Discussion

The cancel button item controls the Cancel button displayed in the navigation bar when the step view controller is current. This property lets you control the appearance and target of the Cancel button at runtime.

When the value of the property is nil, the Cancel button is not displayed; otherwise, the title, target, and action associated with the Cancel button item are used (other properties of UIBarButtonItem are ignored).

The cancel button item is updated during view loading and when the value of the step property is changed, but is safe to set in the taskViewController:stepViewControllerWillAppear: delegate callback.

Subclasses can safely modify this property any time after calling viewWillAppear: on super.