flutter 输入框

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("按钮列表"),
        ),
        body: MyHomeBody(),
      ),
    );
  }
}

class MyHomeBody extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return HomeContent();
  }
}

class HomeContent extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Container(
      padding: EdgeInsets.all(20),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          TextFieldDemo(),
        ],
      ),
    );
  }
}

class TextFieldDemo extends StatefulWidget {
  TextFieldDemoState createState() => TextFieldDemoState();
}

class TextFieldDemoState extends State<TextFieldDemo> {
  final textEditingController = TextEditingController();

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    // 设置默认值
    textEditingController.text = "Hello World";

    // 监听 文本框
    textEditingController.addListener(() {
      print("textEditingController: ${textEditingController.text}");
    });
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return TextField(
      controller: textEditingController,
      decoration: InputDecoration(
        icon: Icon(Icons.people),
        labelText: "用户名",
        hintText: "请输入用户名",
        border: InputBorder.none,
        filled: true,
        fillColor: Colors.lightGreen,
      ),
      onChanged: (value) {
        print("onChanged: $value");
      },
      onSubmitted: (value) {
        print("onSubmitted: $value");
      },
    );
  }
}