Introduction

Content

Apply

Reflect

Extend

Review Question 2

In simple applets, so far we have used the applet's ‘paint()' method to display text or graphics in the applet. However, in this unit we said that this was a bad idea. Rather than displaying graphics directly on an applet, it was suggested that you should create a new object and place this in an applet. For example, we could create a new object which is a subclass of Canvas (a blank area of screen) and use its paint method to do the drawing. This object could then be inserted in the applet using ‘add'. A skeleton of a program that works this way may look something like this:

Class MyApplet extends Applet

{

public MyApplet()

{

// This is the constructor.

// Create a new object of class Drawing and put it in

// the applet

add(new Drawing());

}

}

class Drawing

{

public void paint (Graphics g)

{

// All the drawing methods go here….

}

}

So in this example, all the drawing methods are in the class Drawing and the applet itself has no graphics methods.

This approach leads to a longer program, and it is more complex (at least superficially). So what are the advantages of this programming strategy?

Discussion

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