onTapDown property Null safety
final
A pointer that might cause a tap with a primary button has contacted the screen at a particular location.
This is called after a short timeout, even if the winning gesture has not yet been selected. If the tap gesture wins, onTapUp will be called, otherwise onTapCancel will be called.
See also:
- kPrimaryButton, the button this callback responds to.
Implementation
final GestureTapDownCallback? onTapDown;