Flutter：在 StatefulBuilder 的 AlertDialog 上使用 OK 按钮设置全局变量

Question

How to set global variable using OK button on AlertDialog in StatefulBuilder?

String stringMain = "My String";

 Future<String?> dialogChangeMainContent(BuildContext context) { return showDialog<String>( context: context, builder: (BuildContext context) { return StatefulBuilder(builder: (context, setState) { return AlertDialog( title: const Text('AlertDialog Title'), content: const Text('AlertDialog description'), actions: <Widget>[ TextButton( onPressed: () { Navigator.pop(context, 'OK'); setState(() { // setState2(); stringMain = "New String"; }); }, child: const Text('OK'), ), ], ); }); }); }

I changed StatefulWidget from StatelessWidget, but nothing changes. What I know is the problem is because the button is in the StatefulBuilder. If using BLoC etc, it's too wasteful for only small applications.

Answer 1

I found a way to solve my problem, redrawing (refreshing) the Text (or other widget) in a Stateless Widget from an AlertDialog in a StatefulBuilder. By creating a setState with a different name , for example setStateTarget . Without having to rebuild the entire page, or without state management like BLoC. My code:

String stringMain = "My String";

 @override Widget build(BuildContext context) { return Column( //.... children: [ StatefulBuilder(builder: (BuildContext context, setStateTarget) { return Column(children: [ Text(stringMain), // <--- target TextButton( onPressed: () => dialogChangeMainContent(context, setStateTarget), child: const Text('Show Dialog')) ]); }) ], ); } Future<String?> dialogChangeMainContent(BuildContext context, StateSetter setStateTarget) { return showDialog<String>( context: context, builder: (BuildContext context) { return StatefulBuilder(builder: (context, setState) { return AlertDialog( title: const Text('AlertDialog Title'), content: const Text('AlertDialog description'), actions: <Widget>[ TextButton( onPressed: () { Navigator.pop(context, 'OK'); setStateTarget(() { // setState2(); stringMain = "New String"; }); }, child: const Text('OK'), ), ], ); }); }); }