javax.swing package

What is swing?

Swing is a part of JFC (java Foundation Classes) that is used to create GUI application. It is built on the top of AWT and entirely written in java.

Disadvantage of AWT

AWT had some serious shortcomings, To understand Swing, it helps to understand its predecessor, AWT. As its name suggests, AWT is an abstraction. However, people generally expect their application to have a consistent look and feel but AWT is full dependent to platforms, so if the code developed under Windows, then run it on an X Window System or a Macintosh and get more or less the native look and feel on each platform.

Advantage of Swing over AWT

There are many advantages of Swing over AWT, They are as follows

• Swing components are platform independent
• It is lightWeight.
• It supports pluggable look and feel.
• It has more powerful components like tables, lists, scroll panes, color chooser, tabbed pane etc.
• It follows MVC (Model View Controller) architecture.

Frequently used methods present in Component class

• Container getParent()
• String getName()
• void setName(String name)

Get or assign the String name of this component . Naming a component is useful for debugging. The name is returned by toString().

• void setVisible(boolean visible)

Make the component visible or invisible within its container. If you change the component's visibility, the container's layout manager automatically lays out its visible components.

• Color getForeground()
• void setForeground(Color c)
• void setBackground(Color c)
• Color getBackground()

Get and set the foreground and background colors for this component. The foreground color of any component is the default color used for drawing. For example, it is the color used for text in a text field as well as the default drawing color for the Graphics object passed to the component's paint() and paintComponent() methods. The background color is used to fill the component's area when it is cleared by the default implementation of update().

• Dimension getSize()
• void setSize(int width, int height)

Get the current size of the component. Note that a layout manager may change the size of a component even after you've set its size yourself.

• Dimension getPreferredSize()
• void setPreferredSize(Dimension preferredSize)

use these methods to examine or set the preferred size of a component. Layout managers attempts to set components to their preferred sizes. If you change a component's preferred size, you must call the method revalidate() on the component to get it laid out again.

• Cursor getCursor()
• void setCursor(Cursor cursor)

Get or set the type of cursor used when the mouse is over this

Container

Containers are integral part of SWING GUI components. A container provides a space where a component can be located.

Following is the list of commonly used containers while designed GUI using SWING.

1. JFrame

A JFrame is a window that has a border, title, and supports button components which are used to close or iconify the window. GUI applications uses JFrame.

Example of JFrame by Inheritance

import javax.swing.*;

class Test extends JFrame

{

Test() {

setSize(300,300);

setLocation(100,100);

setTitle("hungry4java");

setVisible(true);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); /*to close the JFrame when exit button at top right corner is clicked.*/

}

public static void main(String[] args) {

new Test();

}

}

JWindow

Like Window, it uses BorderLayout by default. JWindow is the component that can be displayed without being added or attached to another Container. After creating a JWindow, you can call the setVisible() method to display it.

Example of JWindow

public class TopLevelWindows

{

public static void main(String[] args)

{

JFrame frame = new JFrame("hungry4java.blogspot.com");

frame.setSize(300,300);

frame.setLocation(100,100);

frame.setVisible(true);

JWindow window = new JWindow();

window.setSize(300,300);

window.setLocation(500,100);

window.setVisible(true);

}

}

JDialog

A JDialog is a window which is used to "talk" to the application. A dialog is used to input data, modify data, change the application settings etc. Dialogs are important means of communication between a user and a computer program.

Example of JDialog

import javax.swing.*;

class Test

{

public static void main(String[] args)

{

JFrame frame = new JFrame("hungry4java.blogspot.com");

frame.setSize(300,300);

frame.setLocation(100,100);

frame.setVisible(true);

JWindow window = new JWindow();

window.setSize(300,300);

window.setLocation(500,100);

window.setVisible(true);

JDialog dialog = new JDialog();

dialog.setSize(300,300);

dialog.setLocation(900,100);

dialog.setVisible(true);

}

}

JPanel

A JPanel object is a lightweight (simple) container to hold graphical components, JPanel holds other "normal" graphical components (such as Labels. buttons, etc) and other JPanels.

Example of JPanel

import javax.swing.*;

class JPanelDemo
{
public static void main(String[] args)
{
JFrame frame = new JFrame("hungry4java.blogspot.com");
frame.setSize(300,300);
frame.setLocation(100,100);
frame.setVisible(true);

JPanel panel = new JPanel();
frame.add(panel);

JButton button = new JButton("click!");
panel.add(button);
}

}

JApplet

JApplet is a container which contains any swing components, that can runs in web browser.

• To compile write "C:\Users\Abhishek\Desktop>FileName.java"
• And to run your JApplet write "C:\Users\Abhishek\Desktop>appletViewer FileName.java

Example of JApplet

import java.awt.*;

import javax.swing.*;

public class Test extends JApplet

{

public void paint(Graphics g)

{

g.drawString("Hello..welcome to hungry4java.blogspot.com",150,150);

}

}

/*

<applet code=Test.class width=300 height=300

</applet>

*/