Jigloo: The GUI Plug-in for Eclipse

Jigloo is an Eclipse plug-in that enables you to build sophisticated graphical user interfaces (GUIs) for applications to run on Java platform. It has been made by CloudGarden for building user interfaces using Swing or SWT. It is available for free for non-commercial use whereas a professional license can be obtained from CloudGarden for commercial usage.

When Java was conceived, AWT was Java's UI library for building desktop applications. Later with JDK 1.2 release, Swing was introduced, which provided a much better and sophisticated look and feel for GUIs. SWT is a competing Open Source Java GUI toolkit comprising a widget set and a UI library that builds GUIs with the look and feel of the native desktop applications. One main advantage of SWT over Swing is that it is faster, more responsive and lighter on system resource usage. Now with Jigloo you can rapidly build user interfaces targeting Swing or SWT.

Features
Jigloo is a WYSIWYG editor for building Swing and SWT user interfaces. It creates and manages code for all the parts of Swing or SWT GUIs as well as code to handle events. It supports round-tripping also, which means you can make visual changes that cause the underlying code to change but you can also directly apply changes to code and see the changes being reflected in the GUI. It is compatible with both swing and SWT, and so can be used to convert between both. It has support to handle most of Swing and SWT layouts, and also creates Event-Handlers for the components of the GUI. Let's see how well Jigloo works with Eclipse.

Setting up

We have provided Jigloo on this month's DVD. Just extract the Jigloo_395 zip file and move the folder ?plugins\ com. cloudgarden.jigloo_3.9.5? to the Plugins folder under Eclipse directory and also move ?features\com.cloudgarden. jigloo_3.9.5? to the Features folder under Eclipse directory. Now just start Eclipse and Jigloo is ready to be used.

To create a demo application explore the functionalities of the plug-in. Select File > New > Project, and after selecting the Java Project proceed further by clicking on the Next button. This will get us to the New Project dialog box. Let's name our project as PCQDemo. We will make an SWT based application. For this some extra configuration needs to be done. First we need to add SWT jar to project's classpath. To do that select PCQDemo project and right-click, select Properties from the menu. This will bring Project Properties window, whereby selecting Java Build Path on left navigation will bring up Java Build Path dialog on the right frame. Here click on Libraries tab and then on Add External jars button. This will bring up a File Explorer dialog. Navigate to Plugins folder under Eclipse installation directory. Look for org.eclipse.swt.X.X.X.jar. The X.X.X will be different depending on what platform that's being used. Select that jar file and click Open, then click OK. And, our Java Project has been created with SWT library added to its classpath.

Working with GUI
To start working with the GUI for our application, let's create a package namely com.pcqlabs.Jigloo. Right-click on the Package and select New > Other which will bring up ?Select a Wizard? screen. All Jigloo wizards can be found under GUI Forms folder. Open the subfolder SWT. Select SWT Main Application option as shown in figure. Clicking Next there and on ?Create a new SWTApp? screen, we name the class and proceed with the GUI builder.

The view that opens up is a split view with visual design window above and below its editor window. We see that Jigloo already has created a lot of code. Along that a new package has been created with name com.cloudspace.resource. This package contains generated class SWTResourceManager. As the name implies, this class contains SWT resource such as fonts, colors and images. Jigloo provides liberty to change the SWTResourceManager for changing settings for the fonts or colors that will be used by the application.

Let's start using the visual designer. It has a toolbar on the top, which contains various visual components for the application. From the Controls tab we can directly drag/drop the controls over the container. Let's place two labels, two textboxes and a button. The GUI Properties tab shows the properties that are related to the selected component on the container. The values set here get reflected on the code and the visual design on the fly. The toolbar also has tabs for containers, whereby containers for the application could be selected. Similarly the Layout tab allows selecting the layout that we want to choose. The left bar of the visual designer has various alignment options and with these the controls on the container can be aligned.
Jigloo also makes the event handling for the components easy. You just have to select the component for which you want to write the event, and then under the Events tab select the appropriate listener and then its handler. In our case we will select the button and mouse event listener for the Submit button.

Lastly, we can also preview the UI by clicking the Preview option on the right panel.

Conclusion
For Java developers, Jigloo can lead to substantial time savings, as it offers GUI to perform development and maintenance tasks, easily.