A demonstration of the types of GridViews used.

gridview_demo.dart

//
//   https://fluttercentral.com/Articles/Post/45
//
//   Author: Seven Srikanth 
//
import 'package:flutter/material.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      home: DefaultTabController(
          length: 5,
          child: Scaffold(
              appBar: AppBar(
                  title: Text('Grid Demo'),
                  bottom: TabBar(
                    tabs: [
                      Tab(
                        text: 'GridView',
                      ),
                      Tab(
                        text: 'GridView.Count',
                      ),
                      Tab(
                        text: 'GridView.builder',
                      ),
                      Tab(
                        text: 'GridView.custom',
                      ),
                      Tab(
                        text: 'GridView.extent',
                      ),
                    ],
                    isScrollable: true,
                  )),
              body: TabBarView(children: [
                GridView(
                  scrollDirection: Axis.vertical,
                  controller: ScrollController(),
                  gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
                      maxCrossAxisExtent: 200.0),
                  children: List.generate(100, (index) {
                    return Container(
                      padding: EdgeInsets.all(20.0),
                      child: Center(
                        child: GridTile(
                          footer: Text(
                            'Item $index',
                            textAlign: TextAlign.center,
                          ),
                          header: Text(
                            'SubItem $index',
                            textAlign: TextAlign.center,
                          ),
                          child: Icon(Icons.access_alarm,
                              size: 40.0, color: Colors.white30),
                        ),
                      ),
                      color: Colors.blue[400],
                      margin: EdgeInsets.all(1.0),
                    );
                  }),
                ),
                GridView.count(
                    crossAxisCount: 2,
                    children: List.generate(100, (index) {
                      return Container(
                        padding: EdgeInsets.all(20.0),
                        child: Center(
                          child: GridTile(
                            footer: Text(
                              'Item $index',
                              textAlign: TextAlign.center,
                            ),
                            header: Text(
                              'SubItem $index',
                              textAlign: TextAlign.center,
                            ),
                            child: Icon(Icons.access_alarm,
                                size: 40.0, color: Colors.white30),
                          ),
                        ),
                        color: Colors.blue[400],
                        margin: EdgeInsets.all(1.0),
                      );
                    })),
                GridView.builder(
                  itemCount: 50,
                  gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                      crossAxisCount: 3),
                  itemBuilder: (BuildContext context, int index) {
                    //if (index < 50)
                    return Container(
                      padding: EdgeInsets.all(20.0),
                      child: Center(
                        child: GridTile(
                          footer: Text(
                            'Item $index',
                            textAlign: TextAlign.center,
                          ),
                          header: Text(
                            'SubItem $index',
                            textAlign: TextAlign.center,
                          ),
                          child: Icon(Icons.access_alarm,
                              size: 40.0, color: Colors.white30),
                        ),
                      ),
                      color: Colors.blue[400],
                      margin: EdgeInsets.all(1.0),
                    );
                  },
                ),
                GridView.custom(
                    gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                        crossAxisCount: 3),
                    childrenDelegate:
                    SliverChildListDelegate(List.generate(100, (index) {
                      return Container(
                        padding: EdgeInsets.all(20.0),
                        child: Center(
                          child: GridTile(
                            footer: Text(
                              'Item $index',
                              textAlign: TextAlign.center,
                            ),
                            header: Text(
                              'SubItem $index',
                              textAlign: TextAlign.center,
                            ),
                            child: Icon(Icons.access_alarm,
                                size: 40.0, color: Colors.white30),
                          ),
                        ),
                        color: Colors.blue[400],
                        margin: EdgeInsets.all(1.0),
                      );
                    }))),
                GridView.extent(
                  maxCrossAxisExtent: 200.0,
                  children: List.generate(100, (index) {
                    return Container(
                      padding: EdgeInsets.all(20.0),
                      child: Center(
                        child: GridTile(
                          footer: Text(
                            'Item $index',
                            textAlign: TextAlign.center,
                          ),
                          header: Text(
                            'SubItem $index',
                            textAlign: TextAlign.center,
                          ),
                          child: Icon(Icons.access_alarm,
                              size: 40.0, color: Colors.white30),
                        ),
                      ),
                      color: Colors.blue[400],
                      margin: EdgeInsets.all(1.0),
                    );
                  }),
                )
              ]))),
    );
  }
}

void main() {
  runApp(MyApp());
}