在构建过程中调用setState()或markNeedsBuild
class MyHome extends StatefulWidget { @override State<StatefulWidget> createState() => new MyHomePage2(); } class MyHomePage2 extends State<MyHome> { List items = new List(); buildlist(String s) { setState(() { print("entered buildlist" + s); List refresh = new List(); if (s == 'button0') { refresh = [ new Refreshments("Watermelon", 250), new Refreshments("Orange", 275), …