Action 

Some UI elements such as the button element can react to a user’s interaction: clicking on the corresponding pushbutton can trigger a handling method to be called within the view controller. Such UI elements are equipped with one or several general events, which can be linked with a specific action at design time (switching to a subsequent view, for example). If such an action is created, an event handler method for this action is created automatically. In this way, you can equip a UI element event (which has been inserted several times into a view) with different actions as necessary. The event is then processed by the corresponding event handler depending on the action that is linked.

Actions can also be reused within a view. This means that an action can be linked to the events of several (or even different) UI elements.

UI element events are always handled within their own view controller; there is no cross-controller communication. UI element events themselves are predefined and cannot be changed.