在SingleChildScrollView下的MainAxisAlignment不工作。

Question

我开发了一个登录界面，在这个界面中，首先当我打开键盘时，我得到了render flex错误，所以我把我的widgets包在SingleChildScrollView中，但之后mainAxisAlignment of Column没有工作，但当我删除SingleChildScrollView时，除了render flex错误外，一切工作正常。

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class LoginScreenOne extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: SafeArea(
          child: Stack(
            children: [
              Container(
                height: double.infinity,
                width: double.infinity,
                color: Colors.blue,
              ),
              SingleChildScrollView(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Container(
                      width: double.infinity,
                      child: Padding(
                        padding: const EdgeInsets.only(top: 70, left: 20),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            Icon(
                              Icons.keyboard_arrow_up,
                              size: 30,
                              color: Colors.white,
                            ),
                            Text(
                              "Login Screen",
                              style: TextStyle(
                                  color: Colors.white,
                                  fontSize: 24,
                                  fontWeight: FontWeight.bold),
                            ),
                          ],
                        ),
                      ),
                    ),
                    Container(
                      width: double.infinity,
                      height: MediaQuery.of(context).size.height * 0.6,
                      decoration: BoxDecoration(
                        color: Colors.white,
                        borderRadius: BorderRadius.only(
                          topLeft: Radius.circular(30),
                          topRight: Radius.circular(30),
                        ),
                      ),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Padding(
                            padding: const EdgeInsets.only(top: 50, left: 20),
                            child: Text(
                              "Welcome",
                              style: TextStyle(
                                  fontWeight: FontWeight.bold, fontSize: 20),
                            ),
                          ),
                          Padding(
                            padding: const EdgeInsets.all(20),
                            child: TextField(
                              decoration: InputDecoration(
                                  icon: Icon(Icons.email),
                                  hintText: "Enter User Name"),
                            ),
                          ),
                          Padding(
                            padding: const EdgeInsets.all(20),
                            child: TextField(
                              obscureText: true,
                              decoration: InputDecoration(
                                  icon: Icon(Icons.vpn_key),
                                  hintText: "Enter Password"),
                            ),
                          ),
                          Padding(
                            padding: const EdgeInsets.all(20),
                            child: Container(
                              width: double.infinity,
                              height: 50,
                              child: FlatButton(
                                shape: RoundedRectangleBorder(
                                    borderRadius: BorderRadius.circular(15),
                                    side: BorderSide(width: 2, color: Colors.blue)),
                                textColor: Colors.blue,
                                child: Text(
                                  "Sign In",
                                  style: TextStyle(
                                      fontWeight: FontWeight.bold, fontSize: 16),
                                ),
                                onPressed: () {},
                              ),
                            ),
                          ),
                          Center(
                            child: Text(
                              "Forgot Password",
                              style: TextStyle(color: Colors.grey),
                            ),
                          ),
                          Padding(
                            padding: const EdgeInsets.all(20),
                            child: Container(
                              width: double.infinity,
                              height: 50,
                              child: FlatButton(
                                textColor: Colors.white,
                                shape: RoundedRectangleBorder(
                                    borderRadius: BorderRadius.circular(15)
                                ),
                                child: Text("Create Account"),
                                color: Colors.blue,
                                onPressed: () {},
                              ),
                            ),
                          )
                        ],
                      ),
                    )
                  ],
                ),
              ),
            ],
          ),
        ));
  }
}

Answer 1

是的，当你将 "Column "包裹在 "SingleChildScrollView "中时，"Column "的MainAxisAlignment "属性不工作。我不知道原因，但就是这样。

我使用'SizedBox(height: xx)'来给'Column'内的widget提供空间，当我绝对需要一个滚动视图时，否则我倾向于不使用'SingleChildScrollView'。