Java Graphical User Interface (GUI)

using Visual Editor in eclipse

CSI 1390 – Java Programming

Instructor: Saeid Nourian

snourian@site.uottawa.ca

University of Ottawa

Fall 2007

Outline

Installing VE Creating Visual Classes GUI Elements Hierarchy of GUI Element Layouts Properties Events Main Method

Download eclipse

Currently VE (VisualEditor) is not compatible with the latest version of eclipse.

To use VE, download older version of eclipse: Eclipse 3.2 (Callisto) http://www.eclipse.org/callisto/

Once download, unzip it and start it by double-clicking on eclipse.exe

Install VE (VisualEditor) plugin

In order to visually create graphical user interface you

need to install the VE plug-in. To install VE:

1) From Help menu of eclipse, click on: Software Updates > Find and Install

Install VE

2) Select “Search for new features to install” and click Next.

Install VE

3) Select “Callisto Discover Site” and click Finish.

Install VE

4) Select a site such as “Canada” when prompted and click Next.

Install VE

5) Select “Visual Editor 1.2.1.v…”

Install VE

6) Click on “Select Required” and click Next.

Install VE

7) Accept the User Agreement and click Next.

8) Click Finish.

Creating VE Projects

VE projects are no different that regular Java projects. Simply build a new Java Project. Later we will add Visual Classes to it.

Adding VE Classes

Click on the drop-down arrow of C* icon and select “Visual Class”

Visual Classes

When the dialog box for making new visual class opens you will have option of several styles: Frame: This is the most common option,

used for creating windows with minimize, maximize and close buttons.

Applet: This is used for creating a visual java class that can be embedded in a Webpage.

Panel: Each Frame is usually consisted of several panels. In order to build your customized panels and then re-use them select this option.

GUI Elements

In order to add GUI elements, click on Palette and select any of the available GUI elements.

Layouts

Java uses Layouts to organize the GUI elements in a Frame or Panel.

In order to disable the automatic Layout organization of GUI elements, you must set the Layout property of the Frame or Panel to “null”. Only then you can freely place GUI element anywhere you want.

Properties

Each GUI element has some properties that can be changes.

As shown in previous example, a Panel has a “layout” property that can be set to null.

A TextBox has other properties such as: Text Foreground [Color] Font PreferedSize etc.

Hierarchy of GUI Elements

Click on “Java Beans” to see the Hierarchy of the current GUI elements in your form.

Some GUI elements such as the Frame and Panel (named jContentPane in this case) are capable of holding many GUI elements as their children.

Events

When a GUI element interacts with human users, it generates “events” to let the program that the user did something.

For example, if we are interested to know if someone has clicked on the OK button, then we must create the “ActionPerformed” event listener.

Events

Events This would generate the following code:

Replace it with:

jButton.addActionListener(new java.awt.event.ActionListener() {public void actionPerformed(java.awt.event.ActionEvent e) {

System.out.println("actionPerformed()"); }

});

jButton.addActionListener(new java.awt.event.ActionListener() {public void actionPerformed(java.awt.event.ActionEvent e) {

jTextField.setText("Hello. OK is now pressed");}

});

main() method

Like other Java applications we did before, we need to have a main() method to start the program.

For GUI application, simple create a new instance of the GUI class and set its visiblity to true:

public static void main(String[] args) {

MyFrame frame = new MyFrame();

frame.setVisible(true);

}

Summary

VE is an easy tool for creating GUI Forms. VE automatically generates Java codes so

that you don’t have to manually make them. Add your own code in the Event parts of the

generated to make the application work.