flutter - Flutter：如何在 AlertDialog 中通过 TextFormField 更改变量？

Answer 1

I would use ValueNotifier for this. But first you need to add a controller to your TextFormField so you can get the text user typed in.

//initialize it
final myController = TextEditingController();

TextFormField(
  controller: myController, //pass it to the TextFormField
),

TextButton(
  child: new Text("ok"),
  onPressed: () {
    String input = myController.text; //this is how you get the text input
    _formKey.currentState?.save();
    Navigator.of(context).pop();
  },
),

As I said you also need to initialize ValueNotifier and pass it to _showMessageDialog

ValueNotifier<int> money = ValueNotifier(0);
_showMessageDialog(money); //and pass it to your function

void _showMessageDialog(ValueNotifier<int> money) {
  TextButton(
    child: new Text("ok"),
    onPressed: () {
      String input = myController.text; //this is how you get the text input
      money.value = int.parse(input); //and then update your money variable
      _formKey.currentState?.save();
      Navigator.of(context).pop();
    },
  ),
}