mainAxisAlignment property

MainAxisAlignment mainAxisAlignment

How the children should be placed along the main axis.

If the direction is Axis.horizontal, and the mainAxisAlignment is either MainAxisAlignment.start or MainAxisAlignment.end, then the textDirection must not be null.

If the direction is Axis.vertical, and the mainAxisAlignment is either MainAxisAlignment.start or MainAxisAlignment.end, then the verticalDirection must not be null.

Implementation 

MainAxisAlignment get mainAxisAlignment => _mainAxisAlignment;
void mainAxisAlignment= (MainAxisAlignment value)

Implementation 

set mainAxisAlignment(MainAxisAlignment value) {
  assert(value != null);
  if (_mainAxisAlignment != value) {
    _mainAxisAlignment = value;
    markNeedsLayout();
  }
}