The target/action pattern is part of the mechanism by which user interface controls respond to user actions, enabling users to communicate their intentions to an application. The target/action pattern specifies a one-to-one relationship between two objects; the control (more specifically, the control’s cell) and its target. When a user clicks a user interface control, the control sends an action message to the target object as depicted in Figure 6.23.
Figure 6-23. Target/action
The target/action relationship is typically defined using Interface Builder, in which you select a target object for a control, along with the specific action message that will be sent to the target. Target/action relationships can also be set (or modified) while an application is running.
The following steps take you through the process of building a simple example application that uses the target/action pattern. In this example, clicking a button in the main window causes the date and time to be updated in a text field.
Since the first example provided detailed instructions on creating projects using Project Builder, this example generally does not repeat those instructions. If you forget how to do a step, refer back to the Nib Files project in Section 6.2 to refresh your recollection.
Start Project Builder, if it is not already running. ...