1 / 16

GUI Programming in Java

GUI Programming in Java. Tim McKenna Seneca@York. GUI Programming Concepts. conventional programming: sequence of operations is determined by the program what you want to happen, happens when you want it event-driven programming:

verdi
Télécharger la présentation

GUI Programming in Java

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. GUI Programming in Java Tim McKenna Seneca@York

  2. GUI Programming Concepts • conventional programming: • sequence of operations is determined by the program • what you want to happen, happens when you want it • event-driven programming: • sequence of operations is determined by the user’s interaction with the application’s interface • anything that can happen, happens at any time

  3. GUI Design Concepts • a wealth of information creates a poverty of attention- Herbert Simon • Principles of good GUI Design • IBM's Design concepts • Saul Greenberg's HCI pages • Tim's HCI notes

  4. GUI Programming Concepts in Java • Java GUI ("Swing") has components • Windows GUI has controls • Unix GUI has widgets • examples: labels,buttons, check boxes, radio buttons, text input boxes, pull down lists • Java Swing components: JLabel,JButton, JCheckBox, JRadioButton, JTextField, JTextArea, JComboBox

  5. Java GUI history: the AWT • AWT(JDK 1.0, 1.1): Abstract Window Toolkit • package: java.awt, java.awt.event • heavyweight components using native GUI system elements • used for applets until most browsers supported JRE 1.2

  6. Swing in Java • Swing(Java 2, JDK 1.2+) • lightweight components that do not rely on the native GUI or OS • “look and feel” of Swing components • are identical on different platforms • can be customized • Swing inherits from AWT • AWT still used for events, layouts

  7. Swing Components in Java • advanced GUI support. e.g. drag-and-drop • package names: javax.swing, javax.swing.event • components inherit from JComponent • components are added to a top-level container: JFrame, JDialog, or JApplet.

  8. running a Swing application • java -Dswing.aatext=true MySwingClass • the option sets the system property "swing.aatext" to "true" to enable anti-aliasing for every JComponent • javawruns a GUI without the console window • e.g. HelloWorldSwing.java

  9. Basic GUI Programming Stepsin Java • declare a container and components • add components to one or more containers using a layout manager • register event listener(s) with the components • create event listener method(s)

  10. Basic GUI Programming Concepts in Java • Example: JFrameDemoTM.java, JFrameDemoTM2.java, JFrameDemo.java • container : a screen window/applet window/panel that groups and arranges GUI components • GUI component: an object with visual representation • Swing containers: JFrame, JApplet, JPanel • AWT containers: Frame, Applet, Panel

  11. GUI Programming: The Java Approach • event-driven programming • a piece of code (i.e. event handler) is attached to a GUI component • an event handler is called when an event (e.g. a mouse click) is activated / fired • The Delegation Event Model in Java • processing of an event is delegated to an object (the listener) in the program

  12. Event-driven Programming in Java • event source: a GUI component that generates / fires an event • event: a user interaction (e.g. a click on the button) • event listener: an object that has implemented event handlers to react to an event

  13. Event Handling in Java • the delegation event model - event listeners must be registered with an event source in order to receive notification

  14. Event Handling in Java • registration of an event listener- write a class that implements an [event type]Listener interface - create an instance of that class (i.e. an event listener) - register the listener with a GUI component: add[event type]Listener ( <an event listener> )

  15. Event Handling in Java • a listener interface has a list of standard event handlers (i.e. methods) • API documentation - java.awt.event - event classes - listener interfaces - adapter classes

  16. Event Handling in Java • different ways of coding the event listeners • JFrameDemoTM.java uses named inner classes. • JFrameDemoTM2.java uses named inner classes and shows how to consolidate window closing from two different events. • JFrameDemo.java does not use inner classes.

More Related