container boxdecoration

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('DemoK'),
      ),
      body: Center(
        child: Container(
          width: 100,
          height: 100,
          decoration: BoxDecoration(
            border: Border.all(color: Colors.green, width: 10),
            shape: BoxShape.circle,
            gradient: RadialGradient(colors: [Colors.redAccent,Colors.blueAccent]),
            boxShadow: [
              BoxShadow(
                color: const Color(0xFFd0d0d0),
                blurRadius: 1.0,
                spreadRadius: 2.0,
                offset: Offset(10.0, 10.0),
              ),
              BoxShadow(
                color: Colors.redAccent,
                blurRadius: 2.0,
                spreadRadius: 6.0,
                offset: Offset(-20.0, -20.0),
              ),
            ]
          ),
          child: InkWell(
            onTap: () {
              setState(() {
                showDialog(
                    context: context,
                    builder: (data) {
                      return SimpleDialog(
                        backgroundColor: Colors.orange,
                        title: Text('我是对话框'),
                        children: <Widget>[
                          ListTile(
                            title: Text('hello'),
                            subtitle: Text('hi,lihua!'),
                          ),
                        ],
                      );
                    });
              });
            },
            child: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                  Icon(Icons.add),
                  Text(
                    'hello',
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}