Swing and AWT in java

Agenda of today Presentation
 Introduction to GUI
 Introduction to AWT
 Introduction to Swing
 Difference b/w Swing and Awt
 Why we'll recomend to use "SWING"
 Introduction to Component,Container,Panels,window,Frame
 Implemention of JFrame and Adding component
 We can add component directly on frame
 Working with NETBEANS to make GUI

What is GUI( graphical user interface)?
 A GUI (pronounced “GOO-ee”) gives an application a
distinctive “look and feel.”
 A graphical user interface is a visual interface to a
program. GUIs are built from GUI components
(buttons,menus, labels etc). A GUI component is an
object with which the user interacts via the mouse or
keyboard.
 Together, the appearance and how user interacts with
the program are known as the program "look and feel".
 The classes that are used t o create GUI components
are part of the java.awt or javax.swin g package.
Both these packages provide rich set of user
interface components.

GUI vs Non-GUI
 The classes present in the awt and swing packages
can be classified into two broad categories. GUI
classes & Non-GUI Support classes.
 The GUI classes as the name indicates are visible
and user can interact with them. Examples of these
are JButton, JFrame & JRadioButton etc
 The Non-GUI support classes provide services and
perform necessary functions for GUI classes. They
do not produce any visual output. Examples of
these classes are Layout managers & Event
handling(will discussed latter by another group)

What is AWT?
 AWT stands for Abstract Windowing Toolkit contains original
but not pure GUI components that came with the first release
of JDK.
 These components are tied directly to the local platform‘s
(Windows, Linux, MAC etc)graphical user interface
capabilities. Thus results in a java program executing on
different java platforms(windows, Linux, Solaris etc) has a
different appearance and sometimes even different user
interaction on each platform.
 AWT components are often called Heavy Weight
Components (HWC) as they rely on the local platform‘s
windowing system.
 AWT component it creates a corresponding process on the
operating system.
 Inshort component of AWT are OS depended

About Swing
 These are the newest GUI components. Swing components
are written, manipulated and displayed completely in java,
therefore also called pure java components. The swing
component s allow the programmer to specify a
uniform look and feel across all platforms.
 javax.swing package is use to import
 not dedpend on operating system
 99% have lightweight components
 A rich set of class whic contain
 Jpanels,Jbutton,JTextarea,...............and so
 Name start from J of swing class

Superclasses of Swing’s Lightweight GUI Components
The Fig. shows an inheritance hierarchy of classes from which
lightweight Swing components inherit their common attributes and behaviors.

Swing vs AWT
 OS independent
 Light weight
 base on Write once use
anywhere
 feel and look
 rich set of object
 OS dedpendent
 Heavy weight
 Not consistent as
compared to Swing
 change behaviour due to
os
 less as compared to
swing

Why we prefer to Swing
On the Basis of last slide that we disscused so we
can say that Swing is better becoz
not depend on OS
light weight
new version of JDK
write once use anywhere base

Component
 At the top of the AWT hierarchy is
theComponentclass.Componentis an abstract
class that
encapsulates all of the attributes of a visual
component. All user interface elements that are
displayed on the screen and that interact with the
user are subclasses ofComponent. It defines over
a hundred public methods that are responsible
for managing events, such as mouse and
keyboard input, positioning and sizing the
window, and repainting.

12
components examples
 JButton button = new JButton("Click me!");
 JLabel label = new JLabel("This is a JLabel");
 JTextField textField1 = new JTextField("This is the initial text");
 JTextField textField2 = new JTextField("Initial text", columns);
 JTextArea textArea1 = new JTextArea("Initial text");
 JTextArea textArea2 = new JTextArea(rows, columns);
 JTextArea textArea3 = new JTextArea("Initial text", rows, columns);
 JCheckBox checkbox = new JCheckBox("Label for checkbox");
 JRadioButton radioButton1 = new JRadioButton("Label for button");
 ButtonGroup group = new ButtonGroup();
group.add(radioButton1); group.add(radioButton2); etc.
 This is just a sampling of the available constructors; see the javax.swing API
for all the rest

Container
 TheContainerclass is a subclass ofComponent. It has
additional methods that allow other Componentobjects
to be nested within it. OtherContainerobjects can be
stored inside of a Container(since they are themselves
instances ofComponent). This makes for a multileveled
containment system. A container is responsible for
laying out (that is, positioning)
Two important methods the container class has add and setLayout.
Container are classified into two broad categories that are
Top Level containers andGeneral Purpose Containers Top
level containers can contain (add) other containers
as well as basic components (buttons, labels etc) while
general purpose containers are typically used to collect
basiccomponents and are added to top level containers.

Panel
 ThePanelclass is a concrete subclass ofContainer. It
doesn’t add any new methods; it simply implements
Container. A Panel may be thought of as a recursively
nestable, concrete screen component.
 When screen output is directed to an Frame/applet,it is
drawn on the surface of a Panel object.
 Panelis a window that does not contain a title bar, menu
bar, or border

Window
 TheWindowclass creates a top-level
window. A top-level window is not
contained within any other object; it sits
directly on the desktop. Generally, you
won’t createWindowobjects directly.
Instead, you will use a subclass of Window
called Frame, described next.

Frame
 Frame encapsulates what is commonly thought of as a
“window.” It is a subclass of Window and has a title bar,
menu bar, borders, and resizing corners.
 It contain Jlabel,textarea,button etc
 in previous hierarchy we observe that JFrame is a
frame is a window. So, it can be interpreted as
JFrame is a window.
 A simple frame

17
How to build a GUI
 Create a window in which to display things—usually a JFrame
(for an application), or a JApplet
 Use the setLayout(LayoutManager manager) method to
specify a layout manager
 Create some Components, such as buttons, panels, etc.
 Add your components to your display area, according to your
chosen layout manager
 Write some Listeners and attach them to your Components
 Interacting with a Component causes an Event to occur
 A Listener gets a message when an interesting event occurs, and executes
some code to deal with it
 Display your window

Step 1 and 2: Code for JFrame
import pakages
public class MyFirstFrame{
public static void main(String[] args) {
JFrame myFrame=new
JFrame("my frame");
myFrame.setSize(500, 500);//size
of the frame widht and height
myFrame.setVisible(true);
//this v.impt visibilty
myFrame.setDefaultCloseOperation
(JFrame.EXIT_ON_CLOSE);
}
}

step#3: code for getting content area
JFrame myFrame=new JFrame("my frame");
myFrame.setSize(333, 333);
myFrame.setDefaultCloseOperation(JFrame.
EXIT_ON_CLOSE);
 Container c =
myFrame.getContentPane(
);
 So now we are able to add component in
that area of frame
This content/panel area

step#4: code for Applaying layout
JFrame myFrame=new JFrame("title of frame");
myFrame.setSize(333, 333);
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container c = myFrame.getContent Pane();
c.setLayout( new FlowLayout());
 There are different method of layout but we will use one
for the code and introduce all in the next slide
 The purpose of layout that how they component are
apear in frame

Step 5: create & add components
JTextField t f = new
JTextField(10) ;
JButton b1 = new
JButton( "My Button");
JButton b2= new JButton("My
2nd Button");
Button b=new Button("Awt
button");
//Adding commponent to
container
c.add(tf);
c.add(b1);

Step 6: set size of frame and make it visible
myFrame.setDefaultCloseOperat
ion(JFrame.EXIT_ON_CLOS
E);
myFrame.setSize(200,150);
output:

23
Add a layout manager
 The most important layout managers are:
 BorderLayout
 Provides five areas into which you can put components
 This is the default layout manager for both JFrame and JApplet
 FlowLayout
 Components are added left to right, top to bottom
 GridLayout
 Components are put in a rectangular grid
 All areas are the same size and shape
 BoxLayout
 Creates a horizontal row or a vertical stack
 This can be a little weird to use

mport java.awt.BorderLayout;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
/**
* @author Adil M
*/
public class JavaApplication9 {
///code for border layout
// TODO code application logic here
JFrame a=new JFrame("my frame");
a.setLayout(new BorderLayout());
JButton bt=new JButton("North");
a.add(bt,BorderLayout.NORTH);
JButton bt1=new JButton("west");
a.add(bt1,BorderLayout.WEST);
JButton bt2=new JButton("center");
a.add(bt2,BorderLayout.CENTER);
JButton bt3=new JButton("East");
a.add(bt3,BorderLayout.EAST);
JButton bt4=new JButton("south");
a.add(bt4,BorderLayout.SOUTH);
a.setSize(500,500);
a.setVisible(true);
a.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

26
FlowLayout
 public class FlowLayoutExample extends JFrame {
public void init () {
setLayout(new FlowLayout ());
add(new JButton("One"));
add(new JButton("Two"));
add(new JButton("Three"));
add(new JButton("Four"));
add(new JButton("Five"));
add(new JButton("Six"));
}
}

27
GridLayout
 public class GridLayoutExample extends JApplet {
public void init() {
setLayout(new GridLayout(2, 4));
add(new JButton("One"));
add(new JButton("Two"));
add(new JButton("Three"));
add(new JButton("Four"));
add(new JButton("Five"));
}
}

28
BoxLayout
 public class BoxLayoutExample extends JApplet {
public void init () {
Box box = new Box(BoxLayout.Y_AXIS);
add(box);
box.add(new JButton("One"));
box.add(new JButton("Two"));
box.add(new JButton("Three"));
box.add(new JButton("Four"));
box.add(new JButton("Five"));
box.add(new JButton("Six"));
}
}

29
Nested layouts
 A JPanel is both a JContainer and a Component
 Because it’s a container, you can put other components into it
 Because it’s a component, you can put it into other containers
 All but the very simplest GUIs are built by creating
several JPanels, arranging them, and putting
components (possibly other JPanels) into them
 A good approach is to draw (on paper) the arrangement
you want, then finding an arrangement of JPanels and
their layout managers that accomplishes this

We can Add commponents on frame
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class JavaApplication9 {
JFrame a=new JFrame("my frame");
//SET LAYOUT FOR FRAME most imp
a.setLayout(new
FlowLayout());
JButton bt=new JButton("Button 1");
a.add(bt);
JButton bt1=new JButton("Button31");
a.add(bt1);
a.setSize(500,500);
a.setVisible(true);
a.setDefaultCloseOperation(JFrame.EXIT_ON_C
LOSE);

31
How to build a GUI(Step by Step)
Code for Simple GUI
// File GUITest.java
//Step 1: import packages
import java.awt .*;
import javax.swing.*;
public class GUITest {
JFrame myFrame ;
JTextField tf;
JButto n b;
//method used for set ting layout of GUI
public void initGUI ( ) {
//St ep 2: setup the top level cont ainer
myFrame = new JFrame();

continue......
//St ep 3: Get the component area of top-level container
Container c = myFrame.getContent Pane();
//Step 4: Apply layo ut s
c.setLayout( new FlowLayout( ) );
//Step 5: create & add components
JTextField t f = new JTextField(10) ;
JButton b1 = new JButton( "My Button");
c.add(tf);
c.add(b1);
//Step 6: set size of frame and make it visible
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.setSize(200,150);
} //end initGUI method

continue......
public GUITest ( ) { // default constructor
initGUI ();
}
public static void main (Strin g args[ ]) {
GUITest gui = new GUITest();
}
}

Code for simple layout of calculator
To make the calculator GUI shown
above, take JFrame (top level
container) and set it s layout to
border. Than take JPanel (general
purpose container) and set its layout
to Grid with 4 rows and 4 columns.

calculator cont......
public class NewClass {
JFrame fCalc=new JFrame("Swing Presentation by Adil");
JButton b1, b2, b3, b4, b5, b6, b7, b8, b9, b0;
JButton bPlus,bMinus,bMul,bPoint,bEqual,bCl ,ear;
JPanel pButtons;
JTextField tfAn, swer;
JLabel lMyCalc;
public static void main(String[] args)
{
NewClass v= new NewClass();
}
public void method(){
try
{
bPlus=new JButton("");
b1=new JButton("1");

bMinus = new JButton("-");
bMul = new JButton("*");
bPoint = new JButton(".");
bEqual = new JButton("=");
bCl = new JButton("C");
tfAn = new JTextField(10);
tfAn.setSize(20, 20);
lMyCalc = new JLabel("My Clacualator");
//creating panel object and setting its layout
pButtons = new JPanel (new GridLayout(4,4));
//adding components (buttons) to panel
pButtons.add(b1);
pButtons.add(b2);
pButtons.add(b3);
pButtons.add(bCl);

pButtons.add(b4);
pButtons.add(b5);
pButtons.add(b6);
pButtons.add(bMul);
pButtons.add(b7);
pButtons.add(b8);
pButtons.add(b9);
pButtons.add(bMinus);
pButtons.add(b0);
pButtons.add(bPoint);
pButtons.add(bPlus);
pButtons.add(bEqual);
// getting componenet area of JFrame
Container con=new Container();
con=fCalc.getContentPane();
con.setLayout(new BorderLayout()) ;
//adding components to container
con.add(tfAn, BorderLayout.NORTH);
con.add(lMyCalc, BorderLayout.SOUTH);
con.add(pButtons, BorderLayout.CENTER);
fCalc.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
fCalc.setSize(300, 300);
fCalc.setVisible(true);
}

catch(Exception ex)
{
JOptionPane.showMessageDialog(null,ex.getStackTrace());
}
}
public NewClass ()
{ // default const ructor
method();
}
}

40
Getting values
 Some user actions normally cause the program to do
something: clicking a button, or selecting from a menu
 Some user actions set values to be used later: entering
text, setting a checkbox or a radio button
 You can listen for events from these, but it’s not usually a
good idea
 Instead, read their values when you need them
 String myText = myJTextField.getText();
 String myText = myJTextArea.getText();
 boolean checked = myJCheckBox.isSelected();
 boolean selected1 = myJRadioButton1.isSelected();

41
Enabling and disabling components
 It is poor style to remove components you don’t want
the user to be able to use
 “Where did it go? It was here a minute ago!”
 It’s better to enable and disable controls
 Disabled controls appear “grayed out”
 The user may wonder why?, but it’s still less confusing
 anyComponent.setEnabled(enabled);
 Parameter should be true to enable, false to disable

42
Dialogs
 A dialog (small accessory window) can be modal or
nonmodal
 When your code opens a modal dialog, it waits for a result
from the dialog before continuing
 When your code opens a nonmodal dialog, it does so in a
separate thread, and your code just keeps going
 Sun supplies a few simple (but useful) modal dialogs for
your use
 You can create your own dialogs (with JDialog), but
they are nonmodal by default

43
Message dialogs
 JOptionPane.showMessageDialog(parentJFrame,
"This is a JOptionPane "message" dialog.");
 Notice that showMessageDialog is a static method of
JOptionPane
 The “parentJFrame” is typically your main GUI
window (but it’s OK to use null if you don’t have a
main GUI window)

44
Confirm dialogs
 int yesNo =
JOptionPane.showConfirmDialog(parentJFrame,
"Is this what you wanted to see?");
 if (yesNo == JOptionPane.YES_OPTION) { ... }

45
Input dialogs
 String userName =
JOptionPane.showInputDialog(parentJFrame,
"What is your name?")

46
Option dialogs
 Object[] options =
new String[] {"English", "Chinese", "French", "German" };
int option =
JOptionPane.showOptionDialog(parentJFrame,
"Choose an option:",
"Option Dialog",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE,
null,
options,
options[0]); // use as default
 Fourth argument could be JOptionPane.YES_NO_CANCEL_OPTION
 Fifth argument specifies which icon to use in the dialog; it could be one of
ERROR_MESSAGE, INFORMATION_MESSAGE, WARNING_MESSAGE, or
PLAIN_MESSAGE
 Sixth argument (null above) can specify a custom icon

47
Load file dialogs
 JFileChooser chooser = new JFileChooser();
chooser.setDialogTitle("Load which file?");
 int result = chooser.showOpenDialog(enclosingJFrame);
if (result == JFileChooser.APPROVE_OPTION) {
File file = chooser.getSelectedFile();
// use file
}
 You could also test for
CANCEL_OPTION or
ERROR_OPTION
 You will get back a File
object; to use it, you must
know how to do file I/O

48
Save file dialogs
 JFileChooser chooser = new JFileChooser();
chooser.setDialogTitle(“Save file as?");
 int result = chooser.showSaveDialog(enclosingJFrame);
if (result == JFileChooser.APPROVE_OPTION) {
File file = chooser.getSelectedFile();
// use file
}
 You could also test for
CANCEL_OPTION or
ERROR_OPTION
 You will get back a File
object; to use it, you must
know how to do file I/O

Review
 Introduction to GUI
 Introduction to AWT
 Introduction to Swing
 Difference b/w Swing and Awt
 Why we'll recomend to use "SWING"
 Introduction to Component,Container,Panels,window,Frame
 Implemention of JFrame and Adding component
 Working with NETBEANS to make GUI

Swing and AWT in java

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