CS 112
Spring 2005
Ileana Streinu

• Writing code in an object oriented fashion:
  • everything is inside some class, which defines what an object of that type looks like.
  • objects are created with new.
  • methods (functions) are applied to objects using the dot notation.
  • the current class is referred to (within itself) with this.
• Basic Graphical User Interface (GUI) objects:
• button
• text box
• canvas
• label
• Basic Graphics objects:
• circle, rectangle
• text, fomt
• color, background color
• Writing code in an event-driven programming environment:
• the program must specify which events are to be expected (repainting of the applet, button clicks, etc.). Next time we will learn also about mouse clicks.
• the program must specify code to implement certain event-handling methods: actionPerformed. Next time we also learn about methods to handle mouse events (mousePressed, actionPerformed, etc.), by writing a separate event handles (e.g. MouseHandler extending MouseAdapter).
• the program must implement certain methods which are always executed when certain events occur (init, paint, etc.)

Blackboard pictures

• Creating a new object (Button). Terminology: class variables.
• Declaration and allocation of a variable.
• Each class has a constructor, except the applet (which has init).
• Structure of an applet with button. Structure of an applet with graphics.