TextFormField验证器，错误在TextFormField上不可见

Question

我正在尝试创建一个带有列的表单。

例如，表单=>列=> TextFields，

TextFields将有验证器。此外，TextFields将有装饰。

但是，当我单击RaisedButton时，我在TextField上找不到错误。尽管成功地执行了TextFormField中的返回。(我用调试器检查)

到目前为止，我提到的链接如下：https://www.youtube.com/watch?v=xiEYNzU4bDg

https://iirokrankka.com/2017/10/17/validating-forms-in-flutter/

https://medium.com/@nitishk72/form-validation-in-flutter-d762fbc9212c

下面是我的代码，请求帮助我解决这个问题。

import 'package:flutter/material.dart';

class Profile extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return new ProfileState();
  } //createState closes here....
} //Profile closes here.....

class ProfileState extends State<Profile> {
  @override
  Widget build(BuildContext context) {
    final _formKey = GlobalKey<FormState>();

    return new Scaffold(
        appBar: new AppBar(title: new Text("Profile")),
        body: Form(
          key: _formKey,
          child: new Column(
            children: <Widget>[
              //Full Name TextGormFeild goes below....
              new TextFormField(
                  validator: (String value) {
                    if (value.isEmpty) {
                      return "Full name cannot be empty.";//Control comes here when I check using the Debugger.
                    } //if(value.isEmpty) closes here....
                  },
                  keyboardType: TextInputType.text,
                  textInputAction: TextInputAction.next,
                  maxLines: 1,
                  decoration: InputDecoration(
                      border: new OutlineInputBorder(
                          borderSide: new BorderSide(color: Colors.grey)),
                      hintText: "Enter name")),

              new RaisedButton(
                child: new Text("Test"),
                onPressed: () {
                  setState(() {
                    if (_formKey.currentState.validate()) {
                      print("Validations are correct.");
                    }
                  });
                },
              )
            ],
          ),
        )

        //,
        // helperText: "Enter full name"
        );
  } //build closes here.....

} //ProfileState closes here....

早些时候我使用helperText，但我已经删除了它。

Answer 1

尝试从您的setState中删除onPressed

setState(() {

});

只放

if (_formKey.currentState.validate()) {
  print("Validations are correct.");
}

如下所示：

onPressed: () {
    if (_formKey.currentState.validate()) {
      print("Validations are correct.");
    }
},