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Java Programming, Lecture Notes # 1023
- Preface
- Introduction
- Sample Program
- Interesting Code Fragments
- Summary
- Where To From Here?
- Complete Program Listing
Preface
Viewing tip
You may find it useful to open another copy of this lesson in a separate browser window. That will make it easier for you to scroll back and forth among the different figures and listings, without losing your place, while you are reading about them.
Recommended supplementary reading
I recommended that you study the three previous tutorials in this series — Swing from A to Z: The Border Property (Part 1, EtchedBorder), Swing from A to Z: The Border Property (Part 2, BevelBorder and EmptyBorder), and Swing from A to Z: The Border Property (Part 3, CompoundBorder) — before embarking on this lesson.
I also recommended that in addition to studying this set of lessons, you also study my earlier lessons on Swing, which are available at Gamelan. A consolidated index to those earlier lessons is available here.
Introduction
This lesson illustrates the use of LineBorder, MatteBorder, and TitledBorder.
Two different variations of MatteBorder are illustrated. One uses a tiled icon to create the matte and the other uses a solid color.
Sample Program
The name of the sample program that I will discuss to illustrate borders is Swing13.
A screen shot of the GUI that is produced when the program is started is shown in Figure 1 below.
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Twelve JLabel objects
The program creates and displays twelve different JLabel objects, applying a different border style to each of them.
In this lesson, I will be concentrating on the components appearing in the bottom four rows of the screen shot.
Interesting Code Fragments
Compound Empty + LineBorder,10,10
Listing 1 shows the code fragment that caused the label in the seventh row of the screen shot to be added to the contentPane of the JFrame container. This is the label with the narrow blue border showing.
| getContentPane().add(makeLabel( “Compound, Empty + LineBorder”, new CompoundBorder(new LineBorder( Color.blue,5),new EmptyBorder( 5,5,5,5)))); Listing 1 |
Familiar syntax
By now, you are familiar with (and possibly bored with) this syntax, so I won’t discuss it in detail.
Briefly, this fragment uses a CompoundBorder object to combine a LineBorder object and an EmptyBorder object to form the visible border.
As in the previous lesson, the EmptyBorder is used to provide a blank margin between the text and the LineBorder.
What does Sun have to say?
Here is what Sun has to say about LineBorder.
| A class which implements a line border of arbitrary thickness and of a single color. |
The constructors
Two simple overloaded constructors are available. Each let you specify the color of the line. One defaults to a line thickness of one pixel. The other lets you specify the thickness of the line in pixels.
In this case, I specified a blue line with a thickness of five pixels.
The inset values were each ten pixels, resulting from the sum of the blank area and the width of the line.
Compound Empty + MatteBorder Image,24,24
Listing 2 shows the code fragment that caused the label in the eighth row of the screen shot to be added to the contentPane of the JFrame container. This is the ugly label with the blue balls in its border.
| getContentPane().add(makeLabel( “Compound, Empty + MatteBorder Image”, new CompoundBorder(new MatteBorder( 19,19,19,19,new ImageIcon( “blue-ball.gif”)),new EmptyBorder( 5,5,5,5)))); Listing 2 |
This rather ugly component uses a CompoundBorder object to combine a MatteBorder object and an EmptyBorder object.
MatteBorder class
Here is what Sun has to say about MatteBorder.
| A class which provides a matte-like border of either a solid color or a tiled icon. |
Although the MatteBorder class is easy to use from a technical viewpoint, it can be a challenge from a cosmetic viewpoint when icons are used to produce the border. As you can see, mine didn’t turn out to be very pleasing.
Dimensions are very important
In order to design a component with a pleasing appearance, the designer would need to be very careful about the size of the icon, the insets of the outside MatteBorder, and the insets of the inside EmptyBorder. Otherwise, the result isn’t balanced, as is the case in my example.
Compound Empty + MatteBorder Color,24,24
Listing 3 shows the code fragment that caused the label in the ninth row of the screen shot to be added to the contentPane of the JFrame container. This is the label with the wide blue border.
| getContentPane().add(makeLabel( “Compound, Empty + MatteBorder Color”, new CompoundBorder(new MatteBorder( 19,19,19,19,Color.blue), new EmptyBorder(5,5,5,5)))); Listing 3 |
This is a very straightforward fragment. It uses EmptyBorder to place a five-pixel blank band around the original JLabel component.
Then it uses MatteBorder to place a 19-pixel blue matte around the blank band, producing an overall inset value of 24 pixels.
Compound Empty + TitledBorder,10,26
Here is what Sun has to say about TitledBorder.
| A class which implements an arbitrary border with the addition of a String title in a specified position and justification.
If the border, font, or color property values are not specified in the constructor or by invoking the appropriate set methods, the property values will be defined by the current look and feel, using the following property names in the Defaults Table:
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This can be a very complex component. The TitledBorder class has six overloaded constructors that provide a wide variety of options in the construction of the object.
Listing 4 shows the code fragment that caused the label in the bottom row of the screen shot to be added to the contentPane of the JFrame container.
| getContentPane().add(makeLabel( “Compound, Empty + TitledBorder”, new CompoundBorder(new TitledBorder( “Title”),new EmptyBorder(5,5,5,5)))); Listing 4 |
As you can see, I elected to use the simplest form of constructor, which required only that I provide a string for the title.
Summary
I have also mentioned that if the standard borders won’t fulfill your needs, you can define your own borders by defining a class that implements the Border interface.
Where To From Here?
Complete Program Listing
| /*File Swing13 Rev 3/28/00 Copyright 2000, R.G.Baldwin Illustrates the border property. This Tested using JDK 1.2.2 under WinNT 4.0 WkStn import java.awt.*; class Swing13 extends JFrame{ //—————————————// public static void main(String args[]) { //The purpose of this method is to create JLabel label = new JLabel(); label.setText(content + “,” return label; }//end makeLabel() Swing13(){//constructor getContentPane().setLayout( getContentPane().add(makeLabel( getContentPane().add(makeLabel( getContentPane().add(makeLabel( getContentPane().add(makeLabel( setTitle(“Copyright 2000, R.G.Baldwin”); //……………………………….// }//end constructor }//end class Swing13 Listing 5 |
Copyright 2000, Richard G. Baldwin. Reproduction in whole or in part in any form or medium without express written permission from Richard Baldwin is prohibited.
About the author
Richard Baldwin is a college professor and private consultant whose primary focus is a combination of Java and XML. In addition to the many platform-independent benefits of Java applications, he believes that a combination of Java and XML will become the primary driving force in the delivery of structured information on the Web.
Richard has participated in numerous consulting projects involving Java, XML, or a combination of the two. He frequently provides onsite Java and/or XML training at the high-tech companies located in and around Austin, Texas. He is the author of Baldwin’s Java Programming Tutorials, which has gained a worldwide following among experienced and aspiring Java programmers. He has also published articles on Java Programming in Java Pro magazine.
Richard holds an MSEE degree from Southern Methodist University and has many years of experience in the application of computer technology to real-world problems.
