Java_21_JFrame_Show_Colors_1

Some general notations:

Graphics applications typically employ many classes.

Many of these classes are part of the Abstract Windows Tools (AWT)

To see the wealth of classes available in Java use the website: http://docs.oracle.com/javase/7/docs/api

Comments about the JFrame example:

The JFrame application ShowColors is a driver type class.

In the class ShowColors, presented in the previous 2 slides, we saw the following methods/constructor:

1 - main(), which is the regular driver method for any application on your computer. In this case its main job is to create a ShowColors object with the reference “application”. This will call the constructor with no parameters. A secondary job is to provide the feature “X” on the top right corner of the frame created, which if clicked will close the frame.

2 - The constructor ShowColors() contains 3 calls to JFrame methods: super(), passes to the JFrame constructor a text which will appear on the frame title bar, setSize() gives the width and the height of the frame, and show().

3 - The Graphics method paint() is overwritten in class ShowColors. Class Graphics is above class JFrame in the inheritance tree of Java Development Kit.

4 - The Graphics methods drawString() and fillRect() use x,y coordinates.