选择列表视图项目，将值放入表单域，然后关闭列表视图- Flutter

import 'package:flutter/material.dart';

class MyForm extends StatefulWidget {
  @override
  _MyFormState createState() => _MyFormState();
}

class _MyFormState extends State<MyForm> {
  String selectedValue;

  List<String> items = ['Item 1', 'Item 2', 'Item 3'];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Form Example'),
      ),
      body: ListView.builder(
        itemCount: items.length,
        itemBuilder: (BuildContext context, int index) {
          return ListTile(
            title: Text(items[index]),
            onTap: () {
              setState(() {
                selectedValue = items[index];
              });
              Navigator.pop(context);
            },
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          showDialog(
            context: context,
            builder: (BuildContext context) {
              return AlertDialog(
                title: Text('Selected Value'),
                content: Text(selectedValue ?? 'No value selected'),
                actions: [
                  TextButton(
                    child: Text('Close'),
                    onPressed: () {
                      Navigator.pop(context);
                    },
                  ),
                ],
              );
            },
          );
        },
        child: Icon(Icons.check),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: MyForm(),
  ));
}