I have a PickerList, per default selectedIndex=-1, so the user is supposed to choose a value from the list.
When the user press a "Send" button, I need to validate wether the user has selected an option or not. If no option has been selected, I need to change the PickerList skin (actually just the Button sub-component) to inform the user about the error.
It's very similar to how TextInput works with TextInputState.ERROR, but Button has no ERROR state.
What would be the correct way to achieve this?
BTW, I am skinning the app with my first custom theme.