ensureGlobalTapCatcher method
Adds a TapOutsideHandler to the game if it doesn't already exist.
Implementation
Future<TapOutsideHandler> ensureGlobalTapCatcher() async {
if (children.query<TapOutsideHandler>().isEmpty) {
await add(TapOutsideHandler());
}
return lifecycleEventsProcessed.then((_) {
return children.query<TapOutsideHandler>().first;
});
}