Flutter学习笔记八——GridView Widget

认识GridView组件并简单使用

先看一个简单的例子，使用Text组件作为GrideView的item：

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "GridView",
      home: Scaffold(
        appBar: AppBar(
          title: Text("GridView Widget"),
        ),
        body: GridView.count(
          crossAxisCount: 3,
          padding: EdgeInsets.all(10.0),
          crossAxisSpacing: 10.0,
          children: <Widget>[
            const Text("this is 1 item"),
            const Text("this is 2 item"),
            const Text("this is 3 item"),
            const Text("this is 4 item"),
            const Text("this is 5 item"),
          ],
        ),
      ),
    );
  }
}

效果如图：

GridView.jpg

• padding：表示内边距
• crossAxisCount：表示每行显示的网格个数
• crossAxisSpacing：表示每个网格之间的间距。

这样并不太直观，下面使用图片组件作为GrideView的item：

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "GridView",
      home: Scaffold(
          appBar: AppBar(
            title: Text("GridView Widget"),
          ),
          body: GridView(
            padding: EdgeInsets.all(1.0),
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                crossAxisCount: 3,
                mainAxisSpacing: 2.0,
                crossAxisSpacing: 2.0,
                childAspectRatio: 0.75),
            children: <Widget>[
              Image.network(
                  "http://img5.mtime.cn/mt/2019/02/21/095918.47882172_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mt/2019/01/25/100901.82440600_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mg/2019/02/19/095714.33859824_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mt/2019/01/25/105549.53627008_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mt/2019/03/01/142658.85498591_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mt/2019/01/09/171109.88229500_270X405X4.jpg",
                  fit: BoxFit.cover),
              Image.network(
                  "http://img5.mtime.cn/mg/2019/02/26/103754.10526344_270X405X4.jpg",
                  fit: BoxFit.cover)
            ],
          )),
    );
  }
}

效果如图：

imgGrid.jpg

• childAspectRatio: 表示宽高比，即宽是高的多少倍，0.75=3/4
• mainAxisSpacing:可以理解为行间距
• crossAxisSpacing:可以理解为列间距