如何在顫振上使用導航器

我有這樣的頁面結構：

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'First App',
      theme: ThemeData(
        primaryColor: appPrimaryColour,
        scaffoldBackgroundColor: appBackGroupCoulour,
      ),
      home: const WelcomePage(),
    );

class WelcomePage extends StatelessWidget {
  const WelcomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: Body(),
    );
  }
}

歡迎頁面正文：

//Body for the welcome page
class Body extends StatelessWidget {
  const Body({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Background(
      child: SingleChildScrollView(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              "Welcome To My First App",
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            SizedBox(height: size.height * 0.05),
            SizedBox(height: size.height * 0.05),
            RoundedButton(
              text: "LOGIN",
              color: appPrimaryColour,
              onPressed: () => {
                Navigator.of(context).push(
                  MaterialPageRoute(
                    builder: (context) => const LoginPage(),
                  ),
                ),
              },
            ),
          ],
        ),
      ),
    );
  }
}

登錄頁面通過登錄頁面的正文小部件

class LoginPage extends StatelessWidget {
  const LoginPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: Body(),
    );
  }
}

登錄正文：

//Body for login
class Body extends StatelessWidget {
  const Body({
    Key? key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Background(
      child: SingleChildScrollView(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              "LOGIN",
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            SizedBox(height: size.height * 0.03),
            RoundedInputField(
              hintText: "Enter email address",
              icon: const Icon(
                Icons.email,
              ),
              labelText: "Email",
              onChanged: (value) {},
            ),
            RoundedPasswordField(
              hintText: "Enter password",
              labelText: "Password",
              icon: const Icon(
                Icons.lock,
              ),
              suffixIcon: const Icon(
                Icons.visibility,
                color: appPrimaryColour,
              ),
              onChanged: (value) {},
            ),
            RoundedButton(
              text: "LOGIN",
              onPressed: () {},
            ),
            SizedBox(height: size.height * 0.03),
            AlreadyHaveAnAccountCheck(
              onTaped: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (context) => const SignUpPage(),
                  ),
                );
              },
            ),
          ],
        ),
      ),
    );
  }
}

這是一個可重用的小部件，用于顯示背景影像或任何其他內容：

class Background extends StatelessWidget {
  final Widget child;
  const Background({
    Key? key,
    required this.child,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Container(
      height: size.height,
      width: double.infinity,
      child: Stack(
        alignment: Alignment.center,
        children: <Widget>[
          child,
        ],
      ),
    );
  }
}

class RoundedButton extends StatelessWidget {
  final String text;
  final Function onPressed;
  final Color color, textColor;

  const RoundedButton({
    Key? key,
    required this.text,
    required this.onPressed,
    this.color = appPrimaryColour,
    this.textColor = Colors.white,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    var size = MediaQuery.of(context).size;
    return Container(
      margin: const EdgeInsets.symmetric(vertical: 10),
      width: size.width * 0.8,
      child: ClipRRect(
        borderRadius: BorderRadius.circular(30),
        child: newElevatedButton(),
      ),
    );
  }

  //Used:ElevatedButton as FlatButton is deprecated.
  //Here we have to apply customizations to Button by inheriting the styleFrom

  Widget newElevatedButton() {
    return ElevatedButton(
      child: Text(
        text,
        style: TextStyle(color: textColor),
      ),
      onPressed: () => onPressed,
      style: ElevatedButton.styleFrom(
          primary: color,
          padding: const EdgeInsets.symmetric(horizontal: 40, vertical: 20),
          textStyle: TextStyle(
              color: textColor, fontSize: 14, fontWeight: FontWeight.w500)),
    );
  }
}

嘗試導航到登錄頁面時，沒有任何反應。有人可以幫我嗎？我現在已經沒有想法了，我現在看了太多教程。

uj5u.com熱心網友回復：

你正在onPressed: () => onPressed做newElevatedButton()。它正在創建另一個匿名方法，但在其中，您沒有呼叫onPressed().

你可以做

 onPressed: onPressed,

或者

onPressed: () => onPressed()

標籤：扑 镖

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