Set dynamically crossAxisCount param about flutter_staggered_grid_view HOT 5 CLOSED

`import 'package:flutter/material.dart';
import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';

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

class MyApp extends StatefulWidget {
  static const String _title = 'Flutter Code Sample';

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

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: MyApp._title,
      home: MyStatelessWidget(),
    );
  }
}

/// This is the stateless widget that the main application instantiates.
class MyStatelessWidget extends StatefulWidget {
  MyStatelessWidget({Key key}) : super(key: key);

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

class _MyStatelessWidgetState extends State<MyStatelessWidget> {
  bool isMosaic=false;
//  bool isMosaic=true;  (UNCOMMENT THIS - if this starts out as TRUE it will work fine)

  @override
  Widget build(BuildContext context) {
    return Scaffold(

      body:
      CustomScrollView(
          physics: AlwaysScrollableScrollPhysics(),

          slivers: <Widget>[
       SliverStaggeredGrid.countBuilder(
      crossAxisCount: isMosaic ? 2 : 1,
      itemCount: 10,
      staggeredTileBuilder: (index) => StaggeredTile.fit(1),
    mainAxisSpacing: isMosaic ? 2.0 : 0.0,
    crossAxisSpacing: 2.0,
    itemBuilder: (context, index) {
    return SizedBox(
    height: (!isMosaic ? 350 : index.isEven ? 380 : 320),
    width: 200,
    child: Container (
      color: Colors.grey,
    child: Text(index.toString(), textAlign: TextAlign.center, textScaleFactor: 4.0,)
      ));
    }
    )]),

      floatingActionButton: FloatingActionButton(
        onPressed: changeIt,

        child: Icon(Icons.shuffle),

      ),
    );
  }

  void changeIt () {
    setState(() {
      isMosaic = !isMosaic;
    });
  }
}