Jahangir Alam's questions

我遇到了错误：texteditingcontroller 在被释放后被使用。一旦您在 TextEditingController 上调用 dispose()，它就不能再使用了。

我第一次浏览该页面时没有遇到此错误，但当我返回并尝试第二次转到同一屏幕时遇到了此错误。

这是我的 2 屏代码，包括命名的循环代码。最后我还将包含完整代码的 git 链接。

登录屏幕

    import 'package:batch8_taskmanager_project/ui/screens/sign_up_screen.dart';
import 'package:batch8_taskmanager_project/ui/widgets/screen_background.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

class SignInScreen extends StatefulWidget {
  const SignInScreen({super.key});

  static const String name = '/sign-in-screen';

  @override
  State<SignInScreen> createState() => _SignInScreenState();
}
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
final TextEditingController _emailTEController = TextEditingController();
final TextEditingController _passwordTEController = TextEditingController();

class _SignInScreenState extends State<SignInScreen> {
  @override
  Widget build(BuildContext context) {
    final textStyle = Theme.of(context).textTheme;

    return Scaffold(
      resizeToAvoidBottomInset: false,
      body: ScreenBackground(
          child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: [
              const SizedBox(
                height: 68,
              ),
              Text(
                "Get Started With",
                style: textStyle.titleLarge,
              ),
              const SizedBox(
                height: 24,
              ),
              TextFormField(
                controller: _emailTEController,
                keyboardType: TextInputType.emailAddress,
                decoration: const InputDecoration(hintText: "Email Address"),
              ),
              const SizedBox(
                height: 24,
              ),
              TextFormField(
                controller: _passwordTEController,
                obscureText: true,
                decoration: const InputDecoration(hintText: "Password"),
              ),
              const SizedBox(
                height: 24,
              ),
              ElevatedButton(onPressed: () {}, child: const Icon(Icons.double_arrow)),
              const SizedBox(
                height: 48,
              ),
              TextButton(onPressed: () {}, child: const Text("Forgot Password?")),
              const SizedBox(
                height: 24,
              ),
              _buildSignIn()
            ],
          ),
        ),
      )),
    );
  }

  Widget _buildSignIn() {
    return RichText(
            text: TextSpan(
                text: "Don't have an account? ",
                style: const TextStyle(color: Colors.grey),
                children: [
                  TextSpan(
                      text: "Sign up",
                      style: const TextStyle(
                          color: Colors.green, fontWeight: FontWeight.bold),
                      recognizer: TapGestureRecognizer()..onTap = () {
                        Navigator.pushNamed(context, SignupScreen.name);
                      })
                ]),
          );
  }

  @override
  void dispose() {

      _emailTEController.dispose();
      _passwordTEController.dispose();

    super.dispose();
  }
}

注册屏幕

    import 'package:batch8_taskmanager_project/ui/widgets/screen_background.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

class SignupScreen extends StatefulWidget {
  const SignupScreen({super.key});

  static const String name = '/sign-up-screen';

  @override
  State<SignupScreen> createState() => _SignupScreenState();
}
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
final TextEditingController _emailTEController = TextEditingController();
final TextEditingController _firstNameTEController = TextEditingController();
final TextEditingController _lastNameTEController = TextEditingController();
final TextEditingController _mobileTEController = TextEditingController();
final TextEditingController _passwordTEController = TextEditingController();

class _SignupScreenState extends State<SignupScreen> {
  @override
  Widget build(BuildContext context) {
    final textStyle = Theme.of(context).textTheme;

    return Scaffold(
      resizeToAvoidBottomInset: false,
      body: ScreenBackground(
          child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: [
              const SizedBox(
                height: 68,
              ),
              Text(
                "Join with Us",
                style: textStyle.titleLarge,
              ),
              const SizedBox(
                height: 24,
              ),
              TextFormField(
                controller: _emailTEController,
                keyboardType: TextInputType.emailAddress,
                decoration: const InputDecoration(hintText: "Email Address"),
              ),
              const SizedBox(
                height: 12,
              ),
              TextFormField(
                controller: _firstNameTEController,

                decoration: const InputDecoration(hintText: "First Name"),
              ),
              const SizedBox(
                height: 12,
              ),
              TextFormField(
                controller: _lastNameTEController,

                decoration: const InputDecoration(hintText: "Last Name"),
              ),
              const SizedBox(
                height: 12,
              ),
              TextFormField(
                controller: _mobileTEController,
                keyboardType: TextInputType.number,
                decoration: const InputDecoration(hintText: "Mobile"),
              ),
              const SizedBox(
                height: 12,
              ),
              TextFormField(
                controller: _passwordTEController,
                obscureText: true,
                decoration: const InputDecoration(hintText: "Password"),
              ),
              const SizedBox(
                height: 24,
              ),
              ElevatedButton(onPressed: () {}, child: const Icon(Icons.double_arrow)),
              const SizedBox(
                height: 48,
              ),
              _buildSignUp()
            ],
          ),
        ),
      )),
    );
  }

  Widget _buildSignUp() {
    return RichText(
            text: TextSpan(
                text: "Have an account? ",
                style: const TextStyle(color: Colors.grey),
                children: [
                  TextSpan(
                      text: "Sign in",
                      style: const TextStyle(
                          color: Colors.green, fontWeight: FontWeight.bold),
                      recognizer: TapGestureRecognizer()..onTap = () {
                        Navigator.pop(context);
                      })
                ]),
          );
  }

  @override
  void dispose() {
      _emailTEController.dispose();
      _firstNameTEController.dispose();
      _lastNameTEController.dispose();
      _mobileTEController.dispose();
      _passwordTEController.dispose();

    super.dispose();
  }
}

命名路由代码

initialRoute: '/',
  onGenerateRoute: (RouteSettings settings){
    late Widget widget;
    if(settings.name == SplashScreen.name){
      widget = const SplashScreen();
    }else if(settings.name == SignInScreen.name){
      widget = const SignInScreen();
    }else if(settings.name == SignupScreen.name){
      widget = const SignupScreen();
    }

    return MaterialPageRoute(builder: (_) => widget);
  },

https://github.com/jahangirsim/batch8_taskmanager_project.git

我想用 1 替换整数的第一个数字，用 0 替换接下来的 4/5 个数字。第一个数字没有变化，为 0。

例如，

1. 我从后端获取了 8123456789，但我想将其显示为 1000056789。
2. 我得到了 9665789456789 但我想将其显示为 1000009456789。

想要按照某种逻辑来决定改变数字（字符）的次数，比如，如果用户从 A 开始，那么想要改变前 6 个数字，或者如果用户从 B 开始，那么想要改变前 5 个数字。