onStart property
A pointer has contacted the screen with a primary button and has begun to move.
The position of the pointer is provided in the callback's details
argument, which is a DragStartDetails object.
Depending on the value of dragStartBehavior, this function will be called on the initial touch down, if set to DragStartBehavior.down or when the drag gesture is first detected, if set to DragStartBehavior.start.
See also:
- kPrimaryButton, the button this callback responds to.
- DragStartDetails, which is passed as an argument to this callback.
Implementation
GestureDragStartCallback? onStart;