog_alert)
                    .setPositiveButton(android.R.string.yes,
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog,
                                        int whichButton) {
                                    MyViewHolder holder = (MyViewHolder) ((View) v
                                            .getParent()).getTag();
                                    long itemId = holder.itemId;
                                    _MyData.deleteItem(itemId);
                                }
                            }).setNegativeButton(android.R.string.no, null)
                    .show();
        } // onClick()

    }; // deleteButtonClickListener
//.....
}

Answer 1

Your code actually looks pretty good, the only change needed is that v needs to be declared final, like so:

private OnClickListener deleteButtonClickListener = new OnClickListener()
{
    public void onClick(final View v) { }
}

The reason for this is due to how Java implements closures. v should be final so that our implementation of DialogInterface.OnClickListener in the setPositiveButton() has access to the variable.