Swing GUI Components

Now it’s time to learn about the set of Swing GUI components (sometimes referred to as “widgets”).

The Model-View-Controller Architecture

Swing has adopted the (highly successful) Model-View-Controller (MVC) architecture.

MVC is a commonly-used pattern for Graphical User Interfaces:

  • Each component has three characteristics:
    • its contents, or state.
    • its visual appearance
    • its behavior (reaction to events)
  • These characteristics are represented by:
    • The model, which stores the contents/state, and has no user interface
    • The view, which displays the contents;  there can be more than one view for a model.
    • The controller, which handles user input.

Model-View-Controller Interactions

Example

For example, take a very simple component, a button:

  • The model stores the content:
    • Whether the button is currently pushed in or out, active or inactive, etc.
    • The text to be displayed (if any)
  • The view displays the representation of that content:
    • The visual indication of the button’s state (in or out, active, etc.)
    • The text (if any), clipped if doesn’t fit within the confines of the visual representation.
  • The controller handles the user input events:
    • Mouse clicks
    • Keystrokes

and translates them into any appropriate changes in the model and/or view.