Vertical viewport was given unbounded height

Question

This is my code:

  @override
  Widget build(BuildContext context) {
    return new Material(
      color: Colors.deepPurpleAccent,
      child: new Column(
           


        

Answer 1

put grid view inside Flexible or Expanded widget

return new Material(
    color: Colors.deepPurpleAccent,
    child: new Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children:[
         Flexible(
          child:  GridView.count(crossAxisCount: _column,children: new List.generate(_row*_column, (index) {
          return new Center(
             child: new CellWidget(),
          );
        }),))]
    )
);