Padding控件即填充控件，能给子控件插入给定的填充。

import 'package:flutter/material.dart';
class LayoutDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('填充'),),body: new Padding(
        padding: const EdgeInsets.all(50.0),child: new Image.network('http://up.qqjia.com/z/25/tu32710_4.jpg'),);
  }
}
void main() {
  runApp(
    new MaterialApp(
      title: 'Flutter教程',home: new LayoutDemo(),);
}