onLongPressDown property

The pointer has contacted the screen with a primary button, which might be the start of a long-press.

This triggers after the pointer down event.

If the user completes the long-press, and this gesture wins, onLongPressStart will be called after this callback. Otherwise, onLongPressCancel will be called after this callback.

See also:

• kPrimaryButton, the button this callback responds to.
• onSecondaryLongPressDown, a similar callback but for a secondary button.
• onTertiaryLongPressDown, a similar callback but for a tertiary button.
• LongPressGestureRecognizer.onLongPressDown, which exposes this callback at the gesture layer.