Can't set checkbox state in onPrepareDialog

Question

I've got a dialog which shows a list of checkboxes. The info which boxes should be checked each time it opens comes from an edittext. I searched for a way to not allow caching of the dialog but couldn't find out how to do that. Now I override onPrepareDialog to set the checkboxes before the dialog opens. I deleted the content of my edittext, opened the dialog and there were still the same boxes checked... can anyone tell me how to reset the checkboxes?

    @Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        ListView lv = ((AlertDialog) dialog).getListView();

        if (lv == null)
            return;

        boolean[] checked = cbDialog.setAndGetCheckedArray();

        String s = "onPrepareDialog... checked=";
        for (int i=0; i<checked.length; i++)
            s+="["+i+"="+checked[i]+"]";
        System.out.println(s);

            // if edittext is empty, all entries in checked[] are false here,
            // but these changes do NOT affect the checkboxes in the dialog:
        for (int i=0; i<checked.length; i++)
            if (checked[i])
                lv.setItemChecked(i, true);
            else 
                lv.setItemChecked(i, false);
    }

Answer 1

Well, I finally found out how to solve this problem, perhaps it may help anyone:

I've found out that (because of the internal caching mechanism) it may be better not to call showDialog() in the activity and use onCreateDialog() to create a dialog, if the content of the dialog is modified dynamically.

Instead, I've created a class which extends AlertDialog.Builder. I implemented a method like "showCustomDialog()" where I call .setTitle..., .setMultiChoiceItems(), and finally show(). This method of my custom AlertDialog.Builder I can use in my activity and everything works as expected ;)

Answer 2

It seems that there is a general consensus that managed dialogs ('showDialog', 'onCreateDialog' etc.) should be avoided if the content needs to be changed for different instances. In particular, 'onPrepareDialog' in either the pre or post API Level 1.8 form serves no useful purpose.

Another example is: Question 954726