Flutter:Stack组件结合Align/Positioned组件使用，实现对每个子组件分别进行定位

import 'package:flutter/material.dart';

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("首页"),
        centerTitle: true,
      ),
        body: HomeBody()
    );
  }
}

class  HomeBody extends StatefulWidget {
  @override
   _HomeBodyState createState() =>  _HomeBodyState();
}

class  _HomeBodyState extends State <HomeBody> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        width: 400,
        height: 400,
        color: Colors.red,
        child: Stack(
          // fit: StackFit.expand,
          children: [
            Align(
              alignment: Alignment.topCenter,
              child: Icon(Icons.home,size: 40,color: Colors.white,)
            ),
            Align(
              alignment: Alignment(0,0),
              child: Icon(Icons.home,size: 60,color: Colors.blue,)
            ),
            Align(
              alignment: Alignment(1,1),
              child: Icon(Icons.home,size: 50,color: Colors.green,)
            ),
          ],
        ),
      ),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:douban_demo/network/http_request.dart';
class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("首页"),
        centerTitle: true,
      ),
        body: HomeBody()
    );
  }
}

class  HomeBody extends StatefulWidget {
  @override
   _HomeBodyState createState() =>  _HomeBodyState();
}

class  _HomeBodyState extends State <HomeBody> {

  @override
  void initState() {
    // TODO: implement initState
    print("进入首页init");
    super.initState();
    // HttpRequest.request("https://api.douban.com/v2/user/:name");
  }
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        width: 400,
        height: 400,
        color: Colors.red,
        child: Stack(
          // fit: StackFit.expand,
          children: [
            Positioned(
              top: 0,
              left:10,
              child: Icon(Icons.home,size: 40,color: Colors.white,)
            ),
            Positioned(
              bottom: 0,
              left: 100,
              child: Icon(Icons.home,size: 60,color: Colors.blue,)
            ),
            Positioned(
              top: 200,
              left: 200,
              child: Icon(Icons.home,size: 50,color: Colors.green,)
            ),
          ],
        ),
      ),
    );
  }
}