GUI Building in NetBeans IDE 5.0
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This tutorial guides you through the process of creating the graphical
user interface (GUI) for an application called ContactEditor. In the
process you will layout a GUI front-end that enables you to view and
edit contact information of individuals included in an employee database.
In this tutorial you will learn how to:
- Use the GUI Builder Interface
- Create a GUI Container
- Add Components
- Resize Components
- Align Components
- Adjust Component Anchoring
- Set Component Auto-Resizing Behavior
- Edit Component Properties
This tutorial takes about 30 minutes to complete.
Note: Wherever you see the
icon, you can click to view a detailed interactive demonstration of GUI
Builder functionality.
Getting Started
As of NetBeans 5.0, the IDE's GUI Builder has been revamped to make it more
powerful and intuitive, liberating users to build professional-looking GUIs
without an intimate understanding of layout managers.
NetBeans' new GUI Builder eliminates the difficulties of building GUIs, enabling
you to lay out your forms by simply placing components where you want
them.
Creating a Project
Because all Java development in the IDE takes place within projects, we first
need to create a new ContactEditor project within which to store sources and other
project files. An IDE project is a group of Java source files plus its associated
meta data, including project-specific properties files, an Ant build script
that controls the build and run settings, and a project.xml file that maps
Ant targets to IDE commands. While Java applications often consist of
several IDE projects, for the purposes of this tutorial, we will build a simple
application which is stored entirely in a single project.
To create a new ContactEditor application project:
- Choose File > New
Project. Alternately, you can click the New Project icon
in the IDE toolbar.
- In the Categories pane, select the General node and in the Projects
pane, choose Java Application. Click Next.
- Enter ContactEditor in the Project Name field and specify the project
location.
- Ensure that the Set as Main Project checkbox is selected and
deselect Create Main Class if it is selected.
- Click Finish.
The IDE creates the ContactEditor folder on your system in
the designated location. This folder contains all of the project's associated
files, including its Ant script, folders for storing sources and tests,
and a folder for project-specific metadata. To view the project structure,
use the IDE's Files window.
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Creating a GUI Container
After creating the new application, you may have noticed that the Source
Packages folder in the Projects window contains an empty <default package> node.
To proceed with building our interface, we need to create a Java container
within which we will place the other required GUI components. In this step
we'll create a container using the JFrame component and place the
container in a new package.
To create a JFrame container:
- In the Projects window, right-click the ContactEditor node and choose
New > JFrame Form.
- Enter ContactEditorUI as the Class Name.
- Enter my.contacteditor as the package.
- Click Finish.
The IDE creates the ContactEditorUI form and the ContactEditorUI class
within the ContactEditorUI.java application and opens the ContactEditorUI form in the GUI Builder. Notice that the my.contacteditor package
form in the GUI Builder. Notice that the my.contacteditor
package replaces the default package.
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Getting Familiar with the GUI Builder
Now that we've set up a new project for our application, let's take
a minute to familiarize ourselves with the GUI Builder's interface.
To explore the GUI Builder interface with an interactive demo, click
the View Demo icon.

View Demo
When we added the JFrame container, the IDE opened the newly-created ContactEditorUI form
in an Editor tab with a toolbar containing several
buttons, as shown in the preceeding illustration. The ContactEditor form
opened in the GUI Builder's Design view and three additional windows
appeared automatically along the IDE's edges,
enabling you to navigate, organize, and edit GUI forms as you build
them.
The GUI Builder's various windows include:
- Design Area. The GUI Builder's primary window for creating
and editing Java GUI forms. The toolbar's Source and Design toggle
buttons enable you to view a class's source code or a graphical
view of its GUI components. The
additional toolbar buttons provide convenient access to common commands,
such as choosing between Selection and Connection modes, aligning
components, setting component auto-resizing behavior, and previewing
forms.
- Inspector. Provides a representation of all the components,
both visual and non-visual, in your application as a tree hierarchy.
The Inspector also provides visual feedback about what component in
the tree is currently being edited in the GUI Builder as well as allows
you to organize components in the available panels.
- Palette. A customizable list of available components
containing tabs for JFC/Swing, AWT, and JavaBeans components, as well
as layout managers. In addition, you can create, remove, and rearrange
the categories displayed in the Palette using the customizer.
- Properties Window. Displays the properties of the component
currently selected in the GUI Builder, Inspector window, Projects window
or Files window.
If you click the Source button, the IDE displays the application's Java source
code in the Editor with sections of code that are automatically generated
by the GUI Builder indicated by blue areas, called Guarded Blocks. Guarded
Blocks are protected areas that are not editable in Source view. You can only
edit code appearing in the white areas of the Editor when in Source view.
If you need to make changes to the code within a Guarded Block, clicking the
Design button returns the IDE's Editor to the GUI Builder where you can make
the necessary adjustments to the form. When you save your changes the IDE
updates the file's sources.
Note: For advanced developers, a Palette Customizer is available
that enables you to add custom components from JARs, libraries, or
other projects to the Palette.
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Key Concepts
The IDE's GUI Builder solves the core problem of Java GUI creation by streamlining
the workflow of creating graphical interfaces, freeing developers from the complexities
of Swing layout managers. It does this by extending the current NetBeans IDE
GUI Builder to support a straightforward "Free Design" paradigm with
simple layout rules that are easy to understand and use. As you lay out your
form, the GUI Builder provides visual guidelines suggesting optimal spacing
and alignment of components. In the background, the GUI Builder translates your
design decisions into a functional UI that is implemented using the new GroupLayout
layout manager and other Swing constructs. Because it uses a dynamic layout
model, GUI's built with the GUI Builder behave as you would expect at runtime,
adjusting to accommodate any changes you make without altering the defined
relationships between components. Whenever you resize the form, switch
locales, or specify a different look and feel, your GUI automatically
adjusts to respect the target look and feel's insets and offsets.
Free Design
In the IDE's GUI Builder, you
can build your forms by simply putting components where you want them
as though you were using absolute positioning. The GUI Builder
figures out which layout managers are required and then generates the code for
you automatically. You need not concern yourself with insets, anchors,
fills, and so forth. When deploying your applications, you can ensure
they behave as expected by packaging the freely distributable JAR file
of updated Swing libraries that is included.
Automatic Component Positioning (Snapping)
As you add components to a form, the GUI Builder provides visual feedback
that assists in positioning components based on your operating system's
look and feel. The GUI Builder provides helpful inline hints and other visual
feedback regarding where components should be placed on your form, automatically
snapping components into position along guidelines. It makes these suggestions
based on the positions of the components that have already been placed in
the form, while allowing the padding to remain flexible such that different
target look and feels render properly at runtime.
Visual Feedback
The GUI Builder also provides visual feedback regarding component anchoring
and chaining relationships. These indicators enable you to quickly identify the
various positioning relationships and component pinning behavior that affect
the way your GUI will both appear and behave at runtime. This speeds the GUI design process,
enabling you to quickly create professional-looking visual interfaces
that work.
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First Things First
Now that you have familiarized yourself with the GUI builder's
interface, it's time to begin developing the UI of our ContactEditor
application. In this section we'll take a look at using the IDE's Palette
to add the various GUI components we need to our form.
Thanks to NetBeans 5.0's Free Design paradigm, you no longer have to struggle
with layout managers to control the size and position of the components within
your containers. All you need to do is drag and drop (or pick and plop) the
components you need to your GUI form as shown in the illustrations that follow.
Adding Components: The Basics
Though the IDE's GUI Builder simplifies the process of creating Java
GUIs, it is often helpful to sketch out the way you want
your interface to look before beginning to lay it out. Many interface designers
consider this a "best practice" technique, however, for the purposes
of this tutorial you can simply peek at how our completed form should look
by jumping ahead to the Previewing
your GUI section.
Since we've already added a JFrame as our form's top-level container,
the next step is to add a couple of JPanels which will enable us
to cluster the components of our UI using titled borders. Refer
to the following illustrations and notice the IDE's "pick and plop" behavior
when accomplishing this.
To add a JPanel:
- In the Palette window, select the JPanel component
from the Swing category by clicking and releasing the mouse button.
- Move the cursor to the upper left corner of the form
in the GUI Builder. When the component is located near the
container's top and left edges, horizontal and vertical alignment
guidelines appear indicating the preferred margins. Click
in the form to place the JPanel in this location.
The JPanel component appears in the ContactEditorUI form
with orange highlighting signifying that it is selected,
as shown in the following illustration. After releasing the mouse button, small indicators appear
to show the component's anchoring relationships and a corresponding
JPanel node is displayed in the Inspector window.
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Next, we need to resize the JPanel to make room for the components
we'll place within it a little later, but let's take a minute to
point out another of the GUI Builder's visualization features first.
In order to do this we need to deselect the JPanel we just added.
Because we haven't added a title border yet, the panel disappears.
Notice, however, that when you pass the cursor over the JPanel,
its edges change to light gray so that its position can be clearly
seen. You need only to click anywhere within the component to reselect
it and cause the resize handles and anchoring indicators to reappear.
To resize the JPanel:
- Select the JPanel you just added. The small square
resize handles reappear around the component's perimeter.
- Click and hold the resize handle on the right edge of the JPanel and
drag until the dotted alignment guideline appears near the
form's edge.
- Release the resize handle to resize the component.
The JPanel component is extended to span between
the container's left and right margins in accordance with
the recommended offset, as shown in the following illustration.
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Now that we've added a panel to contain our UI's Name information,
we need to repeat the process to add another directly below the
first for the E-mail information. Refering to the following illustrations,
repeat the previous two tasks, paying attention to the
GUI Builder's suggested positioning. Notice that the suggested
vertical spacing between the two JPanels is much narrower than
that at the edges. Once you have added the second JPanel, resize it such that it
fills the form's remaining vertical space.
Because we want to visually distinguish the functions in the upper and lower sections
of our GUI, we need to add a border and title to each JPanel. First we'll accomplish
this using the Properties window and then we'll try it using the pop-up menu.
To add title borders to the JPanels:
- Select the top JPanel in the GUI Builder.
- In the Properties window, click the ellipsis button (...) next to the
Border property.
- In the JPanel Border editor that appears, select the TitledBorder node
in the Available Borders pane.
- In the Properties pane below, enter Name for the Title property.
- Click the ellipsis (...) next to the Font property, select Bold for
the Font Style, and enter 12 for the Size. Click OK to exit the dialogs.
- Select the bottom JPanel and repeat steps 2 through 5,
but this time right-click the JPanel and access the Properties
window using the pop-up menu. Enter E-mail for the
Title property.
Titled borders are added to both JPanel components.
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To view a demonstration of the previous procedure, click
View Demo
Adding Individual Components to the Form
Now we need to start adding the components that will actually
present the actual contact information in our contact list. In
this task we'll add four JTextFields that will display the contact
information and the JLabels that will describe them. While accomplishing
this, notice the horizontal and vertical guidelines that the GUI
Builder displays, suggesting the preferred component spacing as
defined by your operating system's look and feel. This ensures that
your GUI is automatically rendered respecting the target operating system's
look and feel at runtime.
To add a JLabel to the form:
- In the Palette window, select the JLabel component from the Swing
category.
- Move the cursor over the Name JPanel we added earlier. When
the guidelines appear indicating that the JLabel is positioned in the
top left corner of the JPanel with a small margin at the top and left
edges, click to place the label.
The JLabel is added to the form and a corresponding node representing
the component is added to the Inspector window.
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Before going further, we need to edit the display text of the
JLabel we just added. Though you can edit component display text
at any point, the easiest way is to do this as you add them.
To edit the display text of a JLabel:
- Double-click the JLabel to select its display text.
- Type First Name: and press Enter.
The JLabel's new name is displayed and the component's width adjusts
as a result of the edit.
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Now we'll add a JTextField so we can get a glimpse of the
GUI Builder's baseline alignment feature.
To add a JTextField to the form:
- In the Palette window, select the JTextField component from
the Swing category.
- Move the cursor immediately to the right of the First Name:
JLabel we just added.
When the horizontal guideline appears indicating that the JTextField's
baseline is aligned with that of the JLabel and the spacing
between the two components is suggested with a vertical guideline,
click to position the JTextField.
The JTextField snaps into position in the form aligned with
the JLabel's baseline, as shown in the following illustration.
Notice that the JLabel shifted downward slightly in order to
align with the taller text field's baseline. As usual, a node
representing the component is added to the Inspector window.
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Before proceeding further, we need to add an additional
JLabel and JTextField immediately to the right of those we just added,
as shown in the following illustration.
This time enter Last Name: as the JLabel's display text
and leave the JTextFields' placeholder text as it
is for now.
To resize a JTextField:
- Select the JTextField we just added to the right of the Last Name: JLabel.
- Drag the JTextField's right edge resize handle
toward the right of the enclosing JPanel.
- When the vertical alignment guidelines appear suggesting the margin
between the text field and and right edge of the JPanel, release the mouse
button to resize the JTextField.
The JTextField's right edge snaps into alignment with
the JPanel's recommended edge margin, as
shown in the following illustration.
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To view a demonstration of the previous procedure, click
View Demo
Adding Multiple Components to the Form
Now we'll add the Title: and Nickname: JLabels
that describe two JTextFields we're going to add in a minute.
We'll pick and plop the components while pressing the Shift key,
to quickly add them to the form. While accomplishing this, again
notice that the GUI Builder displays horizontal and vertical guidelines
suggesting the preferred component spacing.
To add multiple JLabels to the form:
- In the Palette window, select the JLabel component from the Swing
category by clicking and releasing the mouse button.
- Move the cursor over the form directly below the First Name: JLabel
we added earlier. When the guidelines appear indicating that the new
JLabel's left edge is aligned with that of the JLabel above and a small
margin exists between them, shift-click to place the first JLabel.
- While still pressing the Shift key, click to place another
JLabel immediately to the right of the first. Make certain to
release the Shift key prior to positioning the second JLabel.
If you forget to release the Shift key prior to positioning
the last JLabel, simply press the Escape key.
The JLabels are added to the form creating a second row, as
shown in the following illustration. Nodes representing
each component are added to the Inspector window.
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Before moving on, we need to edit the JLabels' name so that we'll
be able to see the effect of the alignments we'll set later.
To edit the display text of JLabels:
- Double-click the first JLabel to select its display text.
- Type Title: and press Enter.
- Repeat steps 1 and 2, entering Nickname: for the second JLabel's
name property.
The JLabels' new names are displayed in the form and
are shifted as a result of their edited widths, as shown
in the following illustration.
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To view a demonstration of the previous procedure, click
View Demo
Inserting Components
Often it is necessary to add a component between components that
are already placed in a form. Whenever you add a component between
two existing components, the GUI Builder automatically shifts
them to make room for the new component. To demonstrate this,
we'll insert a JTextField between the JLabels we added previously,
as shown in the following two illustrations.
To insert a JTextField between two JLabels:
- In the Palette window, select the JTextField component from the Swing
category.
- Move the cursor over the Title: and Nickname: JLabels
on the second row such that the JTextField overlaps both and
is aligned to their baselines. If you encounter difficulty
positioning the new text field, you can snap it to the left
guideline of the Nickname JLabel as shown in the first
image below.
- Click to place the JTextField between the Title: and Nickname: JLabels.
The JTextField snaps into position between the two JLabels. The
rightmost JLabel shifts toward the right of the JTextField
to accommodate the
suggested horizontal offset.
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We still need to add one additional JTextField to the form that
will display each contacts' Nickname on the right side of the form.
To add a JTextField:
- In the Palette window, select the JTextField component from the Swing
category.
- Move the cursor to the right of the Nickname label and click to place
the text field.
The JTextField snaps into position next to the JLabel on its left.
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To resize a JTextField:
- Drag the resize handles of the Nickname: label's JTextField
you added in the previous task toward the right of the enclosing
JPanel.
- When the vertical alignment guidelines appear suggesting the margin
between the text field and JPanel edges, release the mouse
button to resize the JTextField.
The JTextField's right edge snaps into alignment with the JPanel's
recommended edge margin and
the GUI Builder infers the appropriate resizing behavior.
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To view a demonstration of the previous procedure, click
View Demo
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Moving Forward
Alignment is one of the most fundamental aspects of creating professional-looking
GUIs. In the
previous section we got a glimpse of the IDE's alignment features while adding
the JLabel and JTextField components to our ContactEditorUI form. Next we'll
take a more in depth look at the GUI Builder's alignment features as we work
with the various other components we need for our application.
Component Alignment
Every time
you add a component to a form, the GUI Builder effectively aligns
them, as evidenced by the alignment guidelines that appear. It
is sometimes necessary, however, to specify different relationships
between groups of components as well. Earlier we added four JLabels
we need for our ContactEditor GUI, but we didn't align them. Now
we'll align the two columns of JLabels so that their right edges
line up.
To align components:
- Select the First Name: and Title: JLabels on the left
side of the form.
- Click the Align Right in Column button
(
) in the toolbar. Alternately, you can right-click
one and choose Align > Right in Column from the pop-up menu.
- Repeat this for the Last Name: and Nickname: JLabels
as well.
The JLabels' positions shift such that the right edges of their display
text are aligned. The anchoring relationships are updated, indicating that
the components have been grouped.
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Before we're finished with the JTextFields we added earlier, we
need to make sure that the two JTextFields we inserted between
the JLabels are set to resize correctly. Unlike the two JTextFields
that we stretched to the right edge of our form, inserted components'
resizeability behavior isn't automatically set.
To set component resizeability behavior:
- Control-click the two inserted JTextField components
to select them in the GUI Builder.
- With both JTextFields selected, right-click either one of them and choose
Auto Resizing > Horizontal from the pop-up menu.
The JTextFields are set to resize horizontally at runtime. The
alignment guidelines and anchoring indicators are updated providing
visual feedback of the component relationships.
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To set components to be the same size:
- Control-click all four of the JTextFields in the form to select them.
- With the JTextFields selected, right-click any one of them and choose
Set Default Size from the pop-up menu.
The JTextFields are all set to the same width and
indicators are added to the top edge of each, providing visual
feedback of the component relationships.
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Now we need to add another JLabel describing the JComboBox that will enable
users to select the format of the information our ContactEditor application will
display.
To align a JLabel to a component group:
- In the Palette window, select the JLabel component from the
Swing category.
- Move the cursor below the First Name and Title JLabels
on the left side of the JPanel. When the guideline
appears indicating that the new JLabel's right edge is aligned
with the right edges of the component group above (the two
JLabels), click to position the component.
The JLabel snaps into a right-aligned position with the column
of JLabels above, as shown in the following illustration.
The GUI Builder updates the alignment status lines indicating
the component's spacing and anchoring relationships.
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As in the previous examples, double-click the JLabel to select its display
text and then enter Display
Format: for the display name. Notice that when the JLabel snaps into position,
the other components shift to accommodate the longer display text.
To view a demonstration of the previous procedure, click
View Demo
Baseline Alignment
Whenever you add or move components that include text
(JLabels, JTextFields, and so forth), the IDE suggests alignments which
are based on the baselines of the text in the components. When we
inserted the JTextField earlier, for example, its baseline was automatically
aligned to the adjacent JLabels.
Now we'll add the combo box that will enable users to select the
format of the information that our ContactEditor application will display.
As we add the JComboBox, we'll align its baseline to that of the
JLabel's text. Notice once again the baseline alignment guidelines
that appear to assist us with the positioning.
To align the baselines of components:
- In the Palette window, select the JComboBox component from
the Swing category.
- Move the cursor immediately to the right of the JLabel we
just added. When the horizontal guideline appears indicating
that the JComboBox's baseline is aligned with the baseline
of the text in the JLabel and the spacing between the two components
is suggested with a vertical guideline, click to position the
combo box.
The component snaps into
a position aligned with the baseline of the JLabel to its left,
as shown in the following illustration. The GUI Builder displays
status lines indicating the component's spacing and anchoring
relationships.
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To resize the JComboBox:
- Select the JComboBox in the GUI Builder.
- Drag the resize handle on the JComboBox's right edge
toward the right until the alignment guidelines appear suggesting
the preferred offset between the JComboBox and JPanel edges.
As shown in the following illustration, the JComboBox's
right edge snaps into alignment with the JPanel's recommended
edge margin and the component's width is automatically set
to resize with the form.
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Editing component models is beyond the scope of this tutorial,
so for the time being, we'll leave the JComboBox's placeholder item list
as it is.
To view a demonstration of the previous procedure, click
View Demo
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Reviewing What We've Learned
We've gotten off to a good start building our ContactEditor GUI, but
let's take a minute to recap what we've learned while we add a few
more of the components our interface requires.
Until now we've concentrated on adding components
to our ContactEditor GUI using the IDE's alignment guidelines
to help us with positioning. It is important to understand, however,
that another integral part of component placement is anchoring. Though
we haven't discussed it yet, you've already taken advantage of this
feature without realizing it. As mentioned previously, whenever you
add a component to a form, the IDE suggests the target look and feel's
preferred positioning with guidelines. Once placed, new components are
also anchored to the nearest container edge or component in order to
ensure that component relationships are maintained at runtime. In this
section we'll concentrate on accomplishing the tasks in a more streamlined
fashion while pointing out the work the GUI builder is doing behind
the scenes.
Adding, Aligning, and Anchoring
The GUI Builder enables you to layout your forms quickly and easily
by streamlining typical workflow gestures. Whenever
you add a component to a form, the GUI Builder automatically snaps
them into the preferred positions and sets the necessary
chaining relationships so you can concentrate on designing your
forms rather than struggling with complicated implementation details.
To add, align, and edit the display text of a JLabel:
- In the Palette window, select the JLabel component from the Swing category.
- Move the cursor over the form immediately below the bottom JPanel's
E-mail title. When the guidelines appear indicating that it's
positioned in the top left corner of the JPanel with a small
margin at the top and left edges, click to place the JLabel.
- Double-click the JLabel to select its display text. Then type Email
Address: and press Enter.
The JLabel snaps into the preferred position in the form, anchored to
the top and left edges of the enclosing JPanel.
Just as before, a corresponding node representing the component is
added to the Inspector window.
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To add a JTextField:
- In the Palette window, select the JTextField component from the Swing
category.
- Move the cursor immediately to the right of the E-mail Address label
we just added. When the guidelines appear indicating that the JTextField's
baseline is aligned with the baseline of the text in the JLabel and the
margin between the two components is suggested with a vertical guideline,
click to position the text field.
The JTextField snaps into position on the right of the E-mail Address: JLabel
and is chained to the JLabel. Its corresponding node is also added to the
Inspector window.
- Drag the resize handle of the JTextField toward the right of the enclosing
JPanel until the alignment guidelines appear suggesting the offset between
the JTextField and JPanel edges.
The JTextField's right edge snaps to the alignment guideline indicating
the preferred margins.
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Now we need to add the JList that will display our ContactEditor's entire contact list.
To add and resize a JList:
- In the Palette window, select the JList component from
the Swing category.
- Move the cursor immediately below the E-mail Address JLabel
we added earlier. When the guidelines appear indicating that
the JList's top and left edges are aligned with the preferred
margins along the JPanel's left edge and
the JLabel above, click to position the JList.
- Drag the JList's right resize handle toward the right of the enclosing
JPanel until the alignment guidelines appear indicating that
it is the same width as the JTextField
above.
The JList snaps into the position designated by the alignment
guidelines and its corresponding node is displayed in the
Inspector window. Notice also that the form expands to accommodate
the newly added JList.
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Since JLists are used to display long lists of data, they typically
require the addition of a JScrollPane. Whenever you add a component which requires a JScrollPane,
the GUI Builder automatically adds it for you. Because JScrollPanes are non-visual
components, you have to use the Inspector window in order to view or edit any
JScrollPanes that the GUI Builder created.
To view a demonstration of the previous procedure, click
View Demo
Component Sizing
It is often beneficial to set several related components, such
as buttons in modal dialogues, to be the same size for visual
consistency. To demonstrate this we'll add four JButtons
to our ContactEditor form that will allow us to add, edit, and
remove individual entries from our contact list, as shown in the
following illustrations. Afterwards, we'll set the four buttons to
be the same size so they can be easily recognized as offering
related functionality.
To add, align, and edit the display text of multiple buttons:
- In the Palette window, select the JButton component.
- Move the JButton over the right edge of the E-mail Address JTextField
in the lower JPanel. When the guidelines appear indicating that
the JButton's baseline and right edge are aligned with that
of the JTextField, shift-click to place the first button along
the JFrame's right edge. The JTextField's width shrinks to
accommodate the JButton when you release the mouse button.
- Move the cursor over the top right corner of the JList in the lower
JPanel. When the guidelines appear indicating that the JButton's top
and right edges are aligned with that of the JList, shift-click to place
the second button along the JFrame's right edge.
- Add two additional JButtons below the two we already added
to create a column. Make certain to position the JButtons such
that the suggested spacing is respected and consistent. If
you forget to release the Shift key prior to positioning
the last JButton, simply press the Escape key.
- Double-click each JButton and enter the text for each of their names.
Enter
Add for the top button, Edit for the
second, Remove for the third, and As Default for
the fourth.
The JButton components snap into the positions designated by the alignment
guidelines. The width of the buttons changes to accommodate the
new names.
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Now that the buttons are positioned where we want them, we'll set
the four buttons to be the same size for visual consistency as
well as to clarify that they are related functionally.
To set components to the same size:
- Select all four JButtons by pressing the Control key while making your selection.
- Right-click any one of them, and choose Same Size > Same
Width from the pop-up menu.
The JButtons are set to the same size as the button with the longest
name.
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To view a demonstration of the previous procedure, click
View Demo
Indentation
Often it is necessary to cluster multiple components under another
component such that it is clear they belong to a group of related functions.
One typical case, for example, is placing several related checkboxes below
a common label. The GUI Builder enables you to accomplish indenting easily
by providing special guidelines suggesting the preferred offset for your
operating system's look and feel.
In this section we'll add a few JRadioButtons below a JLabel that
will allow users to customize the way the application displays
data. Refer to the following illustrations while accomplishing this
or click the View Demo icon following the procedure to view
an interactive demonstration.
To indent JRadioButtons below a JLabel:
- Add a JLabel named Mail Format to the form below the JList.
Make certain the label is left aligned with the JList above.
- In the Palette window, select the JRadioButton component from the
Swing category.
- Move the cursor below the JLabel we just added. When the guidelines
appear indicating that the JRadioButton's left edge is aligned with
that of the JLabel, move the JRadioButton slightly to the right until
secondary indentation guidelines appear. Shift-click to place the first
radio button.
- Move the cursor to the right of the first JRadioButton. Shift-click
to place the second and third JRadioButtons, being careful to respect
the suggested component spacing. Make certain to release the Shift key
prior to positioning the last JRadioButton.
- Double-click each JRadioButton and enter the desired text for each
of their names. Enter
HTML for the left radio button, Plain
Text for the second, and Custom for the third.
Three JRadioButtons are added to the form and indented below the Mail
Format JLabel.
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Now we need to add the three JRadioButtons to a ButtonGroup to enable the
expected toggle behavior in which only one radio button can
be selected at a time. This will, in turn, ensure that our NameFinder application's
contact information will be displayed in the mail format of our choosing.
To add JRadioButtons to a ButtonGroup:
- In the Palette window, select the ButtonGroup component from the
Swing category.
- Click anywhere in the GUI Builder design area to add the ButtonGroup
component to the form. Notice that the ButtonGroup does not appear in the form itself,
however, it is visible in the Inspector's Other Component area.
- Select all three of the JRadioButtons in the form.
- In the Properties window, choose buttonGroup1 from the buttonGroup
property combo box.
Three JRadioButtons are added to the button group.
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To view a demonstration of the previous procedure, click
View Demo
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Making the Final Adjustments
We've managed to rough out our ContactEditor application's GUI, but there are
still a few things remaining to do. In this section we'll take a look at a
couple of other typical layout tasks that the GUI Builder streamlines.
Finishing Up
Now we need to add the buttons that will enable users to
confirm the information they enter for an individual contact and add
it to the contact list or cancel, leaving the database unchanged. In this
step, we'll add the two required buttons and then edit them so that they
appear the same size in our form even though their display text are different
lengths.
To add and edit the display text of buttons:
- If the lower JPanel is extended to the bottom edge of the JFrame form,
drag the bottom edge of the JFrame down. This gives you space between the
edge of the JFrame and the edge of the JPanel for your OK and Cancel buttons.
- In the Palette window, select the JButton component from the
Swing category.
- Move the cursor over the form below the E-mail JPanel. When the
guidelines appear indicating that the JButton's right edge is
aligned with the lower right corner of the JFrame, click to
place the button.
- Add another JButton to the left of the first, making certain to place
it using the suggested spacing along the JFrame's bottom edge.
- Double-click each JButton to select their display text. Enter OK for
the left button and Cancel for right one. Notice that the width
of the buttons changes to accommodate the new names.
- Set the two JButtons to be the same size by selecting both, right-clicking
either, and choosing Same Size > Same Width from the pop-up menu.
The JButton components appear in the form and their corresponding
nodes are displayed in the Inspector window. The JButton components'
code is also added to the form's source file which is visible in the
Editor's Source view. Each of the JButtons are set to the same size as
the button with the longest name.
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The last thing we need to do is delete the placeholder text in
the various components. Note that while removing placeholder text after
roughing out a form can be a helpful technique in avoiding problems with
component alignments and anchoring relationships, most developers typically
remove this text in the process of laying out their forms. As you go through
the form, select and delete the placeholder text for each of the JTextFields.
We'll leave the placeholder items in both the JComboBox and JList for a later
tutorial.
To view a demonstration of the previous procedure, click
View Demo
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Previewing Your GUI
Now that you have successfully built the ContactEditor GUI, you can try your
interface to see the results. You can preview the form as you work by clicking
the Preview Form button ( )
in the GUI Builder's toolbar. The form opens in
its own window, allowing you to test it prior to building and running.

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Deploying GUI Applications
In order for the interfaces you create with the GUI Builder to work
outside of the IDE, an external library containing various layout-related
extensions must be included when deploying your applications. Because the NetBeans
5.0 GUI Builder relies on the Swing Layout Extensions library, it must
also be on your application's classpath at runtime.
You can find a JAR file of the Swing Layout Extensions library in the
following location on your system:
NetBeans_installation_folder/ide6/modules/ext/swing-layout-installed_version.jar
Distributing and Running Standalone GUI Applications
To ensure that your GUI application will automatically use the Swing Layout
Extensions library at runtime, the IDE automatically copies the JAR (and any other JAR
files on the project's classpath) to your the dist/lib folder
whenever you build the project. The IDE also adds each of the JAR files
to the Class-Path element in the application JAR file's manifest.mf
file.
To prepare your GUI application for distribution outside of the IDE:
- Zip the project's dist folder (including the lib folder)
into a ZIP archive.
To run a standalone GUI application from the command line:
- Navigate to the project's dist folder.
- Type the following:
java -jar .jar
Note: If you are using a pre-release version of NetBeans IDE or you
encounter the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/jdesktop/layout/GroupLayout$Group
Ensure that the manifest.mf file references the currently installed version
of the Swing Layout Extensions Library.
For more information about the layout extension library visit the Swing
Layout Extensions project.
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For Further Investigation
You have now completed the IDE's GUI Building tutorial. For more information
on using NetBeans IDE, see:
- Matisse
GUI Builder FAQ. A collection of useful tips and tricks for using
the NetBeans GUI Builder.
- NetBeans Online Help. The documentation included in NetBeans IDE
itself. Press F1 to open the online help.
- Using
NetBeans IDE. The complete guide to developing Java applications
in NetBeans IDE.
- NetBeans Support and Docs. Full
list of articles, FAQs, and mailing lists for NetBeans IDE users.
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