Why when i set height are double.infinity ,it shows a bug in the display? : my code look like this 
```
  get _pdfViewer{
    if(pathPDF != null) return Container(
      child: PdfViewer(
        filePath: pathPDF,
      ),
      color: Colors.red,
    );
    else return Container(height: 30,color: Colors.blueAccent,);
  }
Column(
        children: <Widget>[
          Flex(
            direction: Axis.horizontal,
            children: <Widget>[
              Expanded(
                flex: 7,
                child:  Container(
                  height: 500,
                  color: Colors.blueAccent,
                  child: _pdfViewer,
                ),
              ),
              Expanded(
                flex: 1,
                child:Container(
                  height:500,
                  color: Colors.green,
                )
              ),
            ],
          )
        ],
      );
```
in the code has twice heights, when i make the height to  **double.infinity** its worry(error) look like this:
[image][1]

i want to max of the screen in the application.what should i do?


  [1]: https://i.stack.imgur.com/1lu62.png