Java AWT Controls and methods, Listener classes

Assistant Professor
Assistant Professor
Department of Computer Science
Department of Computer Science
Kristu Jayanti College
Kristu Jayanti College
Bangalore
Bangalore
AWT CONTROLS
Presented by
November 29, 2024
November 29, 2024
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Java Applet
Java Applet

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Java AWT
Java AWT
 Java AWT
Java AWT (Abstract Window Toolkit) is an API to
(Abstract Window Toolkit) is an API to
develop GUI or window-based applications in java.
develop GUI or window-based applications in java.
 Java AWT components are platform-dependent
Java AWT components are platform-dependent
 The java.awt
The java.awt package provides classes for AWT api
package provides classes for AWT api
 such as TextField, Label, TextArea, RadioButton,
such as TextField, Label, TextArea, RadioButton,
CheckBox, Choice, List etc.
CheckBox, Choice, List etc.
November 29, 2024
November 29, 2024 Java Applet
Java Applet

Windows Fundamental
Windows Fundamental
Container
Container
 The Container is a component in AWT
The Container is a component in AWT
 That can contain another components
That can contain another components
like buttons, textfields, labels etc.
like buttons, textfields, labels etc.
 The classes that extends Container class
The classes that extends Container class
are known as container such as Frame,
are known as container such as Frame,
Dialog and Panel.
Dialog and Panel.
November 29, 2024
Java Applet
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…
…Windows Fundamental
Windows Fundamental
Window
Window
 The window is the container
The window is the container
 Have no borders and menu bars.
Have no borders and menu bars.
 Frame, dialog or another window for creating a
Frame, dialog or another window for creating a
window.
window.
 Panel
Panel
 The Panel is the container
The Panel is the container
 that doesn't contain title bar and menu bars.
that doesn't contain title bar and menu bars.
 It can have other components like button,
It can have other components like button,
textfield etc.
textfield etc.
November 29, 2024
Java Applet
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…
…Windows Fundamental
Windows Fundamental
Frame
Frame
 The Frame is the container
The Frame is the container
 That contain title bar and can have
That contain title bar and can have
menu bars.
menu bars.
 It can have other components like
It can have other components like
button, textfield etc.
button, textfield etc.
November 29, 2024
Java Applet
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Methods of Component class
public void add(Component c)
public void add(Component c)
inserts a component on this component.
inserts a component on this component.
Ex: add(
Ex: add(b
b);
);
public void setSize(int width,int height)
public void setSize(int width,int height)
sets the size (width and height) of the
sets the size (width and height) of the
component.
component.
Ex: setSize(
Ex: setSize(300,300
300,300)
)
November 29, 2024
Java Applet
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…
…Methods of Component class
public void setLayout(LayoutManager m)
public void setLayout(LayoutManager m)
defines the layout manager for the
defines the layout manager for the
component.
component.
Ex: setLayout(
Ex: setLayout(null
null);
);
public void setVisible(boolean status)
public void setVisible(boolean status)
changes the visibility of the component,
changes the visibility of the component,
by default false.
by default false.
Ex: setVisible(
Ex: setVisible(true
true);
);
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Java Applet
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Sample Code
Sample Code
import java.awt.*;
import java.awt.*;
class First1 extends Frame{
class First1 extends Frame{
First1(){
First1(){
Button b=new Button("click me");
b.setBounds(30,100,80,30);// setting button position
b.setBounds(30,100,80,30);// setting button position
add(b);//adding button into frame
add(b);//adding button into frame
setSize(300,300);//frame size 300 width and 300 height
setSize(300,300);//frame size 300 width and 300 height
setLayout(null);//no layout manager
setLayout(null);//no layout manager
setVisible(true);//now frame will be visible, by default not visible
setVisible(true);//now frame will be visible, by default not visible
}
}
public static void main(String args[]){
public static void main(String args[]){
First1 f=new First1();
First1 f=new First1();
}}
}}
November 29, 2024
Java Applet
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Event and Listener
Event and Listener
 Changing the state
Changing the state of an object is
of an object is
known as an event.
known as an event.
 For example,
For example, click on button
click on button,
, dragging
dragging
mouse
mouse etc.
etc.
 The java.awt.event package provides
The java.awt.event package provides
many
many event classes
event classes and
and Listener
Listener
interfaces
interfaces for event handling.
for event handling.
November 29, 2024
Java Applet
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Event classes and Listener interfaces
Event classes and Listener interfaces
Event Classes Listener Interfaces
ActionEvent ActionListener
MouseEvent MouseListener and
MouseMotionListener
MouseWheelEvent MouseWheelListener
KeyEvent KeyListener
ItemEvent ItemListener
TextEvent TextListener
AdjustmentEvent AdjustmentListener
WindowEvent WindowListener
ComponentEvent ComponentListener
ContainerEvent ContainerListener
FocusEvent FocusListener
November 29, 2024
Java Applet
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Registration Methods
 Button
Button
 public void addActionListener(ActionListener
public void addActionListener(ActionListener
a){}
a){}
 MenuItem
MenuItem
a){}
a){}
 TextField
TextField
a){}
a){}
 public void addTextListener(TextListener a){}
public void addTextListener(TextListener a){}
November 29, 2024
Java Applet
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…
…Registration Methods
 TextArea
TextArea
 public void addTextListener(TextListener a){}
public void addTextListener(TextListener a){}
 Checkbox
Checkbox
 public void addItemListener(ItemListener a){}
public void addItemListener(ItemListener a){}
 Choice
Choice
 List
List
 public void addActionListener(ActionListener a)
public void addActionListener(ActionListener a)
{}
{}
November 29, 2024
Java Applet
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Sample Code
Sample Code
import java.awt.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.*;
class AEvent extends Frame implements ActionListener{
class AEvent extends Frame implements ActionListener{
TextField tf;
TextField tf;
AEvent(){
AEvent(){
//create components
//create components
tf=new TextField();
tf=new TextField();
tf.setBounds(60,50,170,20);
tf.setBounds(60,50,170,20);
b.setBounds(100,120,80,30);
b.setBounds(100,120,80,30);
//register listener
//register listener
b.addActionListener(this);//passing current instance
b.addActionListener(this);//passing current instance
//add components and set size, layout and visibility
//add components and set size, layout and visibility
add(b);add(tf);
add(b);add(tf);
setSize(300,300);
setSize(300,300);
setLayout(null);
setLayout(null);
setVisible(true); }
setVisible(true); }
public void actionPerformed(ActionEvent e){
public void actionPerformed(ActionEvent e){
tf.setText("Welcome to III Maths"); }
tf.setText("Welcome to III Maths"); }
November 29, 2024
Java Applet
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Button and Label
Button and Label
 The application result in some action
The application result in some action
when the button is pushed.
when the button is pushed.
Button b=new Button("Click Here");
Button b=new Button("Click Here");
 It is used to display a single line of read
It is used to display a single line of read
only text.
only text.
 The text can be changed by an
The text can be changed by an
application but a user cannot edit
application but a user cannot edit
Label l1=new Label("First Label.");
Label l1=new Label("First Label.");
November 29, 2024
Java Applet
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TextField and TextArea
TextField and TextArea
 TextField class is a text component that
TextField class is a text component that
allows the editing of a single line text
allows the editing of a single line text
TextField t1=new TextField(“III Maths");
TextField t1=new TextField(“III Maths");
 TextArea class is a multi line region that
TextArea class is a multi line region that
displays text.
displays text.
 Editing of multiple line text.
Editing of multiple line text.
TextArea area=new TextArea("Welcome to III
TextArea area=new TextArea("Welcome to III
Maths");
Maths");
November 29, 2024
Java Applet
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Checkbox and Choice
Checkbox and Choice
 The Checkbox class is used to create a
The Checkbox class is used to create a
checkbox.
checkbox.
 It is used to turn an option on (true) or off
It is used to turn an option on (true) or off
(false).
(false).
Checkbox checkbox1 = new Checkbox("C++");
Checkbox checkbox1 = new Checkbox("C++");
 Choice class is used to show popup menu
Choice class is used to show popup menu
of choices
of choices
Choice c=new Choice();
Choice c=new Choice();
November 29, 2024
Java Applet
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MenuItem and Menu
MenuItem and Menu
 The object of MenuItem class adds a
The object of MenuItem class adds a
simple labeled menu item on menu
simple labeled menu item on menu
 The object of Menu class is a pull down
The object of Menu class is a pull down
menu
menu
MenuBar mb=new MenuBar();
MenuBar mb=new MenuBar();
Menu menu=new Menu("Menu");
Menu menu=new Menu("Menu");
November 29, 2024
Java Applet
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PopupMenu
PopupMenu
 PopupMenu can be dynamically popped up
PopupMenu can be dynamically popped up
 Specific position within a component.
Specific position within a component.
 It inherits the Menu class.
It inherits the Menu class.
final
final PopupMenu popupmenu =
PopupMenu popupmenu = new
new Popup
Popup
Menu("Edit");
Menu("Edit");
MenuItem cut = new MenuItem("Cut");
MenuItem cut = new MenuItem("Cut");
November 29, 2024
Java Applet
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Panel
Panel
 It provides space in which an
It provides space in which an
application can attach any other
application can attach any other
component
component
 It doesn't have title bar.
It doesn't have title bar.
Panel panel=new Panel();
Panel panel=new Panel();
November 29, 2024
Java Applet
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Dialog
Dialog
 title used to take some form of input
title used to take some form of input
from the user
from the user
 it doesn't have maximize and minimize
it doesn't have maximize and minimize
buttons.
buttons.
Dialog d= new Dialog(f , "Dialog Example", true);
Dialog d= new Dialog(f , "Dialog Example", true);
November 29, 2024
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ActionListener
ActionListener
 whenever you click on the button or
whenever you click on the button or
menu item
menu item
 It has only one method:
It has only one method:
actionPerformed()
actionPerformed()
public abstract void actionPerformed
public abstract void actionPerformed
(ActionEvent e);
(ActionEvent e);
November 29, 2024
Java Applet
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MouseListener
MouseListener
 whenever you change the state of mouse
whenever you change the state of mouse
 It has five methods.
It has five methods.
 public
public abstract
abstract void
void mouse
mouseClicked
Clicked(MouseEvent e);
(MouseEvent e);
 public
public abstract
abstract void
void mouse
mouseEntered
Entered(MouseEvent e);
(MouseEvent e);
 public
public abstract
abstract void
void mouse
mouseExited
Exited(MouseEvent e);
(MouseEvent e);
 public
public abstract
abstract void
void mouse
mousePressed
Pressed(MouseEvent e);
(MouseEvent e);
 public
public abstract
abstract void
void mouse
mouseReleased
Released(MouseEvent e);
(MouseEvent e);
November 29, 2024
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KeyListener
KeyListener
 whenever you change the state of key.
whenever you change the state of key.
 It is notified against KeyEvent
It is notified against KeyEvent
 public
public abstract
abstract void
void keyPressed
keyPressed(KeyEv
(KeyEv
ent e);
ent e);
 public
public abstract
abstract void
void keyReleased
keyReleased(KeyE
(KeyE
vent e);
vent e);
 public
public abstract
abstract void
void keyTyped
keyTyped(KeyEven
(KeyEven
t e);
t e);
November 29, 2024
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November 29, 2024
November 29, 2024
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Java Applet
Java Applet
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Java AWT Controls and methods, Listener classes

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