21.2 GridView.count 的使用

1.源代码

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
          backgroundColor: Colors.green,
          appBar: AppBar(title: Text("GridView.count"),),
          body: GridView.count(
            crossAxisCount: 3,
            childAspectRatio: 1,
            mainAxisSpacing: 5,
            crossAxisSpacing: 5,
            children: <Widget>[
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
            ],
          ),
        )
    );
  }
}

2.解释源代码

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
          backgroundColor: Colors.green,
          appBar: AppBar(title: Text("GridView.count"),),
          //效果跟上篇一样
          body: GridView.count(
            crossAxisCount: 3,
            childAspectRatio: 1,
            mainAxisSpacing: 5,
            crossAxisSpacing: 5,
            children: <Widget>[
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=1333189478,4259049031&fm=173&app=25&f=JPEG?w=640&h=640&s=6BA43A6238B07BA77D3C7CC60000E0E1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
              Image.network("https://ss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1147110391,1099568746&fm=173&app=25&f=JPEG?w=640&h=640&s=4BA43A625AFA7BAF7D302CC60000A0A1",width: 100,height: 180,),
            ],
          ),
        )
    );
  }
}

3.效果图