Flutter stretch columns to full screen height

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Each container contains a column allowing you to add multiple widgets.

return Scaffold(
      backgroundColor: Color(0xFF222222),
      body: SafeArea(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            Expanded(
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  Expanded(
                    child: Container(
                      color: Colors.red,
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.start,
                        children: <Widget>[
                          Text('Left', textAlign: TextAlign.center),
                          Text('Left', textAlign: TextAlign.center),
                          Text('Left', textAlign: TextAlign.center),
                        ],
                      ),
                    ),
                  ),
                  Expanded(
                    child: Container(
                      color: Colors.green,
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.end,
                        children: <Widget>[
                          Text('Right', textAlign: TextAlign.center),
                          Text('Right', textAlign: TextAlign.center),
                          Text('Right', textAlign: TextAlign.center),
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
            Expanded(
              child: Container(
                color: Colors.blue,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    Text('Bottom', textAlign: TextAlign.center),
                    Text('Bottom', textAlign: TextAlign.center),
                    Text('Bottom', textAlign: TextAlign.center),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );