Flutter -- iOS -- Stack

import 'package:flutter/material.dart';
import 'package:my/dart_01.dart';

void main(){
  runApp(new MaterialApp(
    title: 'Stack 布局示例Alignment',
    home: new MyApp(),
  ));
}


class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    var stack = new Stack(
      alignment: Alignment.topLeft,
      children: <Widget>[
        new CircleAvatar(
          backgroundImage: new AssetImage('images/750-1334-1.png'),
          radius: 100.0,
        ),
        new Container(
          decoration:  new BoxDecoration(
            color: Colors.black38,
          ),
          child: new Text(
            '我这里是文字显示',
            style: new TextStyle(
              fontSize: 22.0,
              fontWeight: FontWeight.bold,
              color: Colors.white,
            ),
          ),
        ),
      ],
    );

    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Stack 层叠布局示例'),
      ),
      body: new Center(
        child: stack,
      ),
    );
  }
}