Click here to close now.




















Welcome!

Java IoT Authors: Pat Romanski, Adrian Bridgwater, Elizabeth White, Nicholas Lee, Dana Gardner

Related Topics: Java IoT

Java IoT: Article

GUI Design Patterns

Choosing data from long lists

Long lists of data present a problem for GUI development. This occurs when choosing records from large database tables or recipients from a long list of e-mail addresses, or any time a subset of data must be chosen from a long list or table.

Two issues arise when choosing from long lists of data. First, what is the best GUI for long lists so that the users understand how to navigate and manipulate their data? Second, if the list holds more than a few hundred items, performance become an issue.

In this article, simple examples show how to optimize usability for this common GUI design pattern. In a later article, more complex examples will show how to optimize performance for long lists.

GUI Design Patterns
In the late 1990s, a GUI design pattern emerged for choosing multiple objects from long lists. The book GUI Design Essentials by Susan Weinschenk, et al, called this the Selection Summary pattern. In "A Dual Listbox Selection Manager" by Steve Aube, it's also known as the Dual Listbox Selection interface. In "The Java Look and Feel Guidelines, Advanced Topics" by Sun Microsystems, it's called the Add-and-Remove idiom. Figure 1 shows an example of this GUI design pattern.

The Add-and-Remove design pattern has many variations. One common enhancement is to provide "Move Up" and "Move Down" buttons to reorder the chosen list. Sometimes the chosen list is displayed as a table (as in Figure 2) to show additional information.

This GUI design pattern has several advantages. By presenting the original and chosen lists in a symmetric layout, learning is simplified: once users learn one part of the GUI, the corresponding part works consistently. Also, because objects are moved from one location to another, directional icons and disabling can be used to guide the user.

The most important advantage of a standard GUI design like this is that because it is widely known, users will most likely have seen it before and therefore understand it quickly. A standard GUI design pattern is the simplest way to achieve usability.

Lay Out the Components
Listing 1 shows how this GUI design pattern can be implemented using the Swing components JList, JScrollPane, ImageIcon, and GridBagLayout. The GridBagLayout enables the alignment of unequal-sized components and provides good behavior on resizing. For a basic implementation, we need a grid with three columns and five rows. Lists, labels, and buttons are placed using GridBagConstraints so that when the component is resized, the lists grow or shrink while other components retain their original size (see Figure 3).

To support the Add-and-Remove pattern, the list contents must be mutable; i.e., the lists must dynamically change in response to the button presses. The DefaultListModel provides mutable storage that performs satisfactorily for lists of moderate size.

In Listing 1, the ActionListener interface connects the buttons to the lists. The actionPerformed method uses the button text to determine which of the four buttons was pressed.

The code in Listing 1 produces the GUI shown in Figure 4.

The DefaultListModel is not the default ListModel. By default, JLists use an internal ListModel that is immutable: you can't change its contents. This internal ListModel is efficient when applications only need to view a list because it doesn't carry the overhead of changing list contents.

To change list contents, as in the Add-and-Remove pattern, requires a mutable ListModel. Swing provides one in javax.swing.DefaultListModel, and it gives good performance for most applications. For long lists DefaultListModel is not particularly fast, and a later article will show how to improve on its performance.

Follow the Guidelines
"The Java Look and Feel Guidelines" specify precise spacings in multiples of six pixels between components. To follow these guidelines, EmptyBorders are added around the buttons and labels.

_originalLabel.setBorder(
  BorderFactory.createEmptyBorder( 0, 0, 6, 0 ));
_chosenLabel.setBorder(
  BorderFactory.createEmptyBorder( 0, 0, 6, 0 ));
_add.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 5, 11 ),
  _add.getBorder()));
_addAll.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 11, 11 ),
  _addAll.getBorder()));
_remove.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 5, 11 ),
  _remove.getBorder()));
_removeAll.setBorder(
  BorderFactory.createCompoundBorder(
  BorderFactory.createEmptyBorder( 0, 11, 0, 11 ),
  _removeAll.getBorder()));

The Guidelines also recommend mnemonics to support keyboard equivalents of mouse actions, as shown in the code below.

_add.setMnemonic( 'A' );
_addAll.setMnemonic( 'l' );
_remove.setMnemonic( 'R' );
_removeAll.setMnemonic( 'v' );

Note the difference between Figures 4 and 5. By following the guidelines, the GUI appearance is improved.

This example uses the guidelines for the Java ("Metal") Look and Feel. If you target a different platform the guidelines will be different. For example, Windows Guidelines specify different spacings between the components.

Whatever the target platform, the reason for following guidelines is to make life easier for the user. When your application looks and works the way the users expect, they have less to learn.

Help the Users Learn
"The Java Look and Feel Guidelines, Advanced Topics" by Sun recommends the use of icons in the buttons. If icons are stored with the ListChooser class, they can be assigned with the following code.

_add.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/add.gif" )));
_add.setHorizontalTextPosition( SwingConstants.LEFT );
_addAll.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/addAll.gif" )));
_addAll.setHorizontalTextPosition( SwingConstants.LEFT );
_remove.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/remove.gif" )));
_remove.setHorizontalTextPosition( SwingConstants.RIGHT );
_removeAll.setIcon( new ImageIcon(
  ListSelector.class.getResource( "images/removeAll.gif")));
_removeAll.setHorizontalTextPosition( SwingConstants.RIGHT );

These simple icons transform the buttons into a diagram of information flow through the GUI. The icons make the users' possible actions clear before they read the buttons' text, enabling new users to understand the buttons' functions at a glance.

The icons in Figure 6 are chosen because they're familiar to most users; similar icons appear on most tape and disk players. "The Java Look and Feel Guidelines, Advanced Topics" illustrate other icons specific to the Java look and feel. Whatever icons are chosen, the program should provide equal margins on the left and right to ensure consistent spacing between the icons and the button text. A slight margin below the icon, as shown in Figure 7, can improve vertical alignment.

Prevent User Errors
One of the best ways to improve usability is to prevent the user from making a mistake. The authors of GUI Design Essentials recommend disabling unavailable actions. This technique guides users through the GUI, preventing them from taking actions that make no sense.

This effective GUI design pattern is trivially easy to code. The ActionListener interface enables the "Add All" and "Remove All" buttons when the lists contain objects, and disables them when the lists are empty.

public void actionPerformed(
  ActionEvent e )
{    .
    .
    .
  _addAll.setEnabled(
   originalModel.getSize() > 0 );
  _removeAll.setEnabled(
   chosenModel.getSize() > 0 );
}

The ListSelectionListener interface enables the "Add" and "Remove" buttons when objects are selected, and disables them when no objects are selected.

public void valueChanged(
   ListSelectionEvent e )
{ _add.setEnabled( _originalList.
   getSelectedValues().length > 0 );
  _remove.setEnabled( _chosenList.
   getSelectedValues().length > 0 );
}

As shown in Listing 1, the ListChooser registers itself as an ActionListener to receive events when buttons are pressed. To receive events when list contents are selected, the ListChooser registers itself as a ListSelectionListener. Also, at the end of the constructor, two dummy events are initiated to set the default enabled states.

public ListChooser(
  Object[] original, Object[] chosen )
{     .
     .
     .
  _originalList.
   addListSelectionListener( this );
  _chosenList.
   addListSelectionListener( this );
  actionPerformed(
   new ActionEvent( this, 0, "" ));
  valueChanged(
   new ListSelectionEvent(
   this, 0, 0, false ));
}

The effect of this code is shown in Figure 8. Rather than trying to deal with the user pressing the wrong button, the program uses disabling to prevent the mistake from occurring. Disabling unavailable actions is one of the simplest and most effective GUI design patterns.

GUI Variations
All of the GUI design patterns described above apply to tables as well as lists. Listing 2 shows an implementation using JTable and TableModel instead of JList and ListModel. "The Java Look and Feel Guidelines" recommend only one table column in the original list and multiple columns in the chosen list. As shown in Listing 2, this can be done by disabling the header and grid lines in the original table, and by assigning the preferred viewport size based on TableColumn widths.

The GridBagLayout code is omitted from Listing 2 as it is similar to the simpler variation of Listing 1. If "Move Up" and "Move Down" buttons are provided, the GridBagLayout contains seven rows instead of five. Following "The Java Look and Feel Guidelines," the spacing between these optional buttons is six pixels greater than between the "Add" and "Remove" buttons.

The ActionListener implementation is slightly different in Listing 2 because of the use of TableModels instead of ListModels. The code in Listing 2 produces the GUI shown in Figure 2.

Details of the JTable and TableModel can be found in The JFC Swing Tutorial (by Kathy Walrath and Mary Campione), along with descriptions of the JList and ListModel. The JTable is more complex than the JList, but when displaying long lists they share many of the same performance issues. A future article will discuss these issues and how to optimize performance for this common GUI design pattern.

Conclusion
The Add-and-Remove pattern enables users to choose multiple objects from long lists. This standard GUI design pattern improves usability by easing the user's learning curve. Standard spacing, directional icons, and button disabling all reduce the users' efforts, enabling them to accomplish their tasks easily in a professional user interface.

Resources

  • Aube, S. (2000). "A Dual Listbox Selection Manager": www.codeguru.com/Cpp/controls/listbox/article.php/c4755
  • Walrath, K., and Campione, M. (2004). The JFC Swing Tutorial: A Guide to Constructing GUIs. Addison-Wesley Professional: java.sun.com/docs/books/tutorial/uiswing/components/
  • "Official Guidelines for User Interface Developers and Designers." Microsoft Inc. (2004): msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwue/html/welcome.asp
  • Sun Microsystems Inc. (2001). Java Look and Feel Design Guidelines, Second Edition. Addison-Wesley Professional: java.sun.com/products/jlf/ed2/book/HIG.Misc.html
  • Sun MicroSystems Inc. (2002). Java Look and Feel Design Guidelines: Advanced Topics. Addison-Wesley Professional: java.sun.com/products/jlf/at/book/Idioms6.html
  • Weinschenk, S., Jamar, P., and Yeo, S. (1997). GUI Design Essentials. John Wiley & Sons.
  • More Stories By Heman Robinson

    Heman Robinson is a senior developer with SAS Institute in Cary, N.C. He holds a BS in mathematics from the University of North Carolina and an MS in computer science from the University of Southern California. He has specialized in GUI design and development for 15 years and has been a Java developer since 1996.

    Comments (1) 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
    steve 02/14/05 07:04:05 PM EST

    Does anyone have code that accomplishes this for VB.NET?

    @ThingsExpo Stories
    SYS-CON Events announced today that Micron Technology, Inc., a global leader in advanced semiconductor systems, will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Micron’s broad portfolio of high-performance memory technologies – including DRAM, NAND and NOR Flash – is the basis for solid state drives, modules, multichip packages and other system solutions. Backed by more than 35 years of technology leadership, Micron's memory solutions enable the world's most innovative computing, consumer,...
    SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies leverage disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevOps to advance innovation and increase agility. Specializing in designing, imple...
    A producer of the first smartphones and tablets, presenter Lee M. Williams will talk about how he is now applying his experience in mobile technology to the design and development of the next generation of Environmental and Sustainability Services at ETwater. In his session at @ThingsExpo, Lee Williams, COO of ETwater, will talk about how he is now applying his experience in mobile technology to the design and development of the next generation of Environmental and Sustainability Services at ETwater.
    While many app developers are comfortable building apps for the smartphone, there is a whole new world out there. In his session at @ThingsExpo, Narayan Sainaney, Co-founder and CTO of Mojio, will discuss how the business case for connected car apps is growing and, with open platform companies having already done the heavy lifting, there really is no barrier to entry.
    SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
    As more and more data is generated from a variety of connected devices, the need to get insights from this data and predict future behavior and trends is increasingly essential for businesses. Real-time stream processing is needed in a variety of different industries such as Manufacturing, Oil and Gas, Automobile, Finance, Online Retail, Smart Grids, and Healthcare. Azure Stream Analytics is a fully managed distributed stream computation service that provides low latency, scalable processing of streaming data in the cloud with an enterprise grade SLA. It features built-in integration with Azur...
    As more intelligent IoT applications shift into gear, they’re merging into the ever-increasing traffic flow of the Internet. It won’t be long before we experience bottlenecks, as IoT traffic peaks during rush hours. Organizations that are unprepared will find themselves by the side of the road unable to cross back into the fast lane. As billions of new devices begin to communicate and exchange data – will your infrastructure be scalable enough to handle this new interconnected world?
    WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
    Through WebRTC, audio and video communications are being embedded more easily than ever into applications, helping carriers, enterprises and independent software vendors deliver greater functionality to their end users. With today’s business world increasingly focused on outcomes, users’ growing calls for ease of use, and businesses craving smarter, tighter integration, what’s the next step in delivering a richer, more immersive experience? That richer, more fully integrated experience comes about through a Communications Platform as a Service which allows for messaging, screen sharing, video...
    SYS-CON Events announced today that IceWarp will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. IceWarp, the leader of cloud and on-premise messaging, delivers secured email, chat, documents, conferencing and collaboration to today's mobile workforce, all in one unified interface
    The Internet of Things (IoT) is about the digitization of physical assets including sensors, devices, machines, gateways, and the network. It creates possibilities for significant value creation and new revenue generating business models via data democratization and ubiquitous analytics across IoT networks. The explosion of data in all forms in IoT requires a more robust and broader lens in order to enable smarter timely actions and better outcomes. Business operations become the key driver of IoT applications and projects. Business operations, IT, and data scientists need advanced analytics t...
    With the proliferation of connected devices underpinning new Internet of Things systems, Brandon Schulz, Director of Luxoft IoT – Retail, will be looking at the transformation of the retail customer experience in brick and mortar stores in his session at @ThingsExpo. Questions he will address include: Will beacons drop to the wayside like QR codes, or be a proximity-based profit driver? How will the customer experience change in stores of all types when everything can be instrumented and analyzed? As an area of investment, how might a retail company move towards an innovation methodolo...
    Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome,” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
    Consumer IoT applications provide data about the user that just doesn’t exist in traditional PC or mobile web applications. This rich data, or “context,” enables the highly personalized consumer experiences that characterize many consumer IoT apps. This same data is also providing brands with unprecedented insight into how their connected products are being used, while, at the same time, powering highly targeted engagement and marketing opportunities. In his session at @ThingsExpo, Nathan Treloar, President and COO of Bebaio, will explore examples of brands transforming their businesses by t...
    Akana has announced the availability of the new Akana Healthcare Solution. The API-driven solution helps healthcare organizations accelerate their transition to being secure, digitally interoperable businesses. It leverages the Health Level Seven International Fast Healthcare Interoperability Resources (HL7 FHIR) standard to enable broader business use of medical data. Akana developed the Healthcare Solution in response to healthcare businesses that want to increase electronic, multi-device access to health records while reducing operating costs and complying with government regulations.
    For IoT to grow as quickly as analyst firms’ project, a lot is going to fall on developers to quickly bring applications to market. But the lack of a standard development platform threatens to slow growth and make application development more time consuming and costly, much like we’ve seen in the mobile space. In his session at @ThingsExpo, Mike Weiner, Product Manager of the Omega DevCloud with KORE Telematics Inc., discussed the evolving requirements for developers as IoT matures and conducted a live demonstration of how quickly application development can happen when the need to comply wit...
    The Internet of Everything (IoE) brings together people, process, data and things to make networked connections more relevant and valuable than ever before – transforming information into knowledge and knowledge into wisdom. IoE creates new capabilities, richer experiences, and unprecedented opportunities to improve business and government operations, decision making and mission support capabilities.
    Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at @ThingsExpo, James Kirkland, Red Hat's Chief Architect for the Internet of Things and Intelligent Systems, described how to revolutionize your archit...
    MuleSoft has announced the findings of its 2015 Connectivity Benchmark Report on the adoption and business impact of APIs. The findings suggest traditional businesses are quickly evolving into "composable enterprises" built out of hundreds of connected software services, applications and devices. Most are embracing the Internet of Things (IoT) and microservices technologies like Docker. A majority are integrating wearables, like smart watches, and more than half plan to generate revenue with APIs within the next year.
    Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Opening Keynote at 16th Cloud Expo, Sandy Carter, IBM General Manager Cloud Ecosystem and Developers, and a Social Business Evangelist, d...