|Widgets (Components) Example Code
Fall 2002, David Matuszek
Components (also known as widgets) are the various user controls and displays provided by the Java AWT; they are the basic building blocks of a Graphical User Interface. The following illustration shows the most common AWT components:
This is a "live" applet, not just a picture of an applet
(try it!). Each of the components in the above applet, when manipulated, places
a message in the status line of the applet (in the above illustration, the status
line contains the text
Applet started.) When you run the applet
appletviewer, the status line is shown at the bottom of the
applet; when you run the applet in a browser, the status line is usually shown
at the bottom of the browser window (although some browsers may not show the
status line at all).
The code for this applet illustrates:
I recommend that you download the source code for the above applet and keep it handy. When you want to use a particular kind of component, you can use this code as a model for how to create the component and handle the events that it generates.
There are two versions of the source code for this applet:
Widgets.java uses anonymous inner classes; complete BlueJ package is in WidgetsAnonymous.zip.
Widgets2.java uses member classes; complete BlueJ package is in WidgetsMembers.zip.
In general, member classes are easier to understand, while anonymous inner classes are more convenient.
.jar file is just like a
.zip file, and you
can use WinZip or equivalent to unpack it.