android - Flutter 滚动问题 - RenderFlex 底部溢出 192 像素

Question

我正在构建一个包含 4-5 个表单字段的表单。但是，当我尝试输入数据时，它会抛出以下错误

Performing hot reload...
Syncing files to device sdk gphone x86 64...
Reloaded 3 of 512 libraries in 363ms.
W/IInputConnectionWrapper(21437): getTextBeforeCursor on inactive InputConnection
W/IInputConnectionWrapper(21437): getSelectedText on inactive InputConnection
W/IInputConnectionWrapper(21437): getTextAfterCursor on inactive InputConnection
W/IInputConnectionWrapper(21437): beginBatchEdit on inactive InputConnection
W/IInputConnectionWrapper(21437): endBatchEdit on inactive InputConnection

════════ Exception caught by rendering library ═════════════════════════════════════════════════════
The following assertion was thrown during layout:
A RenderFlex overflowed by 192 pixels on the bottom.

The relevant error-causing widget was: 
  Column file:///C:/Users/xyz/Documents/quizmaker/lib/views/signup.dart:54:20
The overflowing RenderFlex has an orientation of Axis.vertical.
The edge of the RenderFlex that is overflowing has been marked in the rendering with a yellow and black striped pattern. This is usually caused by the contents being too big for the RenderFlex.

Consider applying a flex factor (e.g. using an Expanded widget) to force the children of the RenderFlex to fit within the available space instead of being sized to their natural size.
This is considered an error condition because it indicates that there is content that cannot be seen. If the content is legitimately bigger than the available space, consider clipping it with a ClipRect widget before putting it in the flex, or using a scrollable container rather than a Flex, like a ListView.

The specific RenderFlex in question is: RenderFlex#322a5 relayoutBoundary=up2 OVERFLOWING
...  needs compositing
...  parentData: offset=Offset(24.0, 0.0) (can use size)
...  constraints: BoxConstraints(0.0<=w<=363.4, 0.0<=h<=321.1)
...  size: Size(363.4, 321.1)
...  direction: vertical
...  mainAxisAlignment: start
...  mainAxisSize: min
...  crossAxisAlignment: start
...  textDirection: ltr
...  verticalDirection: down
◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤
════════════════════════════════════════════════════════════════════════════════════════════════════

这是我的代码

import 'package:flutter/material.dart';
import 'package:quizmaker/services/auth.dart';
import 'package:quizmaker/views/home.dart';
import 'package:quizmaker/views/signin.dart';
import 'package:quizmaker/widgets/widgets.dart';

class SignUp extends StatefulWidget {
  @override
  _SignUpState createState() => _SignUpState();
}

class _SignUpState extends State<SignUp> {

  final _formKey = GlobalKey<FormState>();
  String sName, fName, lName, email, phone, password;
  AuthService authService = new AuthService();
  bool _isLoading = false;

  signUp() async {
    if(_formKey.currentState.validate()){
      setState(() {
        _isLoading = true;
      });
      authService.signUpWithEmailAndPass(email, password).then((value){
        if(value != null){
          setState(() {
            _isLoading = false;
          });
          Navigator.pushReplacement(context, MaterialPageRoute(
            builder: (context) => Home()
          ));
        }
        });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: appBar(context),
        centerTitle: true,
        backgroundColor: Colors.transparent,
        elevation: 0.0,
        brightness: Brightness.light,
      ),
      body: _isLoading ? Container(
        child: Center(child: CircularProgressIndicator(),),
      ) : Form(
        key: _formKey,
        child: Container(
          padding: EdgeInsets.symmetric(horizontal: 24),
          child: Container(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
              Spacer(),
              TextFormField(
                validator: (val){
                  return val.isEmpty ? "Enter School Name" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "School Name"
                ),
                onChanged:  (val){
                  sName = val;
                },
              ),
              SizedBox(height: 6,),
              TextFormField(
                validator: (val){
                  return val.isEmpty ? "Enter First Name" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "First Name"
                ),
                onChanged:  (val){
                  fName = val;
                },
              ),
              SizedBox(height: 6,),
              TextFormField(
                validator: (val){
                  return val.isEmpty ? "Enter Last Name" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "Last Name"
                ),
                onChanged:  (val){
                  lName = val;
                },
              ),
              SizedBox(height: 6,),
              TextFormField(
                validator: (val){
                  return val.isEmpty ? "Enter Emailid" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "Email"
                ),
                onChanged:  (val){
                  email = val;
                },
              ),
              SizedBox(height: 6,),
              TextFormField(
                validator: (val){
                  return val.isEmpty ? "Enter Phone Number" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "Phone"
                ),
                onChanged:  (val){
                  phone = val;
                },
              ),
              SizedBox(height: 6,),
              TextFormField(
                obscureText: true,
                validator: (val){
                  return val.isEmpty ? "Enter Password" : null ;
                } ,
                decoration: InputDecoration(
                    hintText: "Password"
                ),
                onChanged:  (val){
                  password = val;
                },
              ),
              SizedBox(height: 24,),
              GestureDetector(
                onTap: (){
                  signUp();
                },
                child: Container(
                  padding: EdgeInsets.symmetric(vertical: 18),
                  decoration: BoxDecoration(
                      color: Colors.blue,
                      borderRadius: BorderRadius.circular(30)
                  ),
                  alignment: Alignment.center,
                  width: MediaQuery.of(context).size.width - 48,
                  child: Text("Register", style: TextStyle(color: Colors.white, fontSize: 16),),
                ),
              ),
              SizedBox(height: 18,),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  Text("Already have an account? ", style: TextStyle(fontSize: 15.5),),
                  GestureDetector(
                    onTap: (){
                      Navigator.pushReplacement(context, MaterialPageRoute(
                      builder: (context) => SignIn()
                      ));
                    },

                      child: Text("Sign in", style: TextStyle(fontSize: 15.5, decoration: TextDecoration.underline),))

                ],
              ),

              SizedBox(height: 80,),

            ],
            ),
          ),
        ),
      ),
    );;
  }
}

我尝试向子项添加 Expanded，它消除了错误，但输入数据时表单字段变得非常小。尝试在 SingleChildScrollView 中包装列，但它给了我以下内容

RenderFlex children have non-zero flex but incoming height constraints are unbounded

谁能指出我做错了什么？

谢谢!

Answer 1

您必须将 Form 小部件包装在 SingleChildScrollView 中。另请注意，添加 SingleChildScrollView 后没有固定高度，因此您无法使用 spacer 小部件。相反，您可以使用 SizedBox Widget 在上面留出一些空间。

final _formKey = GlobalKey<FormState>();
  String sName, fName, lName, email, phone, password;
  AuthService authService = new AuthService();
  bool _isLoading = false;

  signUp() async {
    if (_formKey.currentState.validate()) {
      setState(() {
        _isLoading = true;
      });
      authService.signUpWithEmailAndPass(email, password).then((value) {
        if (value != null) {
          setState(() {
            _isLoading = false;
          });
          Navigator.pushReplacement(
              context, MaterialPageRoute(builder: (context) => Home()));
        }
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: appBar(context),
        centerTitle: true,
        backgroundColor: Colors.transparent,
        elevation: 0.0,
        brightness: Brightness.light,
      ),
      body: _isLoading
          ? Container(
              child: Center(
                child: CircularProgressIndicator(),
              ),
            )
          : SingleChildScrollView(
              child: Form(
                key: _formKey,
                child: Container(
                  padding: EdgeInsets.symmetric(horizontal: 24),
                  child: Container(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: <Widget>[
                        // here you can't use spacer because their is no fix height, so you have to use SixedBox give some spacing
                        SizedBox(
                          height: 50,
                        ),
                        TextFormField(
                          validator: (val) {
                            return val.isEmpty ? "Enter School Name" : null;
                          },
                          decoration: InputDecoration(hintText: "School Name"),
                          onChanged: (val) {
                            sName = val;
                          },
                        ),
                        SizedBox(
                          height: 6,
                        ),
                        TextFormField(
                          validator: (val) {
                            return val.isEmpty ? "Enter First Name" : null;
                          },
                          decoration: InputDecoration(hintText: "First Name"),
                          onChanged: (val) {
                            fName = val;
                          },
                        ),
                        SizedBox(
                          height: 6,
                        ),
                        TextFormField(
                          validator: (val) {
                            return val.isEmpty ? "Enter Last Name" : null;
                          },
                          decoration: InputDecoration(hintText: "Last Name"),
                          onChanged: (val) {
                            lName = val;
                          },
                        ),
                        SizedBox(
                          height: 6,
                        ),
                        TextFormField(
                          validator: (val) {
                            return val.isEmpty ? "Enter Emailid" : null;
                          },
                          decoration: InputDecoration(hintText: "Email"),
                          onChanged: (val) {
                            email = val;
                          },
                        ),
                        SizedBox(
                          height: 6,
                        ),
                        TextFormField(
                          validator: (val) {
                            return val.isEmpty ? "Enter Phone Number" : null;
                          },
                          decoration: InputDecoration(hintText: "Phone"),
                          onChanged: (val) {
                            phone = val;
                          },
                        ),
                        SizedBox(
                          height: 6,
                        ),
                        TextFormField(
                          obscureText: true,
                          validator: (val) {
                            return val.isEmpty ? "Enter Password" : null;
                          },
                          decoration: InputDecoration(hintText: "Password"),
                          onChanged: (val) {
                            password = val;
                          },
                        ),
                        SizedBox(
                          height: 24,
                        ),
                        GestureDetector(
                          onTap: () {
                            signUp();
                          },
                          child: Container(
                            padding: EdgeInsets.symmetric(vertical: 18),
                            decoration: BoxDecoration(
                                color: Colors.blue,
                                borderRadius: BorderRadius.circular(30)),
                            alignment: Alignment.center,
                            width: MediaQuery.of(context).size.width - 48,
                            child: Text(
                              "Register",
                              style:
                                  TextStyle(color: Colors.white, fontSize: 16),
                            ),
                          ),
                        ),
                        SizedBox(
                          height: 18,
                        ),
                        Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          mainAxisSize: MainAxisSize.min,
                          children: <Widget>[
                            Text(
                              "Already have an account? ",
                              style: TextStyle(fontSize: 15.5),
                            ),
                            GestureDetector(
                                onTap: () {
                                  Navigator.pushReplacement(
                                      context,
                                      MaterialPageRoute(
                                          builder: (context) => SignIn()));
                                },
                                child: Text(
                                  "Sign in",
                                  style: TextStyle(
                                      fontSize: 15.5,
                                      decoration: TextDecoration.underline),
                                ))
                          ],
                        ),
                        SizedBox(
                          height: 80,
                        ),
                      ],
                    ),
                  ),
                ),
              ),
            ),
    );
  }
}