The following items are key to designing an object-oriented user interface:
Objects and their relationships can be defined by answering the following questions:
To illustrate the importance of objects and their relationships, consider the example of the design of a software model of a car dealership. A salesperson needs a car object to represent each car model on his lot. He also needs a customer object to represent each customer that purchases a car. He needs a worksheet object to track sales, profits, inventory, customers, and so on. Finally, he needs container objects to group these objects.
The visual representations of objects must ensure consistency with one another and with the operating system. Visual representations of objects should address the functional aspects of visual representations, such as usability and purpose: Does the visual convey the purpose of the object being represented? Visual representations also should address the aesthetic aspects, such as shape, size, and color: Is the representation visually pleasing?
Users should interact with similar objects in similar ways and in ways that seem natural. Users also should have a choice of interaction mechanisms that suits their tasks, level of skill, and preferred style of interaction. In the car dealership example, a salesperson must be able to place information into a worksheet object in any of several ways. The salesperson can: