AWT New-3.pptx

Java AWT
• Java AWT (Abstract Window Toolkit) is an API to develop Graphical
User Interface (GUI) or windows-based applications in Java.
• The java.awt package provides classes for AWT API such as Text
Field, Label, TextArea, RadioButton, CheckBox, Choice, List etc.

Components
• All the elements like the button, text fields, scroll bars, etc. are called
components.
• In Java AWT, there are classes for each component as shown in above
diagram.
• In order to place every component in a particular position on a screen,
we need to add them to a container.

Container
• The Container is a component in AWT that can contain another
components like buttons, textfields, labels etc.
• The classes that extends Container class are known as container such
as Frame, Dialog and Panel.

Types of containers
• There are four types of containers in Java AWT:
1. Window
2. Panel
3. Frame
4. Dialog

Window
• The window is the container that have no borders and menu bars.
• You must use frame, dialog for creating a window.
• We need to create an object of Window class to create this container.

Panel
• The Panel is the container that doesn't contain title bar, border or menu
bar.
• It can have other components like button, text field etc.
• An object of Panel class creates a container, in which we can add
components.

Frame
• The Frame is the container that contain title bar and border and can
have menu bars.
• It can have other components like button, text field, scrollbar etc.

Useful Methods of Component Class
Method Description
public void add(Component c) Inserts a component on this component.
public void setSize(int width,int height) Sets the size (width and height) of the
component.
public void setLayout(LayoutManager m) Defines the layout manager for the component.
public void setVisible(boolean status) Changes the visibility of the component, by
default false.

Java AWT Button
• The Button class is used to create a button.

Button Class Constructors
Sr. no. Constructor Description
1. Button( ) It constructs a new button
with an empty string i.e. it
has no label.
2. Button (String text) It constructs a new button
with given string as its label.

Button Class Methods
Sr. no. Method Description
1. void setText (String text) It sets the string message
on the button
2. String getText() It fetches the String
message on the button.

import java.awt.*;
class ButtonExample
{
public static void main (String a[])
{
Frame f = new Frame("Button Example");
Button b = new Button("Click Here");
f.setLayout(null);
b.setBounds(50,100,80,30);
f.add(b);
f.setSize(400,400);
f.setVisible(true);
}
}

Java AWT Label
• The Label class is used to create a Label.
• It is used to display a single line of read only text.

Label class Constructors
1. Label() It constructs an empty label.
2. Label(String text) It constructs a label with the
given string.

Label Class Methods
Sr. no. Method name Description
1. void setText(String text) It sets the texts for label
with the specified text.
2. String getText() It gets the text of the label

import java.awt.*;
class LabelExample
{
{
Frame f = new Frame("Button Example");
Label l = new Label("User Name");
l.setBounds(50,100,80,30);
f.setLayout(null);
f.add(l);
f.setSize(400,400);
f.setVisible(true);
}
}

TextField
• TextField allows a user to enter a single line text and edit it.
• It inherits TextComponent class

Constructors of TextField Class
1. TextField() It constructs a new text field
component.
2. TextField(String text) It constructs a new text field
initialized with the given
string text to be displayed.

Methods of TextField Class
1. void setText(String t): It sets the text presented to the specified text.
2. String getText(): It gets the text from the text field.
3. void setEchoChar(char c): It sets the echo character for text field.

import java.awt.*;
class TextFieldExample
{
{
Frame f = new Frame("TextField Example");
TextField t1 = new TextField ();
TextField t2 = new TextField ("User name");
f.setLayout(null);
t1.setBounds(100, 150, 100, 50);
t2.setBounds(100, 250, 100, 50);
f.add(t1);
f.add(t2);
f.setSize(400,400);
f.setVisible(true);
}
}

TextArea
• TextArea allows a user to enter a multiple line text and edit it.
• It inherits TextComponent class

Constructors of TextArea Class
1. TextArea() It constructs a new and
empty text area with no text
in it.
2. TextArea(String text) It constructs a new text area
and displays the specified
text in it.

Methods of TextArea Class
1. void setText(String t): It sets the text presented to the specified text.
2. String getText(): It gets the text from the text area.

import java.awt.*;
class TextAreaExample
{
{
Frame f = new Frame("TextArea Example");
TextArea t1 = new TextArea();
TextArea t2 = new TextArea("User name");
f.setLayout(null);
t1.setBounds(100, 150, 100, 50);
t2.setBounds(100, 250, 100, 50);
f.add(t1);
f.add(t2);
f.setSize(400,400);
f.setVisible(true);
}
}

Java AWT Checkbox
• The Checkbox class is used to create a checkbox.
• It is used to turn an option on (true) or off (false).

Constructors
1. Checkbox() It constructs a checkbox with
no string as the label.
2. Checkbox(String label) It constructs a checkbox with
the given label.
3. Checkbox(String label, boolean state) It constructs a checkbox with
the given label and sets the
given state.

Methods
• void setLabel(String label): It sets the checkbox's label to the string
argument.
• String getLabel(): It gets the label of checkbox.

import java.awt.*;
class CheckboxExample
{
{
Frame f = new Frame("Checkbox Example");
Checkbox c1 = new Checkbox("C++");
Checkbox c2 = new Checkbox("Java", true);
f.setLayout(null);
c1.setBounds(100, 100, 50, 50);
c2.setBounds(100, 180, 50, 50);
f.add(c1);
f.add(c2);
f.setSize(400,400);
f.setVisible(true);
}
}

Java AWT CheckboxGroup
• The object of CheckboxGroup class is used to group together a set
of Checkbox.
• At a time only one check box button is allowed to be in "on" state and
remaining check box button in "off" state.
• It inherits the object class.

Cont…
• Note: CheckboxGroup enables you to create radio buttons in AWT. There is
no special control for creating radio buttons in AWT.

import java.awt.*;
class CheckboxGroupExample
{
{
Frame f = new Frame("CheckboxGroupExample");
CheckboxGroup cbg = new CheckboxGroup();
Checkbox c1 = new Checkbox("C++", cbg, true);
Checkbox c2 = new Checkbox("Java", cbg, false);
f.setLayout(null);
c1.setBounds(100,100, 50,50);
c2.setBounds(100,180, 50,50);
f.add(c1);
f.add(c2);
f.setSize(400,400);
f.setVisible(true);
}
}

Java AWT Choice
• The object of Choice class is used to show popup menu of choices.
• Choice selected by user is shown on the top of a menu.
• Choice class extends Component implements ItemSelectable,
Accessible

Constructor
1. Choice() It constructs a new choice
menu.

Method
• void add(String item): It adds an item to the choice menu.
• String getItem(int index): It gets the item (string) at the given index
position in the choice menu.

import java.awt.*;
class ChoiceExample
{
{
Frame f = new Frame("ChoiceExample");
Choice c = new Choice();
c.add("Item 1");
c.add("Item 2");
c.add("Item 3");
c.add("Item 4");
f.setLayout(null);
c.setBounds(100, 100, 75, 75);
f.add(c);
f.setSize(400,400);
f.setVisible(true);
}

Java AWT List
• The object of List class represents a list of text items.
• With the help of the List class, user can choose either one item or
multiple items.
• List class extends Component class and implements ItemSelectable,
Accessible interface.

Constructors
1. List() It constructs a
new scrolling list.

Method
Sr. no. Method name Description
1. void add(String item) It adds the specified item into the
end of scrolling list.
2. void add(String item, int index) It adds the specified item into list
at the given index position.

import java.awt.*;
class ListExample
{
{
Frame f = new Frame("ListExample");
List l1 = new List();
l1.add("Item 1");
l1.add("Item 2");
l1.add("Item 3");
l1.add("Item 4");
l1.add("Item 5");
f.setLayout(null);
l1.setBounds(100, 100, 75, 75);
f.add(l1);
f.setSize(400,400);
f.setVisible(true);
}
}

Java AWT Scrollbar
• The object of Scrollbar class is used to add horizontal and vertical
scrollbar.
• Scrollbar is a GUI component allows us to see invisible number of
rows and columns.
• Scrollbar class extends Component class and implements Adjustable,

Scrollbar Class Fields
• public static final int HORIZONTAL = 0 - It is a constant to
indicate a horizontal scroll bar.
• public static final int VERTICAL = 1 - It is a constant to indicate a
vertical scroll bar.

Constructors
1 Scrollbar() Constructs a new vertical scroll bar.
2 Scrollbar(int orientation) Constructs a new scroll bar with the
specified orientation.
Where orientation specified whether the scrollbar will be horizontal or vertical.

Method
• void setOrientation(int orientation): It sets the orientation for the scroll
bar.
• int getOrientation(): It returns the orientation of scroll bar.

import java.awt.*;
class ScrollbarExample
{
{
Frame f = new Frame("ScrollbarExample");
Scrollbar s = new Scrollbar();
f.setLayout(null);
s.setBounds(100, 100, 50, 100);
f.add(s);
f.setSize(400,400);
f.setVisible(true);
}
}

MenuBar
• The MenuBar class provides menu bar bound to a frame.
• MenuBar class extends MenuComponent class and implements
MenuContainer, Accessible interface.

Constructor
• MenuBar(): Creates a new menu bar.

Method
• Menu add(Menu m): Adds the specified menu to the menu bar.
• Menu getMenu(int i): Gets the specified menu.

Menu
• A menu has a pull-down list of menu items from which the user can
select one at a time.
• When many options in multiple categories exist for selection by the
user, menus are the best choice since they take less space on the frame.
• Menu class extends MenuItem class and implements MenuContainer,

Menu Hierarchy
• Menu creation involves many classes, like MenuBar, MenuItem
and Menu and one is added to the other.

Cont…
• A MenuBar is capable of holding the menus and a Menu can hold
menu items.
• Menus are placed on a menu bar.

Procedure for Creating Menus
• Create menu bar
• Add menu bar to the frame
• Create menus
• Add menus to menu bar
• Create menu items
• Add menu items to menus
• Event handling

import java.awt.*;
class MenuExample
{
{
Frame f = new Frame("MenuExample");
f.setLayout(null);
MenuBar mb=new MenuBar();
Menu menu=new Menu("Menu");
MenuItem i1=new MenuItem("Item 1");
Menu submenu=new Menu("Sub Menu");
MenuItem i2=new MenuItem("Item 2");
submenu.add(i2);
menu.add(i1);
menu.add(submenu);
mb.add(menu);
f.setMenuBar(mb);
f.setSize(400,400);
f.setVisible(true);
}
}

AWT New-3.pptx

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AWT New-3.pptx