Jigloo Swing Tutorial
In this simple tutorial you will
small application with an "About" dialog, a menu bar, and the code to
open and close the dialog. You will use the swing's GroupLayout to
arrange the elements on both JFrame and JDialog, and swing Actions to
control the JDialog.
- Arranging elements using GroupLayout - anchoring and
expanding by positioning or resizing or by using the drop-down menu
- Adding Actions to menu items and buttons - and associating
accelerators and mnemonics with actions
- Navigating between visual elements in the tree outline and
- Adding multiple elements
of the same type to a form
- Multi-selecting elements
- "Surround by" action - useful for times when you realise
you really need your table to be in a scroll pane, etc
- Designing multple "root" visual elements in the same form
- in this case a JFrame and a JDialog
- Changing which properties appear under the "Basic" and
"Expert" headings in the "GUI Properties" editor.
First you will need a Java project and (preferably) a package to hold
If you don't know how to do this then hitting Ctrl+N is a quick way to bring up
the "Create" dialog from which you can perform both these steps.
Creating the main JFrame
Create new JFrame
...again, Ctrl+N will show the
"create" dialog, from which you should select "GUI
Choose your editor preferences
Now we've got a Jigloo editor
open, let's change how it looks. Click on the "Open Jigloo preferences
editor" button in the toolbar to the left of the Jigloo editor. The
Eclipse preferences window appears with Jigloo selected. Choose
"Appearance and Behaviour" and then "Tabbed panels". This is useful
when you want to maximize your design area, but "Split-pane" can be
useful if you want to see immediately the connection between code and
Now hit "OK" and close and re-open the Jigloo editor (you need to
do this to change to tabbed panels). If your java class does not
immediately re-open in the Jigloo editor, you can ensure that it uses
Jigloo's Form Editor by right-clicking on the class and choosing "Open
You will probably find it easier
to design a GUI if you can see as much of it as possible, so
double-click on the editor tab and the Jigloo editor will
take over most of Eclipse and arrange itself so you can see an outline
of the elements, the property editor and the form designer.
Set layout to GroupLayout
You can either select the
GroupLayout icon in the "layout" palette, or right-click on the JFrame
and select "Set Layout->GroupLayout"
Add OK and Cancel buttons
If you are using Java 6 then code will be generated for the
javax.swing.GroupLayout which is part of Java 6.
If you are not using Java 6, Jigloo will use the
org.jdesktop.layout.GroupLayout (which is the equivalent of the swing
GroupLayout) and will let you know that it needs to add the
swing-layout-1.0.jar file to your project.
Select the JButton icon from the
"Components" palette and move the cursor down to the bottom-right of
the form until it "clicks" into place.
Make OK and Cancel buttons same
width, and same font
In the dialog that will open (if you have selected that option in the
jigloo preferences) you will be able to set the button's name and text
(and icon if you want). You can also do all this later.
We will make this the "Cancel" button.
Then hold CTRL and SHIFT down and you will be able to add another
button without returning to the component palette.
If you aligned the buttons with the bottom-right of the form
you should see (as in the image above) a faint red arrow connecting the
buttons to the right of
the form and a blue arrow connecting them to the bottom of the form,
indicating that they are anchored to those sides of the form.
also change the anchoring by either re-positioning the buttons next to
of the form, or by using the drop-down alignment menu which you can
access from the
"arrow" button on the top-right of the element. Note all
the menu options, which allow you to change how the element behaves as
the form is resized.
Label the buttons "OK" and "Cancel" - you can double-click on the
button to edit the label, or edit the "text" property.
Multi-select the OK and Cancel
buttons - you can do this using either:
Click on the "Make selected elements the same width" icon in the
- the "rubber band" technique - hold SHIFT down then drag
the mouse over both buttons, then release the mouse, or
- holding CTRL down as you click on the buttons
Then select the OK button - notice that now the "same widths" icon has
changed to "Unlink the selected element's width from all other
elements". This allows you to "unlink" an individual element after it
has been linked.
Now multi-select both buttons again and (just for fun) change
the font to "bold" by clicking on the "font" property in the "GUI
Properties" view and using the dialog that will appear after you click
on the small "..." button.
using the "Components" palette -
add it to the top-left of the form.
Surround by JScrollPane and
stretch it across the form.
Oops - you just remembered you
really meant to add a JScrollPane first, for the table to go inside,
but instead of undoing what you did, you can right-click on the JTabel
and choose "Surround by->JScrollPane".
Add two JTextField (using
quick-repeat) and JButton
Now select the JScrollPane (either in the outline or by clicking on
it's scrollbars, or it's edges - if a scrollpane's child element
occupies all of the area of a scrollpane and there are no scrollbars,
clicking near the edge of the scrollpane will select the scrollpane).
Then drag the side or corner of the JScrollPane so that it stretches
left to the right of the form and is a bit taller. Again, red and blue
indicate that it is connected to both the left and right sides of the
If you open the drop-down menu you will see that "Expands Horizontally"
is checked, and as before you can use that menu to change any of the
listed properties. Note that you will need to uncheck "Expands
horizontally" in order to be able to anchor it left or right.
Just to get a feel for
GroupLayout, add two JTextFields and a JButton, then select them all
and surround by a JPanel and set the JPanel's layout to GroupLayout.
You can resize the panel and move/resize the elements till they look
similar to what is shown below.
Surround JPanel by JTabbedPane
then copy and paste the JPanel into the JTabbedPane
Then edit the JPanel's "Border" property to create a titled border with
This just demonstrates copy and
paste - or you could try cutting and pasting multiple components too
Add JMenuBar with File and Help
Now something a bit more useful
- add a JMenuBar - using the "Menu" palette.
Now double-click on the
"jMenu1" menu and change the text to "File", then add a new "Help"
the menu bar.
Add an "About" action (and menu item) to
the Help menu
Select the "AbstractAction" icon
from the "More components" palette, and then click diretly on the
"Help" menu. Enter "Action" for the action's text property (and call
the action "aboutAction").
If you look at the Outline view you will see that a JMenuItem has been
added to the Help menu and the aboutAction has been associated with it.
The JMenuItem's text will also take on the value of the
AbstractAction's text property.
Test out the form using the "Preview" button
the "About" dialog and linking it to the main frame
Hit the "Preview" button in the
Outline view and click on the "Help" menu - the "About" item should
You can also resize the form and check out how it behaves.
If an element expands horizontally or vertically but you would rather
it not, then make sure the appropriate "Expands" option is not
selected, and then also try the "Reset to default width/height"
options, which should ensure that an element keeps it's default width
Either right-click on a region
outside of the main JFrame and choose "Add container->JDialog" or
choose the JDialog icon from the "Containers" menu and click somewhere
outside of the main JFrame.
Set GroupLayout and add label
and OK button
This will add a totally separate JDialog to the class.
Note the JDialog node on the Outline view. The red border indicates
that this element is the "active" root element, and is being shown in
the form editor.
Try clicking on the "this"
node - the main form will appear. Then click on the "jDialog1" node and
get back to the JDialog.
This is how you can use Jigloo to design multiple "root" elements in
the same Java class.
...using the techniques used
Set horizontalAlignment to
CENTER (and make horizontalAlignment a Basic property)
Select the label, and in the
"GUI Properties" editor,
open the "Expert" node and scroll to "horizontalAlignment". Change this
Add action to dialog's OK
button with code to dispose dialog
Now, if you think you will be using this property failry often then
right-click on it and choose "Set property category for
The horizontalAlignment property (for all elements that have it) will
now appear under the "Basic"
Now, add a "Close" action to the
form - again, choose "AbstractAction" from the "More Components"
palette but this time (for a change) click anywhere on the editor
outside of the JDialog. Set
the text to "OK" and the name to closeAboutAction. Then go to
the Outline view and drag the newly-added action (under the "Extra
components" node) to the dialog's "OK" button.
The action should now
appear twice - once under the "Extra components" node and once under
the dialog's "OK" button. If you wish to disassociate the action with
the OK button, just select the action under the button and hit the
"delete" key. A prompt dialog will ask you if you really want to delete
the action but it will really just remove the action from the button.
If you really want to delete the action, select it first under the
"Extra components" node.
Now, find the close action under the OK button in the Outline view and
double-click on it. The source code will appear and the close action's
code will be highlighted.
Edit the code to add
as shown, so that the dialog will close when the OK button is
Add code to open dialog from the aboutAction
will the dialog appear in the first place? We will add code to the
aboutAction, so double-click on the aboutAction in the Outline view.
Then add the code:
Add an accelerator for the "About" action
We want people to be able to
easily see what this application is about, right? Well, maybe not, but
for the purposes of this demo we will associate an "accelerator" with
the about action.
Select the about action, and in the GUI Properties editor, select the
"accelerator" property - it will be under the "Expert" node, but you
might want to move it to the "Basic" node, as above with the
horizontalAlignment property. Then hold CTRL+SHIFT+A down and you
should should see "ctrl shift A"
appear in the "accelerator" value.
Then release the keys and hit "return" and the code will be
You can also associate a mnemonic with the action in a similar
way - a
mnemonic allows a user to select a menu item by hitting a key (say, A
in this case), but only when the parent menu is visible.
Running the app
You are all done! Hit CTRL+S to save the form. A quick way to run the
main method of the class you
just created is to click the "Run" button in the Outline view.
The main frame should appear in the middle of the screen.
Note: If elements do not appear to be a "comfortable" size when the app
is run, try selecting them in the Jigloo editor and choosing "Reset to
default width/height" from the alignment menu.
Try hitting CTRL+SHIFT+A - the about menu should appear
- woo hoo!
when your curiosity has been thoroughly satisfied you can click the
causing the dialog to disappear.
Note: if you get an "java.lang.UnsupportedClassVersionError: Bad
version number in .class file" message, make sure your compiler
compliance level (set using the properties dialog for your project) is
the same as the version of Java you are running your class with.