Chapter 01 Introduction to AWT
Chapter 01
Introduction the Abstract Window Toolkit (AWT)
Contents:
1.1 Working with Windows and AWT
AWT classes
Windows Fundamentals
Working with frame windows
Creating a frame window in applet
Creating windowed program
Display information within a window
1.2 Working with graphics
Working with color
Setting the paint mode
Working with Fonts
Managing text output using Font Metrics
Exploring text & graphics
1.3 Using AWT Controls, Layout Managers and Menus
Control Fundamentals
Labels
Using Buttons
Applying Check Boxes
Checkbox Group
Choice Controls
Using Lists
Managing scroll Bars
Using a Text Field
Using a Text Area
Understanding Layout Managers
Menu Bars and Menu
Dialog Boxes
File Dialog
1.4 Handling events by Extending AWT Components
Exploring the Controls, Menus, and Layout Managers
Advanced Java Programming -1-
, Chapter 01 Introduction to AWT
Abstract Window Toolkit:
The AWT contains numerous classes and methods that allow us to create
and manage windows. Although the main purpose of the AWT is to support
applet windows, it can also be used to create stand-alone windows that run in a
GUI environment, such as Windows.
AWT Classes
The AWT classes are contained in the java.awt package. It is one of
Java‘s largest packages. Fortunately, because it is logically organized in a top-
down, hierarchical fashion, it is easier to understand and use than you might at
first believe.
AWTEvent Encapsulates AWT events.
AWTEventMulticaster Dispatches events to multiple listeners.
BorderLayout The border layout manager. Border layouts use five
components: North, South, East, West, and Center.
Button Creates a push button control.
Canvas A blank, semantics-free window.
CardLayout The card layout manager. Card layouts emulate index
cards. Only the one on top is showing.
Checkbox Creates a check box control.
CheckboxGroup Creates a group of check box controls.
CheckboxMenuItem Creates an on/off menu item.
Choice Creates a pop-up list.
Color Manages colors in a portable, platform-independent
fashion.
Component An abstract super-class for various AWT components.
Container A subclass of Component that can hold other
components.
Cursor Encapsulates a bitmapped cursor.
Dialog Creates a dialog window.
Dimension Specifies the dimensions of an object. The width is
stored in width, and the height is stored in height.
Event Encapsulates events.
EventQueue Queues events.
FileDialog Creates a window from which a file can be selected.
FlowLayout The flow layout manager. Flow layout positions
components left to right, top to bottom.
Font Encapsulates a type font.
FontMetrics Encapsulates various information related to a font. This
information helps you display text in a window.
Frame Creates a standard window that has a title bar, resize
corners, and a menu bar.
Advanced Java Programming -2-
, Chapter 01 Introduction to AWT
Graphics Encapsulates the graphics context. This context is used
by the various output methods to display output in a
window.
GraphicsDevice Describes a graphics device such as a screen or printer.
GraphicsEnvironment Describes the collection of available Font and
GraphicsDevice objects.
GridBagConstraints Defines various constraints relating to the
GridBagLayout class.
GridBagLayout The grid bag layout manager. Grid bag layout displays
components subject to the constraints specified by
GridBagConstraints.
GridLayout The grid layout manager. Grid layout displays
components in a two-dimensional grid.
Image Encapsulates graphical images.
Insets Encapsulates the borders of a container.
Label Creates a label that displays a string.
List Creates a list from which the user can choose. Similar
to the standard Windows list box.
MediaTracker Manages media objects.
Menu Creates a pull-down menu.
MenuBar Creates a menu bar.
MenuComponent An abstract class implemented by various menu classes.
MenuItem Creates a menu item.
MenuShortcut Encapsulates a keyboard shortcut for a menu item.
Panel The simplest concrete subclass of Container.
Point Encapsulates a Cartesian coordinate pair, stored in x
and y.
Polygon Encapsulates a polygon.
PopupMenu Encapsulates a pop-up menu.
PrintJob An abstract class that represents a print job.
Rectangle Encapsulates a rectangle.
Robot Supports automated testing of AWT- based applications.
Scrollbar Creates a scroll bar control.
ScrollPane A container that provides horizontal and/or vertical
scroll bars for another component.
SystemColor Contains the colors of GUI widgets such as windows,
scroll bars, text, and others.
TextArea Creates a multiline edit control.
TextComponent A superclass for TextArea and TextField.
TextField Creates a single-line edit control.
Toolkit Abstract class implemented by the AWT.
Window Creates a window with no frame, no menu bar,
Advanced Java Programming -3-
, Chapter 01 Introduction to AWT
Window Fundamentals
The AWT defines windows according to a class hierarchy that adds
functionality and specificity with each level. The two most common windows are
those derived from Panel, which is used by applets, and those derived from
Frame, which creates a standard window. Much of the functionality of these
windows is derived from their parent classes. Thus, a description of the class
hierarchies relating to these two classes is fundamental to their understanding.
Figure below shows the class hierarchy for Panel and Frame.
Component
Container
MenuContainer Window Panel
Interface
Frame Applet
Component
At the top of the AWT hierarchy is the Component class. Component is 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 of Component. 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.
A Component object is responsible for remembering the current foreground and
background colors and the currently selected text font.
Container
The Container class is a subclass of Component. It has additional
methods that allow other Component objects to be nested within it. Other
Container objects can be stored inside of a Container (since they are
themselves instances of Component). This makes for a multileveled
containment system. A container is responsible for laying out (that is,
Advanced Java Programming -4-
Chapter 01
Introduction the Abstract Window Toolkit (AWT)
Contents:
1.1 Working with Windows and AWT
AWT classes
Windows Fundamentals
Working with frame windows
Creating a frame window in applet
Creating windowed program
Display information within a window
1.2 Working with graphics
Working with color
Setting the paint mode
Working with Fonts
Managing text output using Font Metrics
Exploring text & graphics
1.3 Using AWT Controls, Layout Managers and Menus
Control Fundamentals
Labels
Using Buttons
Applying Check Boxes
Checkbox Group
Choice Controls
Using Lists
Managing scroll Bars
Using a Text Field
Using a Text Area
Understanding Layout Managers
Menu Bars and Menu
Dialog Boxes
File Dialog
1.4 Handling events by Extending AWT Components
Exploring the Controls, Menus, and Layout Managers
Advanced Java Programming -1-
, Chapter 01 Introduction to AWT
Abstract Window Toolkit:
The AWT contains numerous classes and methods that allow us to create
and manage windows. Although the main purpose of the AWT is to support
applet windows, it can also be used to create stand-alone windows that run in a
GUI environment, such as Windows.
AWT Classes
The AWT classes are contained in the java.awt package. It is one of
Java‘s largest packages. Fortunately, because it is logically organized in a top-
down, hierarchical fashion, it is easier to understand and use than you might at
first believe.
AWTEvent Encapsulates AWT events.
AWTEventMulticaster Dispatches events to multiple listeners.
BorderLayout The border layout manager. Border layouts use five
components: North, South, East, West, and Center.
Button Creates a push button control.
Canvas A blank, semantics-free window.
CardLayout The card layout manager. Card layouts emulate index
cards. Only the one on top is showing.
Checkbox Creates a check box control.
CheckboxGroup Creates a group of check box controls.
CheckboxMenuItem Creates an on/off menu item.
Choice Creates a pop-up list.
Color Manages colors in a portable, platform-independent
fashion.
Component An abstract super-class for various AWT components.
Container A subclass of Component that can hold other
components.
Cursor Encapsulates a bitmapped cursor.
Dialog Creates a dialog window.
Dimension Specifies the dimensions of an object. The width is
stored in width, and the height is stored in height.
Event Encapsulates events.
EventQueue Queues events.
FileDialog Creates a window from which a file can be selected.
FlowLayout The flow layout manager. Flow layout positions
components left to right, top to bottom.
Font Encapsulates a type font.
FontMetrics Encapsulates various information related to a font. This
information helps you display text in a window.
Frame Creates a standard window that has a title bar, resize
corners, and a menu bar.
Advanced Java Programming -2-
, Chapter 01 Introduction to AWT
Graphics Encapsulates the graphics context. This context is used
by the various output methods to display output in a
window.
GraphicsDevice Describes a graphics device such as a screen or printer.
GraphicsEnvironment Describes the collection of available Font and
GraphicsDevice objects.
GridBagConstraints Defines various constraints relating to the
GridBagLayout class.
GridBagLayout The grid bag layout manager. Grid bag layout displays
components subject to the constraints specified by
GridBagConstraints.
GridLayout The grid layout manager. Grid layout displays
components in a two-dimensional grid.
Image Encapsulates graphical images.
Insets Encapsulates the borders of a container.
Label Creates a label that displays a string.
List Creates a list from which the user can choose. Similar
to the standard Windows list box.
MediaTracker Manages media objects.
Menu Creates a pull-down menu.
MenuBar Creates a menu bar.
MenuComponent An abstract class implemented by various menu classes.
MenuItem Creates a menu item.
MenuShortcut Encapsulates a keyboard shortcut for a menu item.
Panel The simplest concrete subclass of Container.
Point Encapsulates a Cartesian coordinate pair, stored in x
and y.
Polygon Encapsulates a polygon.
PopupMenu Encapsulates a pop-up menu.
PrintJob An abstract class that represents a print job.
Rectangle Encapsulates a rectangle.
Robot Supports automated testing of AWT- based applications.
Scrollbar Creates a scroll bar control.
ScrollPane A container that provides horizontal and/or vertical
scroll bars for another component.
SystemColor Contains the colors of GUI widgets such as windows,
scroll bars, text, and others.
TextArea Creates a multiline edit control.
TextComponent A superclass for TextArea and TextField.
TextField Creates a single-line edit control.
Toolkit Abstract class implemented by the AWT.
Window Creates a window with no frame, no menu bar,
Advanced Java Programming -3-
, Chapter 01 Introduction to AWT
Window Fundamentals
The AWT defines windows according to a class hierarchy that adds
functionality and specificity with each level. The two most common windows are
those derived from Panel, which is used by applets, and those derived from
Frame, which creates a standard window. Much of the functionality of these
windows is derived from their parent classes. Thus, a description of the class
hierarchies relating to these two classes is fundamental to their understanding.
Figure below shows the class hierarchy for Panel and Frame.
Component
Container
MenuContainer Window Panel
Interface
Frame Applet
Component
At the top of the AWT hierarchy is the Component class. Component is 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 of Component. 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.
A Component object is responsible for remembering the current foreground and
background colors and the currently selected text font.
Container
The Container class is a subclass of Component. It has additional
methods that allow other Component objects to be nested within it. Other
Container objects can be stored inside of a Container (since they are
themselves instances of Component). This makes for a multileveled
containment system. A container is responsible for laying out (that is,
Advanced Java Programming -4-
