advertisement
javaboutique
Search Tips
Articles  |   Tutorials  |   Reviews  |   Tools  |   by Category  |   by Date  |   by Name  |   Submit  |   Source  |   Forums  |  
javaboutique
Browse DevX


Partners & Affiliates











advertisement



Title: Professional Java Programming
ISBN: 186100382x
US Price: $ 59.99
Canadian Price:
C$ 89.95
UK Price: £ 45.99
© Wrox Press Limited, US and UK.

Reviews : Java Books :
Professional Java Programming : Using Layout Managers

BoxLayout

Each of the five layout managers discussed so far is defined in the java.awt package and has been available since Java 1.0. However, BoxLayout is a more recent addition to Java and is included in the javax.swing package. BoxLayout is an attempt to provide some of the flexibility of GridBagLayout without the complexity involved in its use.

A BoxLayout allows you to create either a single row or a single column of components. In other words, the components you add to a BoxLayout are arranged vertically from top-to-bottom, or horizontally from left-to-right.

BoxLayout is different from the other layout managers in a number of ways, and uses some properties defined in Component that the other layout managers ignore. For example, BoxLayout respects a component's maximum size, and will never make the component larger than the dimensions specified by that property. In addition, a BoxLayout that arranges its components vertically (or a "vertical BoxLayout") uses each component's alignment along the X axis, which is available through the getAlignmentX() method in Component. Similarly, BoxLayout uses the components' alignments along the Y axis (and the corresponding getAlignmentY() method) when it arranges them horizontally.

BoxLayout is different from the other layout managers in one other important way: it uses a component's maximum size to determine the amount of space that the component should occupy. In many cases, a component's maximum size is the same as or is close to its preferred size. However, as we'll see later, some components have very large maximum size values, which can produce unexpected or undesirable results when used with a BoxLayout.

Alignment Values, Ascents and Descents

Component alignment values play a major role in determining how components are positioned within a BoxLayout-managed container, but before we can examine how alignment values are used, it's necessary to define some terms.

A component's alignment is represented by a float value that can range from 0.0 to 1.0, and you may find it helpful to think of this number as a percentage value, with 0.0 representing 0% and 1.0 representing 100%. By default, a component's X and Y alignment values are both set to 0.5. The component's ascent value is calculated by multiplying one of its dimensions by one of its alignment values. For example, if you're using a horizontal BoxLayout, you could calculate the preferred height ascent for a component by multiplying the component's preferred height by its Y alignment value, as in the following equation:

Dimension prefSize = comp.getPreferredSize();
int ascent = (int)(prefSize.height * comp.getAlignmentY());

Similarly, a component's descent value is calculated by subtracting the component's ascent value from the size that was used to calculate the ascent, as shown below:

int descent = prefSize.height - ascent;

In other words, the sum of the ascent and descent values is equal to the dimension that was used to calculate them, and they represent the portions of the component that lie on either side of an imaginary line. For example, suppose that the above code was executed for a component with a preferred height of 400 pixels, and that the component's Y alignment value is 0.25. The ascent value would be 100 (400 * 0.25 = 100), while the descent value would be 300 (400 - 100 = 300).

How to Add Java Applets to Your Site

New on the Java Boutique:

New Review:

Time Management Made Easy with the Quartz Enterprise Job Scheduler
Why not just use the Java timer API? This open source scheduling API boasts simplicity, ease-of-integration, a well-rounded feature set, and it's free!

New Applet:

Reverse Complement
Reverse Complement is a simple applet that converts DNA or RNA sequences into three useful formats.

Elsewhere on internet.com:

WebDeveloper Java
Lots of Java information on webdeveloper.com

WDVL Java
Thorough Java resource at the Web Developer's Virtual Library.

ScriptSearch Java
Hundreds of free Java code files to download.

jGuru: Your View of the Java Universe
Customizable portal with online training, FAQs, regular news updates, and tutorials.

 Microsoft Visual Studio 2010 Showcase
 Avaya Developer Showcase
 MSDN Spotlight
 PHP for Windows Showcase
XML error: undefined entity at line 39
advertisement
Receive Articles via our XML/RSS feed
Receive Articles via our XML/RSS feed

JavaBytes
Internet Cyclone
This powerful, easy-to-use, internet optimizer is for Windows 95, 98, ME, NT, 2000 and XP. It's designed to automatically optimize your Windows settings, boosting your Internet connection up to 200%.

Windows 7: From Beta to Final Code in One Year
Google Shows Off Chrome OS, Releases Source
Microsoft Shows Off Silverlight 4, IE9 Plans
Metasploit Expands Vulnerability Test Framework
HyperCard Reborn?
Fedora 12 Takes Aim at Linux Networking
Top Supercomputer Nearly Doubles in Speed
Fedora 12 Linux Tackles Virtualization
Apple Gives iPhone Developers App Status Tracker
Novell Sets OpenSUSE 11.2 Free

Creating Custom Export Filters for StarOffice with XSLT
WPF Wonders: Using DataTemplates
Crystal Reports Family Offers Options for Developers
Avaya Aura Session Manager video
Avaya Aura Overview video
Exploring HTML 5's Audio/Video Multimedia Support
Overriding Virtual Functions? Use C++0x Attributes to Avoid Bugs.
Understanding the Cloud Computing Security Vulnerabilities
Cisco and IBM Target a Greener World
Upgrade to Visual Studio 2010 with the Ultimate Offer

Advertising Info  |   Member Services  |   Contact Us  |   Help  |   Feedback  |   Site Map  |   Network Map  |   About

internet.commediabistro.comJusttechjobs.comGraphics.com

Search:

WebMediaBrands Corporate Info

Legal Notices, Licensing, Permissions, Privacy Policy.
Advertise | Newsletters | Shopping | E-mail Offers | Freelance Jobs