read / write
Called when a pointer has contacted the screen at a particular location with a secondary button, which might be the start of a long-press.
This triggers after the pointer down event.
- kSecondaryButton, the button this callback responds to.
- onLongPressDown, a similar callback but for a primary button.
- onTertiaryLongPressDown, a similar callback but for a tertiary button.
- LongPressDownDetails, which is passed as an argument to this callback.
- GestureDetector.onSecondaryLongPressDown, which exposes this callback in a widget.