试图转换TextFormField

Question

我试图将TextEditingController转换为int，因为我希望通过使用TextEditingController从数据库中删除用户ID。

看一下：(<

这是我的密码：

import 'package:flutter/material.dart';
        import 'package:untitled/database.dart';
        import './model/columns.dart';
        import './database.dart';
        
        void main() {
          WidgetsFlutterBinding.ensureInitialized();
          runApp(MyApp());
        }
        
        class MyApp extends StatefulWidget {
          @override
          _MyAppState createState() => _MyAppState();
        }
        class _MyAppState extends State<MyApp> {
        
          @override
          void dispose() {
            textController.dispose();
            super.dispose();
          }
        
          final textController = TextEditingController();
          int? selectedId;
        
          @override
          Widget build(BuildContext context) {
            return MaterialApp(
              home: Scaffold(
                  appBar: AppBar(
                    title: Text("App"),
                  ),
                  body: Form(
                    child: Column(
                      children: [
                        Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: TextField(
                            controller: textController,
                            decoration: InputDecoration(
                                labelText: "Insert row",
                                border: OutlineInputBorder(
                                    borderRadius: BorderRadius.circular(25))),
                          ),
                        ),
                        ElevatedButton(
                          child: Icon(Icons.save),
                          onPressed: () async {
                            await DatabaseHelper.instance
                                .insert(Users(name: textController.text));
                            setState(() {
                              textController.clear();
                            });
                            print("Inserted!");
                          },
                        ),
        
                        Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: TextFormField(
                            //controller: selectedId, // <-------
                            decoration: InputDecoration(
                                labelText: "Delete ID",
                                border: OutlineInputBorder(
                                    borderRadius: BorderRadius.circular(25))),
                            keyboardType: TextInputType.number,
                          ),
                        ),
                        ElevatedButton(
                          child: Icon(Icons.delete),
                          onPressed: () async {
                            DatabaseHelper.instance.delete(selectedId!); // <-------
                          },
                        ),
                        ElevatedButton(
                          child: Text("Check all rows"),
                          onPressed: () async {
                            print(await DatabaseHelper.instance.queryAll());
                          },
                        ),
                      ],
                    ),
                  )),
            );
          }
        }

Answer 1

创建另一个控制器，然后通过与int.parse(yourcontroller.text)进行转换，将输入的数据作为int传递

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final textController = TextEditingController();
  final numberController = TextEditingController();

  @override
  void dispose() {
    textController.dispose();
    numberController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Padding(
              padding: const EdgeInsets.all(8.0),
              child: TextFormField(
                controller: numberController,
                decoration: InputDecoration(
                    labelText: "Delete ID",
                    border: OutlineInputBorder(
                        borderRadius: BorderRadius.circular(25))),
                keyboardType: TextInputType.number,
              ),
            ),
            ElevatedButton(
              child: Icon(Icons.delete),
              onPressed: () async {
             DatabaseHelper.instance.delete(int.parse(numberController.text)); 
                print(int.parse(numberController.text));
              },
            ),
          ],
        ),
      ),
    );
  }
}