abstract window toolkit

1. UNIT-5

2.  Advantages of GUI over CUI
 The AWT class hierarchy- Component, Frame
 User interface components:
Labels, button, scrollbars
 Text components, check box, check box groups, choices
 Lists panels – ScrollPane, MenuBar, graphics
 Layout manager – layout manager types
boarder, grid, flow and card layouts.
Applications:
Developing calculator, Developing feedback
form,Developing biodata.

3. Advantages of GUI over CUI
Presents a user-friendly mechanism for interacting with an
application.
Built from GUI components.
It need more resources
Speed is less compare to the CUI
In a Command Line Interface, the commands are entered from
the keyboard. It is not user-friendly.
Difficult to remember commands.
It need less resources
Speed is more compare to the GUI

4. Most modern programs use a GUI.
 Graphical: Not just text or characters but windows, menus,
buttons, ..
 User: Person using the program
 Interface: Way to interact with the program
Graphical Elements include:
Window List
Choice Label
Menu Scrollbar
Button TextComponent etc.,

5.  AWT (AbstractWindowingToolkit) is an API to develop GUI
or window-based application in java.
 AWT contains large number of classes and methods that
allows you to create and manage windows GUI application
 AWT components are platform-dependent i.e. components
are displayed according to the view of operating system.
AWT is heavyweight i.e. its components uses the resources of
system.
 The java.awt package provides classes for AWT api such as
TextField, Label,TextArea, RadioButton, CheckBox, Choice,
List etc.

6. button menus title bar menu bar combo box
scroll
bars
Internet Explorer Window with GUI components

7. AWT HIERARCHY

8. AWT class hierarchy
MenuBar
Component
Container
Window Panel
Frame
Label
Button
TextComponent
TextField
TextArea
Choice
CheckBox
CheckBoxGroup
Scrollbar
MenuComponent
List
MenuItem
Menu
Dialog
Canvas
ScrollPane
Applet

9. Component: (java.awt)
Component class is at the top of AWT hierarchy.
Component is an abstract class that encapsulates all of
the attributes of a visual component.
It is a super class of all user interface classes.
A component is something that can be displayed on a
two-dimensional screen and with which the user can
interact.
Attributes of a component include a size, a location,
foreground and background colors, whether or not visible
etc.,

10. Methods defined in class Component are:
 setLocation(int, int), getLocation() ---To set and get component
location
 setSize(int, int), getSize() ---To set and get component
size
 setVisible() ---To show or hide the
component
 setForeground(Color), getForeground() ---To set and get
foreground colors
 setBackground(Color), getBackground() ---To set and get
background colors

11. Container
 The Container is a component inAWT 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.
This is a type of component that can nest other
components within it.
Ex:- Window, Frame, and panel are examples of
containers.
 Container is a subclass of component
class. Conatiner class keeps track of components that
are added to another component.

12. Methods defined in a class Container are:
 setLayout(LayoutManager) ---To set layout
manager for display.
 add( Component ) ---To add component to
the display.
 remove( Component ) ---To remove
component from display.

13. Frames
 Frame is a window that is not contained inside another window.
Frame is the basis to contain other user interface components in Java
graphical applications.
 Frame’s constructors:
Frame( )
Frame(String title)
 After a frame window has been created, it will not be visible until you call
setVisible( true).

14. Frame Location
 By default, a frame is displayed at the upper- left corner
of the screen.
 To display a frame at a specified location, use
setLocation(x,y) method.

15. Frame Method-1
import java.awt.*;
public class MyFrame
{
public static void main( String args[] )
{
Label l=new Label(“userId”);
Button b1=new Button(“ok”);
Textfield t1=newTextField();
Frame f = new Frame(“MyFrame");
f.add(l);
f.add(b1);
f.add(t1);
f.setSize(300,200);
f.setVisible(true);
}
}

16. Method-II
import java.awt.*;
public class MyFrame extends Frame
{
MyFrame()
{
super(“title of Frame”);
Label l=new Label(“userId”);
add(l);
setSize(300,200);
setVisible(true);
}
}
class ExFrame
{
public static void main( String args[] )
{
new MyFrame();
}
}

17. Panel: (java.awt)
 The Panel class is a concrete subclass of Container class.
 A panel is a window that does not contain a title bar, or border.
 It provides space in which an application can attach any other component,
including other panels.
 It is the superclass for Applet.
 Other components can be added to a Panel object by its add() method.
 The default layout manager for a panel is the FlowLayout layout manager.

18. Panel
This class creates panels,which are containers used to organize
and control the layout of other components such as labels, buttons,
text fields, and so on.
 A Panel looks like a window that does not contain a title bar, menu
bar, or border.
It is recommended that you place the user interface components in
panels and place the panels in a frame.
You can also place panels in a panel.
FlowLayout is the default layout for panel.
Panel()
Panel(LayoutManager layout)

19. import java.awt.*;
public class Ex013Panel extends Frame
{
public Ex013Panel()
{
super("Panel test");
setLayout(null);
Panel pan1 = new Panel();
pan1.setSize(200,100);
pan1.setBackground(Color.red);
pan1.setLocation(50,50);
add( pan1 );
Button button1 = new Button(“ok");
Button button2 = new Button(“cancel");
pan1.add( button1 );
pan1.add( button2 );
......................
Panel

20. Window: (java.awt)
The window is the container that have no borders and menu bars.
 The Window class creates a top-level window.
 A top-level window is not contained within any other object; it sits
directly on the desktop.
 Generally, we won’t create Window objects directly. Instead, we use
a subclass of Window called Frame.

21. Frame: (java.awt)
 It is a type of Window with a title bar, menu bar , borders, and
resizing corners. It can have other components like button, textfield
etc.
Methods defined in a Frame class are:
 setTitle(String), getTitle() ---To set or get title
 setMenuBar(MenuBar) ---To set menu bar for
window
 Frame is a sub class of Window and have resizing canvas. It is a container
that contain several different components like button, title bar, textfield,
label etc. In Java, most of theAWT applications are created
using Framewindow. Frame class has two different constructors,
 Frame() throws HeadlessException
 Frame(String title) throws HeadlessException

22. Layout Manager:
 A manager is used to position and place components in a
Container

23. USER INTERFACE COMPONENTS
 To simplify user interaction and make data entry easier, you
can use java controls.
 Controls are components, such as
buttons
labels
text boxes, etc
that can be added to containers like
 frames,
 panels and
 applets.

25. AWT Packages
AWT is huge! It consists of 12 packages, only 2 packages –
 java.awt and
 java.awt.event - are commonly-used.
The java.awt package contains the core AWT graphics classes:
 GUI Component classes (such as Button, TextField, and Label),
 GUI Container classes (such
as Frame, Panel, Dialog and ScrollPane),
 Layout managers (such
as FlowLayout, BorderLayout and GridLayout),
 Custom graphics classes (such as Graphics, Color and Font).

26. Controls in Java
Controls Functions
Textbox Accepts single line alphanumeric entry.
TextArea
Accepts multiple line alphanumeric
entry.
Push button Triggers a sequence of actions.
Label Displays Text.
Check box
Accepts data that has a yes/no value.
More than one checkbox can be
selected.
Radio button
Similar to check box except that it allows
the user to select a single option from a
group.
Combo box
Displays a drop-down list for single item
selection. It allows new value to be
entered.
Similar to combo box except that it

27. Classes Involved
Controls Class
Textbox TextField
TextArea TextArea
Push button Button
Check box CheckBox
Radio button CheckboxGroup with CheckBox
Combo box Choice
List box List

28. AWT GUI Component: java.awt.Button
 A java.awt.Button is a GUI component that triggers a
certain programmed action upon clicking.
To create a button use, one of the following constructors:
 Button() creates a button with no text label.
 Button(String) creates a button with the given string as
label.
Constructors
 public Button(String buttonLabel); // Construct a Button
with the given label
 public Button(); // Construct a Button with empty label

29. Now let ustart with the simplest UI Component the Button
import java.awt.*;
class First extends Frame{
First(){
Button b=new Button("click me");
b.setBounds(30,100,80,30);// setting button position
add(b);//adding button into frame
setSize(300,300);//frame size 300 width and 300 height
setLayout(null);//no layout manager
setVisible(true);//now frame will be visible, by default not visible
}
public static void main(String args[]){
First f=new First();
}}

31.  The setBounds(int xaxis, int yaxis, int width, int height)
method is used in the above example that sets the position of
the awt button.
 We can use the setLabel( ) method to change the label of the
button and the getLabel( ) method to retrieve the caption

32. Label Component
 Labels are created via the Label class. Labels are often used to
identify the purpose of other components on a given interface; they
cannot be edited directly by the user. Using a label is much easier.
 Labels can be laid out according to the layout manager.
 To create a Label, use one of the following constructors:
Label( ) - creates a label with its string aligned to the left..
 Label(String) - creates a label initialized with the given string, and
aligned left.
 Label(String, int) - creates a label with specified text and alignment
indicated by the int argument: Label.Right, Label.Left and
Label.Center.

33. Label
Label()
Label( String text )
setText(String text)
getText()
We can use label’s getText( ) method to indicate the
current label’s text and setText( ) method to change
the label’s text
Labels are passive controls that do not support
any interaction with the user.
User-Interface Components

34. import java.awt.*;
public classTestawt {
Testawt()
{
Frame fm=new Frame(); //Creating a frame.
Label lb = new Label("welcome to java graphics"); //Creating a
label
fm.add(lb); //adding label to the frame.
fm.setSize(300, 300); //setting frame size.
fm.setVisible(true); //set frame visibilty true.
}
public static void main(String args[]) {
Testawt ta = newTestawt();
} }

36. Text Components
 To accept textual data from a user,AWT provided two
classes, TextField andTextArea.
 TheTextField handles a single line of text and does not have
scrollbars, whereas theTextArea class handles multiple lines
of text. Both the classes are derived from theTextComponent
class

37.  To create a text field, use one of the following constructors:
 TextField() creates an emptyTextField with no specified width.
 TextField(int) creates an empty text field with enough width to
display the specified number of characters (this has been
depreciated in Java2).
 TextField(String) creates a text field initialized with the given
string.
 TextField(String, int) creates a text field with specified text and
specified width.

38. Methods of TextField-
setText(String) –
getText() –
setEchoChar(char) – The text Field allows you to specify
an echo character that helps you accept a password without
displaying what the user has keyed in.
Example:
TextField tf = newTextField(30);
tf.setEchoCharacter('*');
setEditable(bolean) –

39. import java.awt.*;
public class ExTextField extends Frame
{
public ExTextField()
{
super("TextField test");
setLayout(new FlowLayout());
TextField text1 = new TextField(“hello",30);
add( text1 );
...........................
TextField

40. TextArea
 TheTextArea is an editable text field that can handle more than one
line of input.Text areas have horizontal and vertical scrollbars to
scroll through the text.Adding a text area to a container is similar to
adding a text field.
To create a text area use one of the following constructors:
TextArea() creates an empty text area with unspecified width and
height.
 TextArea(int, int) creates an empty text area with indicated number
of lines and specified width in characters.
 TextArea(String) creates a text area initialized with the given string.
 TextField(String, int, int) creates a text area containing the indicated
text and specified number of lines and width in the characters.

41. import java.awt.*;
public class ExTextArea extends Frame
{
public ExTextArea()
{
super("TextArea test");
setLayout(new FlowLayout());
TextArea text1 = new TextArea(5,30);
add( text1 );
..........................
TextArea

42. Checkbox
Checkbox()
Checkbox(String text)
Checkbox(String text , boolean state)
Checkbox(String text , CheckboxGroup group , boolean state)
getLabel() – String
setLabel() – void
getState() – boolean
setState() – boolean

43. import java.awt.*;
public class ExCheckbox extends Frame
{
public ExCheckbox()
{
super("Checkbox test");
setLayout(new FlowLayout());
Checkbox check1 = new Checkbox(“java");
Checkbox check2 = new Checkbox(“dbms");
Checkbox check3 = new Checkbox(“se");
add( check1 );
add( check2 );
add( check3 );
setSize(300,200);
setVisible(true);
}
.............................
Checkbox

44. Checkbox Groups, Choices, and Lists
 Three types of interface components are used to select one
item from a set of possibilities.
 First is a group of connected check boxes with the property that
only one can be selected at a time.( also called radio buttons ).
 Second is choice. A choice displays only one selection, but when
the user clicks in the selection area, a pop-up menu appears that
allows the choice to be changed to a different selection.
 A third is a List. A List is similar to a choice, but several items out of
the range can be displayed at a time and we can select multiple
items.
 Use checkbox Group when the number of alternatives is
small.

45. CheckboxGroup()
Checkbox(String text , CheckboxGroup group , boolean state)
Checkbox getSelectedCheckbox( )
CheckboxGroup / Radio buttons

46. CheckboxGroup/Radio Buttons
import java.awt.*;
public class ExRadioButton extends Frame
{
public ExRadioButton()
{
super("Radio Button test");
setLayout(new FlowLayout());
CheckboxGroup cbg = new
CheckboxGroup();
Checkbox check1 = new Checkbox(“java",cbg,true);
Checkbox check2 = new Checkbox(“dbms",cbg,false);
Checkbox check3 = new Checkbox(“se",cbg,false);
add( check1 );
add( check2 );
add( check3 );
.....................

47. Choice
Choice()
add(String) – void ,Items are added to the list in the order
in which calls to add( ) occur.
getItemCount() – int
getItem(int) – String
remove(int) –void
getSelectedItem() – String
select(int index) - void
select(String name) --void

48. import java.awt.*;
public class ExChoice extends Frame
{
public ExChoice()
{
super("Choice Button test");
setLayout(new FlowLayout());
Choice choice1 = new Choice();
choice1.add(“java");
choice1.add(“dbms");
choice1.add(“se");
add( choice1 );
setSize(300,200);
setVisible(true);
....................
Choice

49. List
List()
List(int rows)
List(int rows, boolean multipleMode)
add(String) – adds item to the end of the list
add(String,int index) – adds item at index
getItemCount() –
getItem(int) –
remove(int) –
getSelectedItem() –
getSelectedItems()

50. import java.awt.*;
public class ExList extends Frame
{
public ExList()
{
super("List test");
setLayout(new FlowLayout());
List List1 = new List(3,false);
List1.add(“java");
List1.add(“dbms");
List1.add(“se");
List1.add(“ppl");
List1.add(“co");
add( List1 );
...................
List

51.  To create a menu bar, first create an instance of MenuBar.
Consturctor - MenuBar( )
 This class only defines the default constructor.
 a menu bar contains one or more Menu objects.
 Next, create instances of Menu ( menus)
Constructors
 Menu( )
 Menu(String menuName)
 Individual menu items are of type MenuItem.
Constructors
 MenuItem( )
 MenuItem(String itemName)
 MenuItem(String itemName, MenuShortcut keyAccel)
MenuBars , Menus, MenuItems

52. Contd..
 You can disable or enable a menu item by using the setEnabled( )
method of menuItem.
 You can determine an item’s status by calling isEnabled( ) method of
menuItem.
 You can change the name of a menu item by calling setLabel( )
method of menuItem.

53. import java.awt.*;
public class ExMenubar extends Frame
{
public Exmenubar()
{
super(“Menubar test");
MenuBar mbar = new MenuBar();
setMenuBar(mbar);
Menu file = new Menu("File");
MenuItem item1, item2, item3, item4, item5;
file.add(item1 = new MenuItem("New..."));
file.add(item2 = new MenuItem("Open..."));
file.add(item3 = new MenuItem("Close"));
file.add(item4 = new MenuItem("-"));
file.add(item5 = new MenuItem("Quit..."));
mbar.add(file);
..........................

54. Scrollbar
Scroll bars are used to select continuous values between a specified
minimum and maximum.
The maximum and minimum values can be specified .
The line increment can be specified( the amount scroll bar will move
when it is touched in the line ends).
The page increment can be specified ( the amount scroll bar will move
when it is touched in the background area between the thumb and the
end).

55.  Scrollbar()
 Scrollbar(int style)
 Scrollbar(int style,int initialValue, int thumbSize, int min, int max)
 Constants
 Scrollbar.VERTICAL
 Scrollbar.HORIZONTAL
 getValue()
 Scrollbar(Scrollbar.HORIZONTAL,0, 60, 0, 300);
 getValue()
 setValue(int newValue);
 Minimum : default 0.
 Maximum : default 100
 Default line increment is 1 unit
 Default page increment is 10 unit.

56. import java.awt.*;
public class ExScrollbar extends Frame
{
public ExScrollbar()
{
super("Scrollbar test");
setLayout(new FlowLayout());
Scrollbar scroll1 = new Scrollbar(Scrollbar.HORIZON
Scrollbar scroll2 =
new Scrollbar(Scrollbar.HORIZONTAL,100, 60, 0, 30
add( scroll1 );
add( scroll2 );
...........................
Scrollbar

57. ScrollPane
It is similar to a panel.
It can hold only one Component.
If size of the component held is larger than the size of the
ScrollPane, scroll bars will be automatically generated.
It does not have a LayoutManager
ScrollPane()

58. import java.awt.*;
public class ExScrollPane extends Frame
{
public Ex014ScrollPane()
{
super("ScrollPan test");
setLayout(null);
ScrollPane sPane1 = new
ScrollPane();
sPane1.setSize(200,100);
sPane1.setBackground(Color.red);
sPane1.setLocation(50,50);
Panel pan1 = new Panel();
TextArea text1 = new
TextArea(300,500);
pan1.add( text1 );
sPane1.add( pan1 );
add( sPane1 );
......................
ScrollPane

59. Layout
 Layout means the arrangement of components within
the container. In other way we can say that placing the
components at a particular position within the
container.
Layout Manager:
 The layout manager automatically positions all the
components within the container.
Java provide us with various layout manager to
position the controls.

60.  The properties like size,shape and arrangement varies
from one layout manager to other layout manager.
 The layout manager is associated with every Container
object.
 Every container has a default Layout Manager:
Panel FlowLayout
Window (Frame) BorderLayout
To set layout manager:
myContainer.setLayout( new
LayoutManger() );

61.  Layout Managers
Flow Layout
Grid Layout
Border Layout
Card Layout

62. Flow Layout
 The Flow Layout manager arranges the components left-to-right,
top-to-bottom in the order they were inserted into the container.
 The FlowLayout is the default layout.It layouts the components in a
directional flow.
 When the container is not wide enough to display all the
components, the remaining components are placed in the next
row, etc.
 By default each row is centered.
 The line alignment can be:
FlowLayout.LEFT
FlowLayout.CENTER
FlowLayout.RIGHT

63. Flow Layout Example
English French Greek
Japanese German
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Arabic Chinese Russian

64. Flow Layout Constructors
 FlowLayout()
//A centered alignment and a default 5-unit horizontal and vertical gap.
 FlowLayout(align)
align – alignment used by the manager. A default 5-unit horizontal and
vertical gap.
 FlowLayout(align, hgap, vgap)
//align – alignment used by the manager
//hgap – horizontal gaps between components
//vgap – vertical gaps between components

65. import java.awt.*;
public class MyFrame
{
public static void main( String args[] )
{
Button b1=new Button("1");
Button b2=new Button("2");
Button b3=new Button("3");
Button b4=new Button("4");
Button b5=new Button("5");
Frame f = new Frame("MyFrame");

66. f.add(b1);
f.add(b2);
f.add(b3);
f.add(b4);
f.add(b5);
f.setLayout(new FlowLayout(FlowLayout.RIGHT));
f.setSize(300,200);
f.setVisible(true);
}
}

67.  The BorderLayout is used to arrange the components in five regions:
north, south, east, west and center. Each region (area) may contain
one component only. It is the default layout of frame or window.The
BorderLayout provides five constants for each region:
 public static final int NORTH
 public static final int SOUTH
 public static final int EAST
 public static final intWEST
 public static final int CENTER
BorderLayout

68. Border Layout
 The Border Layout manager arranges components into five regions: North,
South, East, West, and Center.
 Components in the North and South are set to their natural heights and
horizontally stretched to fill the entire width of the container.
 Components in the East and West are set to their natural widths and
stretched vertically to fill the entire width of the container.
 The Center component fills the space left in the center of the container.
 If one or more of the components, except the Center component, are missing
then the rest of the existing components are stretched to fill the remaining
space in the container.
 The positional constraints are:
BorderLayout.NORTH BorderLayout.SOUTH
BorderLayout.EAST BorderLayout.WEST
BorderLayout.CENTER

69.  Components in the North and South are set to their natural
heights and horizontally stretched to fill the entire width of the
container.
 Components in the East andWest are set to their natural widths
and stretched vertically to fill the entire height of the container.
 The Center component fills the space left in the center of the
container.
 If one or more of the components, except the Center
component, are missing then the rest of the existing
components are stretched to fill the remaining space in
the container.

70. BorderLayout Manager
North
South
Center East
West
To set BorderLayout:
add( new Button(“ok”), BorderLayout.NORTH);

71. Border Layout Constructors
 BorderLayout()
//No vertical or horizontal gaps.
 BorderLayout(hgap, vgap)
//hgap – horizontal gaps between components
//vgap – vertical gaps between components

72. import java.awt.*;
class BorderLayout{
BorderLayout()
{
Frame f=new Frame();
Button b1=new Button("1");
Button b2=new Button("2");
Button b3=new Button("3");
Button b4=new Button("4");
Button b5=new Button("5");
f.add(b1,BorderLayout.NORTH);
f.add(b2,BorderLayout.SOUTH);
f.add(b3,BorderLayout.EAST);

73. f.add(b4,BorderLayout.WEST);
f.add(b5,BorderLayout.CENTER);
f.setSize(300,300);
f.setVisible(true);
}
public static void main(String args[])
{
new BorderLayout();
}
}

74. GridLayout
 The GridLayout is used to arrange the components in
rectangular grid. One component is displayed in each
rectangle.

75. Grid Layout
 Container is divided into a grid where components are placed in
rows and columns.
 Every component has the same width and height.
 Example

76. Grid Layout Constructors
 GridLayout()
//A single row and no vertical or horizontal gaps.
 GridLayout(r, c)
//r – number of rows in the layout
//c – number of columns in the layout
//No vertical or horizontal gaps.
 GridLayout(r, c, hgap, vgap)
//r – number of rows in the layout
//c – number of columns in the layout
//hgap – horizontal gaps between components
//vgap – vertical gaps between components

77. import java.awt.*;
class GridLayout{
GridLayout()
{
Frame f=new Frame();
Button b1=new Button("1");
Button b2=new Button("2");
Button b3=new Button("3");
Button b4=new Button("4");
Button b5=new Button("5");
f.add(b1);
f.add(b2);
f.add(b3);
f.add(b4);
f.add(b5);

78. f.setLayout(GridLayout(3,3));
f.setSize(300,300);
f.setVisible(true);
}
public static void main(String args[])
{
new GridLayout();
}
}

79. CARD LAYOUT CLASS
 The CardLayout class manages the components in such a
manner that only one component is visible at a time. It treats
each component as a card that is why it is known as
CardLayout.
• You can see only one card at a time.
• By default, the first card is visible.
• We can put any card on top using the methods
next(), previous(), first(), last(), and show().

80. Constructors of CardLayout class:
 CardLayout(): creates a card layout with zero horizontal
and vertical gap.
 CardLayout(int hgap, int vgap): creates a card layout
with the given horizontal and vertical gap.

81. Methods:
public void first(Container parent);
public void next(Container parent);
public void previous(Container parent);
public void last(Container parent);
public void show(Container parent, String name);
First Card
add(component, name)
New Card