Welcome!

Java IoT Authors: Elizabeth White, Kevin Benedict, Sematext Blog, Liz McMillan, Jnan Dash

Related Topics: Java IoT

Java IoT: Article

FrameResizer

Resizing windows

This article presents a Java/Swing component implementation of a feature that is ubiquitous in nearly all desktop applications, particularly Windows applications - an area in the lower right portion of a window (Frame) that can be used to resize the window.

Of course, a window can be re-sized with most desktop managers by dragging the lower-right edge - the additional component simply serves as a visual indicator of the resize capability, and also increases the margin of error for the mouse drag.

Typically this component is placed in a status or message area at the bottom of a window. I demonstrate my solution in the context of a very simple (and barely func-tional) Web browser. I also introduce a technique in which a Frame/JFrame/JInternalFrame can exhibit "continuous layout" behavior as it is resized.

Details
The component is called Frame-Resizer. It subclasses JComponent and has two main jobs that it performs. First, it draws itself and, second, it handles mouse events so that it can both change the mouse cursor (on mouse enter/leave) and resize the window (on mouse press/drag/release). FrameResizer can be used to resize a Frame, JFrame, or JInternalFrame, each of which has a common ancestor of java.awt.Container in the component class hierarchy. So constructors for FrameResizer take a Container argument as follows:

public FrameResizer(Container parent);
public FrameResizer(Container parent, boolean useContinuousLayout);

Rendering
Figure 1 shows the FrameResizer in its typical context, at the lower right edge of a window, as part of a status/message area.

FrameResizer draws itself in the paintComponent() method as shown in Listing 1. There are seven "ribs" that make up the component.

A rib is one of the raised "bumps" in the component visual; it's actually just two 2x2 pixel rectangles drawn in different colors offset slightly from each other. You can see this in the exploded view of the FrameResizer in Figure 2.

Resizing
Much of the interesting FrameResizer code is in the MouseInputListener inner class that the component adds to itself. In the mouseEntered() and mouseExited() methods, the cursor is changed to Cursor.NW_RESIZE_CURSOR and the default Cursor, respectively. In the mousePressed() method (see Listing 2), the mouse location is converted to actual screen coordinates, and the relative location from edge of the window (the Point mouseAdjust) is calculated.

In the mouseDragged() method (see Listing 3), the current mouse position is again converted to absolute screen position, and the new bounds of the parent Container (Frame/InternalFrame) are recalculated based on the original mouse location.

The mouseReleased() method calls mouseDragged() for a final calculation, and then "validates" the parent container. Since FrameResizer supports either an external Frame or a JInternalFrame, the validate() method does the appropriate validation and invokes the repaint() method (see Listing 4). This needs to be done at the end of the AWT EventDispatchThread (thus the use of SwingUtilities.invokeLater()). This method is declared static so it can be re-used for the "continuous layout" functionality (see below).

Continuous Layout
This concept is familiar to Swing developers who use JSplitPane - it's the ability to have internal components validate and repaint as the container is resized (in real time). Unfortunately, when a top-level Java desktop window is resized, this doesn't happen, as the validate/repaint messages are not sent to the underlying Container until resizing (via mouse dragging) is complete. Figure 3 is a capture of our browser window during the mouse drag. You can see how the contents of the window are not "stretched' to fit the bounds of the Frame - this is done when the mouse is released.

Ideally you want the contents of the window to stretch to the frame bounds during resizing. This capability is evident in most non-Java top-level desktop windows.

The trick to doing this in Java is to use a Timer to periodically check the current bounds of the window (Frame), and if it has changed since the last interval, send the validate/repaint messages to the Frame. You can see how this is done in Listing 5. I coded it as a static method in FrameResizer so this functionality can be used independently of the component.

The code uses a static HashMap (continuousLayoutWindows) so it can be used for multiple windows in a multi-frame application. It lazily initializes this HashMap. In the map it stores the current Container bounds keyed by the Container. If the current bounds are different than what is in the map, the current bounds are saved and the validate and repaint messages are sent to the Container (our static validate() method from before). That's all there is to it. I use 100 milliseconds (hard-coded) as my timer interval - feel free to experiment with this number (or parameterize it).

You can specify whether or not "continuous layout" is used by the FrameResizer in its constructor (the default is true). Note that one drawback to "continuous layout" in this context is the flicker that occurs during the repaint. This is unfortunately unavoidable. Also note that the continuous layout behavior is not required if you are using the FrameResizer in the context of a JInternalFrame.

Summary
In this article I presented a custom Swing component that can be used to help provide a customary look and feel to a Frame or JInternalFrame. I've also introduced the concept of "continuous layout" to top-level Java desktop windows and shown how this can be implemented. The source code for this article can be downloaded from http://jdj.sys-con.com.

More Stories By Phil Herold

Phil Herold is VP and CTO of PocketScience LLC in Research Triangle Park, NC. He has over 24 years of experience in software engineering, and has been working with Java client technologies since 1996.

Comments (4) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Phil Herold 09/28/05 10:43:13 AM EDT

The link for the code to this article has been fixed. Here's the direct link:

http://res.sys-con.com/story/aug05/117759/FrameResizer.zip

This contains a jar file with both source and class files. If your run the jar with javaw, it will run the "Lame Browser" window that is shown in the article.

Phil Herold 09/26/05 09:59:47 AM EDT

Michael,

Someone in a private e-mail pointed out that Toolkit.setDynamicLayout() will accomplish the same thing as the timer/validate-paint technique used in my article. I haven't tried it, but you might look at that as well.

Michael Bushe 08/12/05 08:05:03 PM EDT

Brilliant!!! I've been writing fancy Swing apps for a long time and never even considered that there was a way around the gray-screen-as-you-resize problem. Very slick, very thorough. An icon for this was meticulously created by Jonathan Simon here:
http://today.java.net/pub/a/today/2005/06/07/pixelpushing.html

Bill Winspur 08/12/05 06:10:43 PM EDT

Very interesting article - unfortunately I cant find a link to the source code in the article, or on http://jdj.sys-con.com . Can somebody provide it?

@ThingsExpo Stories
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
Developing software for the Internet of Things (IoT) comes with its own set of challenges. Security, privacy, and unified standards are a few key issues. In addition, each IoT product is comprised of (at least) three separate application components: the software embedded in the device, the back-end service, and the mobile application for the end user’s controls. Each component is developed by a different team, using different technologies and practices, and deployed to a different stack/target –...
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management solutions, helping companies worldwide activate their data to drive more value and business insight and to transform moder...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
Digital innovation is the next big wave of business transformation based on digital technologies of which IoT and Big Data are key components, For example: Business boundary innovation is a challenge to excavate third-party business value using IoT and BigData, like Nest Business structure innovation may propose re-building business structure from scratch, as Uber does in the taxicab industry The social model innovation is also a big challenge to the new social architecture with the design fr...
If you had a chance to enter on the ground level of the largest e-commerce market in the world – would you? China is the world’s most populated country with the second largest economy and the world’s fastest growing market. It is estimated that by 2018 the Chinese market will be reaching over $30 billion in gaming revenue alone. Admittedly for a foreign company, doing business in China can be challenging. Often changing laws, administrative regulations and the often inscrutable Chinese Interne...
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, provided tips on how to be successful in large scale machine learning...
In his session at @ThingsExpo, Kausik Sridharabalan, founder and CTO of Pulzze Systems, Inc., will focus on key challenges in building an Internet of Things solution infrastructure. He will shed light on efficient ways of defining interactions within IoT solutions, leading to cost and time reduction. He will also introduce ways to handle data and how one can develop IoT solutions that are lean, flexible and configurable, thus making IoT infrastructure agile and scalable.
Data is an unusual currency; it is not restricted by the same transactional limitations as money or people. In fact, the more that you leverage your data across multiple business use cases, the more valuable it becomes to the organization. And the same can be said about the organization’s analytics. In his session at 19th Cloud Expo, Bill Schmarzo, CTO for the Big Data Practice at EMC, will introduce a methodology for capturing, enriching and sharing data (and analytics) across the organizati...
Internet of @ThingsExpo has announced today that Chris Matthieu has been named tech chair of Internet of @ThingsExpo 2016 Silicon Valley. The 6thInternet of @ThingsExpo will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Bsquare has been named “Silver Sponsor” of SYS-CON's @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. For more than two decades, Bsquare has helped its customers extract business value from a broad array of physical assets by making them intelligent, connecting them, and using the data they generate to optimize business processes.
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...
Video experiences should be unique and exciting! But that doesn’t mean you need to patch all the pieces yourself. Users demand rich and engaging experiences and new ways to connect with you. But creating robust video applications at scale can be complicated, time-consuming and expensive. In his session at @ThingsExpo, Zohar Babin, Vice President of Platform, Ecosystem and Community at Kaltura, will discuss how VPaaS enables you to move fast, creating scalable video experiences that reach your...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Businesses are struggling to manage the information flow and interactions between all of these new devices and things jumping on their network, and the apps and IT systems they control. The data businesses gather is only helpful if they can do something with it. In his session at @ThingsExpo, Chris Witeck, Principal Technology Strategist at Citrix, will discuss how different the impact of IoT will be for large businesses, expanding how IoT will allow large organizations to make their legacy ap...