Flutter

Question

我刚接触 Flutter 一个月。目前我面临以下显示未定义名称 'context' 的问题。我已按照建议导入 'dart:js'，但它显示错误“参数类型 'JsObject' 无法分配给参数类型 'BuildContext'。”

import 'package:dparking/reusable_widgets/reusable_widget.dart';
import 'package:dparking/screens/signup_screen.dart';
import 'package:flutter/material.dart';

class SignInScreen extends StatefulWidget {
  const SignInScreen({Key? key}) : super(key: key);

  @override
  State<SignInScreen> createState() => _SignInScreenState();
}

class _SignInScreenState extends State<SignInScreen> {
  final TextEditingController _passwordTextController = TextEditingController();
  final TextEditingController _emailTextController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        decoration: const BoxDecoration(
            gradient: LinearGradient(colors: [
          Colors.blue,
          Colors.green,
        ], begin: Alignment.topCenter, end: Alignment.bottomCenter)),
        child: SingleChildScrollView(
          child: Padding(
            padding: EdgeInsets.fromLTRB(
                20, MediaQuery.of(context).size.height * 0.2, 20, 0),
            child: Column(
              children: <Widget>[
                logoWidget("assets/images/DParking.png"),
                const SizedBox(
                  height: 30,
                ),
                reusableTextField("Enter UserName", Icons.person_outline, false,
                    _emailTextController),
                const SizedBox(
                  height: 20,
                ),
                reusableTextField("Enter Password", Icons.lock_outline, true,
                    _passwordTextController),
                const SizedBox(
                  height: 20,
                ),
                signInSignUpButton(context, true, () {}),
                signUpOption()
              ],
            ),
          ),
        ),
      ),
    );
  }
}

Row signUpOption() {
  return Row(
    mainAxisAlignment: MainAxisAlignment.center,
    children: [
      const Text("Don't have account?",
          style: TextStyle(color: Colors.white70)),
      GestureDetector(
        onTap: () {
          Navigator.push(context, //<- error on this line
              MaterialPageRoute(builder: (context) => SignUpScreen()));
        },
        child: const Text(
          " Sign Up",
          style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
        ),
      )
    ],
  );
}

请给我一些关于如何解决这个问题的建议。谢谢。

Answer 1

您应该将 context 作为 signUpOption 参数传递。

  
    signUpOption(context)
  ],
...

Row signUpOption(BuildContext context) {
  ...
}

或将函数移动到 _SignInScreenState class 以使用 State 的 context。

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