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Swing components are built aspart of JFC(JAVA FOUNDATIONCLASSES).

Swing components are lightweight components as they are

written in java. Swing components are built on

top of AWT.

Swing components are consistent

across all platforms they look andwork alike in all platforms.

Swing components are madeavailable in javax.swing package.

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swing components

ButtonsCommonbuttons

Radio

buttonsCheckbuttons

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Swing components

Comboboxes

Lists

Menus

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Swing components

Spinners

Sliders

Textfields

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Console vs. GUI applications

What is the differencebetween a GUI and aconsole app?

From the programmersperspective?

A console app enables interactionthrough a specified flow of I/Os. A GUI

app makes it much more flexible. Theuser is allowed to perform combinationsof actions. The programmer must havetaken all possible behaviors in mind.

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Swing classes

Components you use to builda GUI app, are instances ofclasses contained in thejavax.swing package:

JButton

JTextField

JRadioButton

JCheckBox

JComboBox

JLabeletc

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Building GUIs essentials

A GUI consists of a number ofcomponents contained in somepane.

To appear onscreen, every GUIcomponent must be part of acontainment hierarchy. Acontainment hierarchy is a tree ofcomponents that has a top-levelcontainer as its root.

For Java apps this top-levelcontainer will typically be a

JFrame. Components will then be pinned

on the top-level containerscontent pane.

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Building GUIs essentials

JFrame

object Containerobject

JButton object

JLabel object

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Building GUIs essentials

Putting this in code:

import javax.swing.*;

public class MyApp extends JFrame{

private JButton b1;

private JLabel l1;

Public MyApp(){

super(SwingApplication");

Container myCont = getContentPane();

b1=new JButton(Im a Swing button!);l1= new JLabel(Number of button clicks: + num);

myCont.add(b1);

myCont.add(l1);

}

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and again

JList: JList()

JList(Vector v)

Example:

String[] data = {"one", "two",

"three", "four"};

JList dataList = new JList(data);

dataList.add(five);

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and again

JRadioButton: JRadioButton(String s, Icon i,

boolean state)

Example:

JRadioButton rb1= newJRadioButton(one);

JRadioButton rb2= new

JRadioButton(two);

ButtonGroup bg= new ButtonGroup();

bg.add(rb1);

bg.add(rb2);

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Layout Managers

You use layout managersto design your GUIs.

There are severalmanagers like: FlowLayout

BorderLayout

GridLayout

CardLayout GridBagLayout

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FlowLayout

Default layout Components laid out

from the top-left corner,

from left to right and topto bottom like a text.

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BorderLayout

Places components in up to five areas:top, bottom, left, right, and center. Allextra space is placed in the center area

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GridLayout

Simply makes a bunch of componentsequal in size and displays them in the

requested number of rows and columns

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CardLayout

lets you implementan area that containsdifferent components

at different times. ACardLayout is oftencontrolled by acombo box, with the

state of the combobox determiningwhich panel (group ofcomponents) theCardLayout displays

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GridBagLayout

is a sophisticated, flexible layout manager.It aligns components by placing themwithin a grid of cells, allowing some

components to span more than one cell.

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Layout Managers

Putting it into code: Setting the manager:Container myCont = getContentPane();

myCont.setLayout(new FlowLayout());

Adding Components:myCont.add(aComponent, BorderLayout.WEST);

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