flutter登录界面设计，，让人茅塞顿开

在Flutter中设计一个引人入胜的登录界面可以通过组合各种widgets来实现。以下是一个简单的登录界面设计示例：

import 'package:flutter/material.dart';
 
class LoginPage extends StatefulWidget {
  @override
  _LoginPageState createState() => _LoginPageState();
}
 
class _LoginPageState extends State<LoginPage> {
  final _formKey = GlobalKey<FormState>();
  String _email, _password;
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SingleChildScrollView(
          child: Padding(
            padding: const EdgeInsets.all(24.0),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                Image.asset(
                  'assets/logo.png',
                  height: 100.0,
                ),
                SizedBox(height: 48.0),
                Form(
                  key: _formKey,
                  child: Column(
                    children: <Widget>[
                      TextFormField(
                        decoration: InputDecoration(
                          labelText: 'Email',
                        ),
                        validator: (value) {
                          if (value.isEmpty) return 'Email is required';
                          if (!value.contains('@')) return 'Invalid email';
                          return null;
                        },
                        onSaved: (value) => _email = value,
                      ),
                      SizedBox(height: 12.0),
                      TextFormField(
                        decoration: InputDecoration(
                          labelText: 'Password',
                        ),
                        obscureText: true,
                        validator: (value) {
                          if (value.isEmpty) return 'Password is required';
                          return null;
                        },
                        onSaved: (value) => _password = value,
                      ),
                      SizedBox(height: 12.0),
                      RaisedButton(
                        child: Text('Login'),
                        onPressed: () {
                          if (_formKey.currentState.validate()) {
                            _formKey.currentState.save();