flutter - 如何在 flutter 中将输入值从扩展子小部件返回到父小部件

Question

我在理解如何将输入信息从扩展子小部件传递回其父小部件时遇到问题。我试图在父小部件中创建一个 setter，但我无法通过“ParentWidget.of(context).setterName”调用它。

将用户输入信息从子窗口小部件传递回父窗口小部件的最佳方式是什么？

谢谢你的帮助

class SignInMobilePortrait extends StatefulWidget {
  @override
  _SignInMobilePortraitState createState() => _SignInMobilePortraitState();
}

class _SignInMobilePortraitState extends State<SignInMobilePortrait> {

  //text field state
  String _email = '';

  set email(String value) => setState(() => _email = value);

  ...

  LoginCredentials(),

  ...

}

class LoginCredentials extends StatelessWidget {

  LoginCredentials({
    Key key,
  }) : super(key: key);

  Widget build(BuildContext context) {    
    return Container(

     ...

                onChanged: (value) {
                 //CHANGE EMAIL VALUE HERE;
                },
     ...
}

Answer 1

执行此操作的正确方法是将 TextEditingController 从 SignInMobilePortrait 向下传递到 LoginCredentials:

class _SignInMobilePortraitState extends State<SignInMobilePortrait> {

  final _emailController = TextEditingController();

  LoginCredentials(_emailController),

  ...
  // Access _emailController.text somewhere

}


class LoginCredentials extends StatelessWidget {
  final TextEditingController controller;
  LoginCredentials({
    Key key,
    @required this.controller,
  }) : super(key: key);

  Widget build(BuildContext context) {    
    return TextField(
     ...
     controller: controller,
}