예시
방법
Future.delayed(Duration(milliseconds: 1000)).then((_) {
showModalBottomSheet(
context: context,
isScrollControlled: true,
backgroundColor: Colors.transparent,
builder: (context) => Container(
height: MediaQuery.of(context).size.height * 0.75,
decoration: new BoxDecoration(
color: Colors.white,
borderRadius: new BorderRadius.only(
topLeft: const Radius.circular(25.0),
topRight: const Radius.circular(25.0),
),
),
child: Center(
child: Text("Modal content goes here"),
),
),
);
});
참고
https://stackoverflow.com/a/60072706