You can use the container, It will help you to set the alignment.
Widget _buildListWidget({Map reminder}) {
return Container(
color: Colors.amber,
alignment: Alignment.centerLeft,
padding: EdgeInsets.all(20),
height: 80,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Container(
alignment: Alignment.centerLeft,
child: Text(
reminder['title'],
textAlign: TextAlign.left,
style: TextStyle(
fontSize: 16,
color: Colors.black,
backgroundColor: Colors.blue,
fontWeight: FontWeight.normal,
),
),
),
Container(
alignment: Alignment.centerRight,
child: Text(
reminder['Date'],
textAlign: TextAlign.right,
style: TextStyle(
fontSize: 12,
color: Colors.grey,
backgroundColor: Colors.blue,
fontWeight: FontWeight.normal,
),
),
),
],
),
);
}