Transcript Intro to Graphical User Interfaces

Graphical User Interfaces
SE-1020
Dr. Mark L. Hornick
1
You’ve already done some Java
GUI programming
JOptionPane - a multi-purpose class whose
behavior varies based on which static method
you invoke
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showMessageDialog
showInputDialog
showConfirmDialog
showOptionDialog
SE-1020
Dr. Mark L. Hornick
2
JOptionPane. showMessageDialog()
provides a simple way to display a
message to the user:
JOptionPane.showMessageDialog(null, “I Love Java”);
SE-1020
Dr. Mark L. Hornick
3
JOptionPane. showInputDialog() provides
a way to prompt the user for some text
input:
String text =
JOptionPane.showInputDialog(null,
"Enter some text:", "Input dialog",
JOptionPane.QUESTION_MESSAGE);
SE-1020
Dr. Mark L. Hornick
4
JOptionPane.showConfirmDialog()
provides a way to present a variety of
standard button choices to the user:
response = JOptionPane.showConfirmDialog( null,
"Run Again?", "Confirmation",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE );
SE-1020
Dr. Mark L. Hornick
5
JOptionPane.showOptionDialog() provides
A way to customize the options presented
to the user beyond the standard choices:
Object[] options = { “Bye" };
JOptionPane.showOptionDialog(null,
"Game over; you're broke.",
"Please come again", JOptionPane.DEFAULT_OPTION,
JOptionPane.WARNING_MESSAGE,
null, options, options[0]);
SE-1020
Dr. Mark L. Hornick
6
There are a lot more GUI classes than
just JOptionPane
These are in two different packages

AWT (Abstract Window Toolkit) classes are
implemented by using the native GUI objects
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AWT classes for Windows are written differently than AWT
classes written for the MAC
A GUI application written on for a MAC will look different than
one written for a Windows-based PC
Swing classes are fully implemented in Java, and
behave the same on different operating systems.

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They provide greater compatibility across different operating
systems
(JOptionPane is part of javax.swing)
SE-1020
Dr. Mark L. Hornick
7
Swing classes support many more
functionalities not supported by AWT
counterparts
Rules for usage:

Do not mix the counterparts (e.g. AWT buttons and Swing
buttons) in the same program because of their differences in
implementation.

UNLESS there is no Swing counterpart to AWT (e.g. AWT
Graphics)

then it is OK to use AWT.
SE-1020
Dr. Mark L. Hornick
8
The JFrame class is the fundamental
“window” class
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It contains rudimentary functionalities to support features found in any frame
window.
A JFrame object serves as the “host” for containing other components,
JTextField
JLabel
JFrame
JButton
SE-1020
Dr. Mark L. Hornick
9