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Jon Bradley
Software Engineer |
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he new BASIS IDE component, AppBuilder, has arrived. Debuting in BBj® 6.0 and coupled with the IDE’s GUI screen design tool,
FormBuilder, AppBuilder provides a much-anticipated cross-platform graphical application development tool. AppBuilder provides
all the functionality BBx® developers know and love from GUIBuilder, but with a more intuitively designed interface delivering
what you see is what you get (WYSIWYG) functionality. Figure 1 shows a standard AppBuilder screen in all its
glory.
AppBuilder makes it easier and faster to create graphical user interface (GUI) applications. A typical GUI program has many
elements.
- Initialization
- Specification of what controls and windows the GUI shall display
- Specification of what user actions cause the execution of event handlers
- Event loop
- Error and escape handling
- Cleanup
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Figure 1. The AppBuilder desktop |
AppBuilder makes development a snap by writing the general framework, often called the boilerplate code, which varies very
little from application to application. By integrating tightly with FormBuilder, AppBuilder
is a great tool for developing GUI resources and specifying what controls and windows display when the application runs. With
FormBuilder and AppBuilder, the BASIS IDE allows the developer to edit the resource file while also specifying what the
program does when the user interacts with those controls in a given way. By writing all the boilerplate code, AppBuilder
reduces the difficulty and time required to write a BBj GUI program. In addition, AppBuilder only displays the
developer-specified event handling code and drastically reduces the amount of code a developer wades through while working on
the application.
GUIBuilder Turbo Charged
AppBuilder is a functional replacement for GUIBuilder, BASIS’ previous application development tool. The tight integration
with FormBuilder and more intuitive interface are AppBuilder’s primary advantages over GUIBuilder. The developer can now edit
the resource and navigate through the event handling code blocks visually via the integration and coordination between the FormEditor, BBjGui Inspector, and Code Editor shown in
Figure 2.
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Figure 2. FormBuilder's Form Editor (blue outline) and AppBuilder’s Code Editor (red outline) |
Immediately after adding a control via the FormBuilder palette, AppBuilder’s Code Editor displays the available and registered
events. In addition to listing the events, the Code Editor provides a syntax-colored, code completion-enabled editor for
editing a given event’s code block.
The BBjGui Inspector component displays and navigates the registered events and controls within the application in a tree
format (see Figure 3). Non-event specific code blocks, such as the Init block, are listed as well.
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Figure 3. BBjGui inspector |
In addition to the updated graphical interface, AppBuilder provides several useful enhancements over GUIBuilder. Like many
modern applications, pressing [F1] opens up context-sensitive help. Code completion further reduces reliance on external
documentation by providing the developer with the method signatures for the BBjAPI objects on demand.
Automatically Inserting Commonly Used Code
Registering an event adds some default code for that event as specified by the Default Code Profile (see Figure 4).
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Figure 4. Default Code Profile dialog box |
In addition to being able to configure what code AppBuilder inserts automatically when the developer registers for an event,
the developer can configure the default code profiles to register automatically for specific events upon the addition of
controls (see Figure 5).
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Figure 5. Profile Management dialog box
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AppBuilder Additions to GUIBuilder Functionality
AppBuilder optionally utilizes a pre-processor to provide developers a chance to modify the AppBuilder file also known as a
.gbf file. The pre-processor can easily perform string literal substitutions as shown in
Figure 6.
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Figure 6. Sample string literal substitutions
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Compatibility and a Look Towards the Future
Existing .gbf files created by GUIBuilder can be loaded directly in AppBuilder. AppBuilder is
backwardly compatible with GUIBuilder and, therefore, Visual PRO/5® as it generates the same READ RECORD code as
GUIBuilder. Since the language has progressed significantly since the introduction of GUIBuilder in 1998, BASIS plans to add a
wizard for generating a GUI application from a defined record set. At a later date BASIS will update AppBuilder with the
capability of generating modern code including event objects, callback event dispatching, and AppBuilder custom objects. This
will provide developers a choice between backwards compatibility or the use of the powerful new language features.
Summary
By providing a cross-platform application development tool integrated within the IDE, BASIS continues to improve developers’
programming experience. By generating and hiding the boilerplate code, AppBuilder makes creating GUI applications faster and
less repetitive. The integrated interface for defining GUI resources along with their behavior makes programming more
intuitive. The addition of syntax coloring and code completion reduces programmer errors, and reduces reliance on
documentation. Give AppBuilder a try, and see how it improves developer productivity, and how “easily” the development process
unfolds
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