Offstage 控制是否显示组件

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final appTitle = "Offstage控制是否显示组件";
    return MaterialApp(
      title: appTitle,
      home: MyHomePage(title: appTitle),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;
  MyHomePage({Key key, this.title}) : super(key: key);
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
//  状态控制是否显示文本组件
  bool offstage = true;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Offstage(
//          控制是否显示
          offstage: offstage,
          child: Text(
            '我出来啦！',
            style: TextStyle(
              fontSize: 36.0,
            ),
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
//          设置是否显示文本组件
          setState(() {
            offstage = !offstage;
          });
        },
        tooltip: "显示隐藏",
        child: Icon(Icons.flip),
      ),
    );
  }
}