Question: New to flutter, can some one tells me whats wrong with below code[![enter image description here](https://i.stack.imgur.com/5b5lp.png)](https://i.stack.imgur.com/5b5lp.png)

```
  class GamePage extends StatelessWidget {
  int _row;
  int _column;

  GamePage(this._row,this._column);

  @override
  Widget build(BuildContext context) {
    return new Material(
      color: Colors.deepPurpleAccent,
      child:new Expanded(
          child:new GridView.count(crossAxisCount: _column,children: new List.generate(_row*_column, (index) {
        return new Center(
            child: new CellWidget()
        );
      }),) )

    );
  }
}

```

Attaching error screenshot.

Answer: 
Crash
=====

This crashes because Expanded is not a descendant of a Flex widget:

```
Container(
  child: Expanded(
    child: MyWidget(),
  ),
)

```

Acceptable
==========

Here Expanded *is* a descendant of Flex:

```
Flex(
  direction: Axis.horizontal,
  children: [
    Expanded(
      child: MyWidget(),
    ),
  ],
)

```

Row is also a Flex widget:

```
Row(
  children: [
    Expanded(
      child: MyWidget(),
    ),
  ],
)

```

And so is Column:

```
Column(
  children: [
    Expanded(
      child: MyWidget(),
    ),
  ],
)

```

Another option is to just get rid of the Expanded widget:

```
Container(
  child: MyWidget(),
)

```
sometimes it can also happen if you have an expended widget inside the SingleChildScrollView widget, then it shows the blank screen. If you have any expended widget inside SingleChildScrollView remove it and it will solve the problem.

**Before**

```
  body: SingleChildScrollView(
     child: Column(
     children: [
      Container(),
       Expanded(
       child: Container(),
        ),
       ],
      ),
      ),

```

**After**

```
  body: SingleChildScrollView(
     child: Column(
     children: [
      Container(),
      Container(),
       ],
      ),
      ),

```