Question

我是Flutter的新手，正在尝试向codelabs - flutter学习。 TextField小部件不会显示。我在这里停留了一个小时。

我最终复制了代码方法，但仍然使我的应用程序为空。

这是我的代码：

class ChatScreen extends StatefulWidget{
//  @override
//  State createState() => new ChatScreenState();

  @override
  State<StatefulWidget> createState() {
    return new ChatScreenState();
  }
}

//STATE OF CHAT SCREEN
class ChatScreenState extends State<ChatScreen>{

  //NEW COMPONENT EDIT TEXT INPUT LAYOUT
  final TextEditingController _textController = new TextEditingController();

  //WIDGET METHOD
  Widget _buildTextComposer() {
    return new Container(
      margin: const EdgeInsets.symmetric(horizontal: 8.0),
      child: new TextField(
        controller: _textController,
        onSubmitted: _handleSubmitted,
        decoration: new InputDecoration.collapsed(hintText: "Send a message"),
      ),
    );

  }

  //METHOD FOR CLEARING
  void _handleSubmitted(String text){
    _textController.clear();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: _buildTextComposer(),

    );
  }

}

我已经包括了脚手架中的尸体：_buildTextComposer()。

Answer 1

来自codelabs教程

codelabs-flutter #3，我没有注意到它们对runApp()

进行了更改

发件人：

import 'package:flutter/material.dart';

void main() {
  runApp(
    new MaterialApp(
      title: "Friendlychat",
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text("Friendlychat"),
        ),
      ),
    ),
  );
}

收件人：

void main() {
  runApp(new FriendlychatApp()); //THERE IS NO COMMENT INDICATING THIS IS MODIFIED
}

他们在某些页面中指出了这一点。右边的评论

// Modify the ChatScreen class definition to extend StatefulWidget.

class ChatScreen extends StatefulWidget {                     //modified
  @override                                                        //new
  State createState() => new ChatScreenState();                    //new
}

Flutter文本字段小部件不会显示

1 个答案: