如何在Flutter中获取TextField的值

Question

我在Flutter中创建了注册界面。我想在FlatButton的onPressed中获取电子邮件和密码。

有人知道如何在Flutter中实现吗？

  Widget SignupPage() {
    return new Scaffold(body: Container(
      height: MediaQuery.of(context).size.height,
      decoration: BoxDecoration(
        color: Colors.white,
        image: DecorationImage(
          colorFilter: new ColorFilter.mode(
              Colors.black.withOpacity(0.05), BlendMode.dstATop),
          image: AssetImage('assets/images/mountains.jpg'),
          fit: BoxFit.cover,
        ),
      ),
      child: new Column(
        children: <Widget>[
          Container(
            padding: EdgeInsets.all(100.0),
            child: Center(
              child: Icon(
                Icons.headset_mic,
                color: Colors.redAccent,
                size: 50.0,
              ),
            ),
          ),
          new Row(
            children: <Widget>[
              new Expanded(
                child: new Padding(
                  padding: const EdgeInsets.only(left: 40.0),
                  child: new Text(
                    "EMAIL",
                    style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Colors.redAccent,
                      fontSize: 15.0,
                    ),
                  ),
                ),
              ),
            ],
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
            alignment: Alignment.center,
            decoration: BoxDecoration(
              border: Border(
                bottom: BorderSide(
                    color: Colors.redAccent,
                    width: 0.5,
                    style: BorderStyle.solid),
              ),
            ),
            padding: const EdgeInsets.only(left: 0.0, right: 10.0),
            child: new Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                new Expanded(
                  child: TextField(
                    obscureText: true,
                    textAlign: TextAlign.left,
                    decoration: InputDecoration(
                      border: InputBorder.none,
                      hintText: 'PLEASE ENTER YOUR EMAIL',
                      hintStyle: TextStyle(color: Colors.grey),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Divider(
            height: 24.0,
          ),
          new Row(
            children: <Widget>[
              new Expanded(
                child: new Padding(
                  padding: const EdgeInsets.only(left: 40.0),
                  child: new Text(
                    "PASSWORD",
                    style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Colors.redAccent,
                      fontSize: 15.0,
                    ),
                  ),
                ),
              ),
            ],
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
            alignment: Alignment.center,
            decoration: BoxDecoration(
              border: Border(
                bottom: BorderSide(
                    color: Colors.redAccent,
                    width: 0.5,
                    style: BorderStyle.solid),
              ),
            ),
            padding: const EdgeInsets.only(left: 0.0, right: 10.0),
            child: new Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                new Expanded(
                  child: TextField(
                    obscureText: true,
                    textAlign: TextAlign.left,
                    decoration: InputDecoration(
                      border: InputBorder.none,
                      hintText: '*********',
                      hintStyle: TextStyle(color: Colors.grey),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Divider(
            height: 24.0,
          ),
          new Row(
            children: <Widget>[
              new Expanded(
                child: new Padding(
                  padding: const EdgeInsets.only(left: 40.0),
                  child: new Text(
                    "CONFIRM PASSWORD",
                    style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Colors.redAccent,
                      fontSize: 15.0,
                    ),
                  ),
                ),
              ),
            ],
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
            alignment: Alignment.center,
            decoration: BoxDecoration(
              border: Border(
                bottom: BorderSide(
                    color: Colors.redAccent,
                    width: 0.5,
                    style: BorderStyle.solid),
              ),
            ),
            padding: const EdgeInsets.only(left: 0.0, right: 10.0),
            child: new Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                new Expanded(
                  child: TextField(
                    obscureText: true,
                    textAlign: TextAlign.left,
                    decoration: InputDecoration(
                      border: InputBorder.none,
                      hintText: '*********',
                      hintStyle: TextStyle(color: Colors.grey),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Divider(
            height: 24.0,
          ),
          new Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.only(right: 20.0),
                child: new FlatButton(
                  child: new Text(
                    "Already have an account?",
                    style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Colors.redAccent,
                      fontSize: 15.0,
                    ),
                    textAlign: TextAlign.end,
                  ),
                  onPressed: () => {},
                ),
              ),
            ],
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 30.0, right: 30.0, top: 50.0),
            alignment: Alignment.center,
            child: new Row(
              children: <Widget>[
                new Expanded(
                  child: new FlatButton(
                    shape: new RoundedRectangleBorder(
                      borderRadius: new BorderRadius.circular(30.0),
                    ),
                    color: Colors.redAccent,
                    onPressed: () => authHandler.handleSignInEmail(emailController.text, passwordController.text)
                        .then((FirebaseUser user) {
                      Navigator.push(context, new MaterialPageRoute(builder: (context) => HomePage()));
                    }).catchError((e) => print(e)),
                    child: new Container(
                      padding: const EdgeInsets.symmetric(
                        vertical: 20.0,
                        horizontal: 20.0,
                      ),
                      child: new Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: <Widget>[
                          new Expanded(
                            child: Text(
                              "SIGN UP",
                              textAlign: TextAlign.center,
                              style: TextStyle(
                                  color: Colors.white,
                                  fontWeight: FontWeight.bold),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    ));
  }

- N Sharma

Answer 1

在您的State类中将TextEditingController创建为全局变量，并将其设置为您的TextField小部件。

final TextEditingController emailController = TextEditingController();

@override
  void dispose() {
    // Clean up the controller when the widget is disposed.
    emailController.dispose();
    super.dispose();
  }

TextField(
  controller: emailController,
  obscureText: true,
  textAlign: TextAlign.left,
  decoration: InputDecoration(
    border: InputBorder.none,
    hintText: 'PLEASE ENTER YOUR EMAIL',
    hintStyle: TextStyle(color: Colors.grey),
  ),
)

现在，您可以使用以下方法获取该值：

emailController.text

您可以在此处获取更多信息：https://flutter.dev/docs/cookbook/forms/retrieve-input

- diegoveloper

---

我有三个文本框，我需要三个文本编辑器吗？ - Aderbal Nunes

是的，或者您可以使用每个文本字段的onChanged方法，并将值保存到每个文本字段的本地变量中。 - diegoveloper

@diegoveloper，我在一个表单中有10个文本框和下拉按钮字段。有没有一种方法可以获取所有元素的值？还是我必须通过TextEditingController.text函数逐个获取每个元素的值？请建议。谢谢。 - Kamlesh

必须使用Stateful小部件吗？ - junhan

是的，否则每次重建在您的无状态组件上面的任何小部件时，您的文本编辑控制器都将被销毁。 - diegoveloper

Answer 2

我认为另一种更容易的选项是在TextField类中添加'onChanged'属性，该属性将包含字符串

String enteredText .... TextField( onChanged: (newText) { enteredText = newText; },

- Adi

---

"onChanged" 会在每个字符改变时触发，对吗？ - Hasan Abdullah

@HasanAbdullah 是的，你说得对。 - ᴅ ᴇ ʙ ᴊ ᴇᴇ ᴛ

Answer 3

文本字段在用户更改字段中的文本时调用 onChanged 回调。如果用户表示他们已完成在字段中输入（例如，通过按软键盘上的按钮），则文本字段将调用 onSubmitted 回调。

使用这些回调，我们可以设置 实例变量 并在提交按钮的 onPress 上使用这些变量。

- Dinesh Balasubramanian

Answer 4

在build方法之前创建TextEditingController。

TextEditingController yourControllerName = new TextEditingController();

然后在TextField中传递控制器，如下所示：

TextField(
           controller: yourNameController,
           // your extra stuff
          )

假设您想在文本中访问它，则可以像这样访问：

Text(
     yourControllerName.text.toString(), // this will convert your controller to String
     )

谢谢，希望它能够正常运行！！！

- Aditya Aggarwal