Question

I have an unusual issue with my ListView. I currently have a “deselectAll()” method which iterates through the items in my ListView and sets them to unchecked (the items implement the Checkable interface). The “checked” variable gets changed correctly (the view reports as not being checked), but the visual indicator (in this case, a background change) does not show the view as unchecked (the background stays the color of a checked item).

I am iterating and deselecting through my listview like so (I also added my declerations):

private ListView vw_entryList;

private void deselectAll() {
    for (int i = 0; i < sAdapter.getCount(); i++) {
        ((Entry)vw_entryList.getItemAtPosition(i)).setChecked(false);
    }
}

The code for my implemented setChecked() is as follows:

public void setChecked(boolean checked) {
    _checked = checked;
    if (checked) {
        setBackgroundResource(R.drawable.listview_checked);
    }
    else  {
        setBackgroundResource(R.drawable.listview_unchecked);
    }
    invalidate();
}

It should be noted that when the items are clicked, they are toggled between checked and unchecked in the OnItemClickListener, and this works ok, with the background change and everything. The code for toggling is very similar:

public void toggle() {
    _checked = !_checked;
    setBackgroundResource(_checked ? 
            R.drawable.listview_checked : R.drawable.listview_unchecked);
    invalidate();
}

The only difference I can see is where the methods are called from. toggle() is called from within the OnItemClickListener.onClick() method, while my deselectAll() is called from within a button’s standard OnClickListener, both in the same class. Does anyone have any ideas as to why the background doesn’t change when I call my deselectAll() function?

Answer 1

After trying everything (thanks for your help Jarek), I found a solution that works for my purposes. Instead of implicitly calling the setChecked() within the view that was clicked, I leave it up to the setItemChecked() method within the ListView class.

My updated code:

private void deselectAll() {        
    for (int i = 0; i < sAdapter.getCount(); i++) {
        vw_entryList.setItemChecked(i, false);
    }
}

My best guess is that the ListView knows that its items implement the Checkable class, and thus requires itself to be the handler of all item operations. Something along those lines. If anyone can explain in more detail why this solution works while the others did not, I’ll reward them with the answer and an upvote.