onDoubleTapDown property Null safety

GestureTapDownCallback? onDoubleTapDown
read / write

A pointer has contacted the screen with a primary button at the same location twice in quick succession, which might be the start of a double tap.

This triggers immediately after the down event of the second tap.

If this recognizer doesn't win the arena, onDoubleTapCancel is called next. Otherwise, onDoubleTap is called next.

See also:

Implementation

GestureTapDownCallback? onDoubleTapDown;