Flutter align two items on extremes – one on the left and one on the right

Use a single Row instead, with mainAxisAlignment: MainAxisAlignment.spaceBetween.

new Row(
  mainAxisAlignment: MainAxisAlignment.spaceBetween,
  children: [
    new Text("left"),
    new Text("right")
  ]
);

Or you can use Expanded

new Row(
  children: [
    new Text("left"),
    new Expanded(
      child: settingsRow,
    ),
  ],
);