Object–action interface
Overview
Object Action Interface, also abbreviated as OAI, is an extension to the Graphical User Interface, especially related to Direct Manipulation User Interface.It emphasises upon how Direct Manipulation User Interface (DMUI) can help to create better Human Computer Interfaces, and how it can increase the usability of the product.
There are basically two similar models regarding OAI:
- Object Action Interface:
This model focusses on the priority of the Object over the actions. It emphasizes on the object being selected first, and then any action performed on it. OAI adheres to this model.
- Action Object Interface:
This model suggests that the user of the interface specify the action before stating what object the action be performed upon. An example of this model can be Command Line Interface (e.g. copy <Source_File> <Destination_File>, here the action "copy" is specified prior to the object "file").
In the present context, the interface design is overwhelmed by GUIs. And hence more concern is given to the visual representation of the user's task objects and actions.It helps to reduces the adverse effect in case the users switch their mind mode from task domain to tool domain.
OAI Model
The OAI model graphically represents the users' workplace using metaphors and let the users perform action(s) on the object. The sequence of work is to first select the object graphically (using mouse or other pointing device), and then performing an action on the selected object. The result/effect of the action is then shown graphically to the user. This way, the user is relived from memory limitation, and syntactical complexity of the actions. Moreover, it emulates WYSIWYG. This feature of OAI lets the user control their sequence of action and visualize the effects at the runtime. If an action results into an undesired effect, the user simply reverses his sequence of actions.
In the Action-Object model, the computer is seen as a tool to perform different action. Whereas in the Object-Action model, the user gains a great sense of control from the feeling of a direct involvement. The computer in this case is seen as a medium through which different tools are represented, which is isomorphic to interacting with objects in the real world.
Designing an OAI model starts with examining and understanding the tasks to be performed by the system. The domain of tasks include the universe of objects within which the user works to accomplish a certain goal as well as the domain of all possible actions performed by the user. Once these tasks objects and actions are agreed upon, the designer starts by creating an isomorphic representation of the corresponding interface objects and actions.