TextFromField

TextFormField是继承了TextFiled，

TextFormField一般是放在Form里面使用,可以使用GlobalKey进行控制：

 

 

首先在类里面声明GlobalKey，如：

final globalKeyValue=GlobalKey<FormState>();

其次在Form里面加入 key:GlobalKey,如：

key: globalKeyValue,

再次在TextFormFiled里面定义onSave(){}和validate(){}

onSaved: (value){username=value;},

validator: validateUsername,

String validateUsername(value){
  if(value.isEmpty){return 'Username is required';}else{return null;}
}

最后在使用下面这两句就直接调用了TextFormField内部定义的onSave(){}和validate(){}：

globalKeyValue.currentState.save();
globalKeyValue.currentState.validate();



附上一个示例：

import 'package:flutter/material.dart';

void main()=>runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final globalKeyValue=GlobalKey<FormState>();
  String username,password;
  bool boolSwich=false;
  String validateUsername(value){
    if(value.isEmpty){return 'Username is required';}else{return null;}
  }
  String validatePassword(value){
    if(value.isEmpty){return 'passWord is required';}else{return null;}
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('FormDemo'),),
      body: Form(
        key: globalKeyValue,
        child: Column(
          children: <Widget>[
            SizedBox(height: 5,),
            TextFormField(
              validator: validatePassword,
              autovalidate: boolSwich,
              onSaved: (value){username=value;},
              decoration: InputDecoration(
                contentPadding: EdgeInsets.all(5),
                fillColor: Colors.orangeAccent,
                filled: true,
                labelText: '输入标签',
                hintText: '输入用户名',
                helperText: '',
              ),
            ),
            SizedBox(height: 5,),
            TextFormField(
              obscureText: true,
              validator: validateUsername,
              autovalidate: boolSwich,
              onSaved: (value){password=value;},
              decoration: InputDecoration(
                contentPadding: EdgeInsets.all(5),
                fillColor: Colors.orangeAccent,
                filled: true,
                labelText: '输入标签',
                hintText: '输入密码',
                helperText: '',
              ),
            ),
            Container(
              padding: EdgeInsets.only(left: 18,right: 18),
              width: double.infinity,
              child: RaisedButton(
                  color: Colors.orangeAccent,
                  highlightColor: Colors.red,
                  child: Icon(Icons.save),
                  onPressed: (){
                    globalKeyValue.currentState.save();
                    globalKeyValue.currentState.validate();
                    debugPrint('username:$username');
                    debugPrint('password:$password');
                    boolSwich=true;
                  }
                  ),
            ),
          ],
        ),
      ),
    );
  }
}