gridview - 脚手架主体中的多个Gridview构建器

Question

在我看来，必须添加多个垂直Gridview来从数据库中加载数据。

问题是，当我将Gridviews添加到列或Wrap中时，由于高度不固定而出现错误。
如何在正文中添加多个Gridview？

Answer 1

使用Container进行包装，还检查height和rinkleWrap:true，以下示例演示GridView.builder和GridView.count

完整的代码

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  List<String> data = ["abc", "def", "kkk","aaa", "abc", "def", "kkk","aaa", "abc", "def", "kkk","aaa", "abc", "def", "kkk","aaa", "abc", "def", "kkk","aaa"];

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: SingleChildScrollView(
        child: Column(
          children: <Widget>[
            Container(
              height: 300,
              color: Colors.white30,
              child: GridView.count(
                  shrinkWrap: true,
                  crossAxisCount: 4,
                  childAspectRatio: 1.0,
                  padding: const EdgeInsets.all(4.0),
                  mainAxisSpacing: 4.0,
                  crossAxisSpacing: 4.0,
                  children: <String>[
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                    'https://www.fnordware.com/superpng/pngtest16rgba.png',
                  ].map((String url) {
                    return GridTile(
                        child: Image.network(url, fit: BoxFit.cover));
                  }).toList()),
            ),
            Container(
              height: 300,
              color: Colors.white30,
              child: GridView.builder(
                shrinkWrap: true,
                itemCount: data.length,
                gridDelegate: new SliverGridDelegateWithFixedCrossAxisCount(
                    crossAxisCount: 2),
                itemBuilder: (BuildContext context, int index) {
                  return new Card(
                    child: new GridTile(
                      //footer: new Text(data[index]),
                      child: new Text(data[index]), //just for testing, will fill with image later
                    ),
                  );
                },
              ),
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}