Vertical drag

    
      
onVerticalDragStart - A pointer has contacted the screen and
might begin to move vertically.
      
onVerticalDragUpdate - A pointer in contact with the screen
has moved further in the vertical direction.
      
onVerticalDragEnd - A pointer that was previously in contact with the
screen and moving vertically is no longer in contact with the screen and was
moving at a specific velocity when it stopped contacting the screen.

Horizontal drag

    
      
onHorizontalDragStart - A pointer has contacted the screen and might begin
to move horizontally.
      
onHorizontalDragUpdate - A pointer in contact with the screen
has moved further in the horizontal direction.
      
onHorizontalDragEnd - A pointer that was previously in contact with the
screen and moving horizontally is no longer in contact with the
screen and was moving at a specific velocity when it stopped
contacting the screen.

The following example shows a GestureDetector
that rotates the Flutter logo on a double tap: