Why do I get IllegalStateException with FocusRequester not being initialized in my Dialog on TV android app?

Question

So I have an app for both mobile and TV and on firebase I got error on crashlytics - Fatal Exception: java.lang.IllegalStateException FocusRequester is not initialized. Here are some possible fixes: 1. Remember the FocusRequester: val focusRequester = remember { FocusRequester() } 2. Did you forget to add a Modifier.focusRequester() ? 3. Are you attempting to request focus during composition? Focus requests should be made in response to some event. Eg Modifier.clickable { focusRequester.requestFocus() }. I don't know what I'm doing wrong

val buttonFocusRequester = remember { FocusRequester() }
var isItemInFocus by remember { mutableStateOf(false) }

Surface(
    modifier = modifier,
    color = MaterialTheme.colorScheme.primary,
) {
    val tvModifier =
        if (isTV) {
            Modifier
                .onFocusChanged { isItemInFocus = it.isFocused }
                .focusRequester(buttonFocusRequester)
        } else {
            Modifier
        }
    LaunchedEffect(Unit) {
        if(isTV) {
            buttonFocusRequester.requestFocus()
        }
    }

Answer 1

LaunchedEffect might run before the item has a chance to be placed on the screen. You can have a boolean flag that tracks whether the button is placed and then request focus.

var isPlaced by remember { mutableStateOf(false) }

val tvModifier = 
        if (isTV) {
            Modifier
                .onPlaced { isPlaced = true }
                .focusRequester(buttonFocusRequester)
        } else {
            Modifier
        }

LaunchedEffect(isPlaced) {
    if(isTV && isPlaced) {
        buttonFocusRequester.requestFocus()
    }
}