Event Handling in Programming

Event Handling

• Event: an occurrence that triggers a response from the program
• Event Source: the object that generates the event (e.g. button click)
• Event Listener: the object that responds to the event
• Event Handler: the method that handles the event

Types of events:

• ActionEvent: generated by button clicks, menu selections, etc.
• MouseEvent: generated by mouse clicks, movements, etc.
• KeyEvent: generated by keyboard input
• WindowEvent: generated by window-related actions (e.g. closing, resizing)

How to handle events:

• Implement the EventListener interface
• Register the event listener with the event source using addActionListener(), addMouseListener(), etc.
• Define the event handler method (e.g. actionPerformed())

Layout Management

• Layout Manager: responsible for arranging components in a container
• Layout Constraints: rules that govern how components are arranged

Common layout managers:

• BorderLayout: divides container into five regions (north, south, east, west, center)
• FlowLayout: arranges components in a row or column
• GridLayout: arranges components in a grid
• GridBagLayout: arranges components in a grid with flexible sizing

How to use layout managers:

• Create a layout manager instance
• Set the layout manager for a container using setLayout()
• Add components to the container with specific layout constraints

Swing Components

• JComponent: base class for all Swing components
• JPanel: a generic container component
• JButton: a button component
• JLabel: a label component
• JTextField: a single-line text field component

Common Swing components:

• JFrame: a top-level window component
• JDialog: a dialog box component
• JMenu: a menu component
• JTable: a table component
• JTree: a tree component

GUI Design Patterns

• Model-View-Controller (MVC): separates application logic into three interconnected components
  • Model: represents the application data and business logic
  • View: represents the GUI components and layout
  • Controller: handles user input and updates the model and view
• Observer Pattern: allows objects to notify each other of changes
• Factory Pattern: provides a way to create objects without specifying their concrete classes

JavaFX Basics

• JavaFX: a Java library for building GUI applications
• Scene: the top-level container for a JavaFX application
• Stage: a window that contains a scene
• Node: a component in a scene graph (e.g. button, label, text field)

Common JavaFX components:

• Button: a button component
• Label: a label component
• TextField: a single-line text field component
• ListView: a list component
• ImageView: an image component

How to create a JavaFX application:

• Create a Stage instance
• Create a Scene instance and set it to the stage
• Add nodes to the scene graph using getChildren().add()
• Show the stage using show()

Event Handling

• An Event is an occurrence that triggers a response from the program.
• An Event Source is the object that generates the event, such as a button click.
• An Event Listener is the object that responds to the event.
• An Event Handler is the method that handles the event.

Event Types

• ActionEvent: generated by button clicks, menu selections, etc.
• MouseEvent: generated by mouse clicks, movements, etc.
• KeyEvent: generated by keyboard input.
• WindowEvent: generated by window-related actions, such as closing or resizing.

Handling Events

• Implement the EventListener interface.
• Register the event listener with the event source using methods like addActionListener() or addMouseListener().
• Define the event handler method, such as actionPerformed().

Layout Management

• A Layout Manager is responsible for arranging components in a container.
• Layout Constraints are rules that govern how components are arranged.

Common Layout Managers

• BorderLayout: divides container into five regions (north, south, east, west, center).
• FlowLayout: arranges components in a row or column.
• GridLayout: arranges components in a grid.
• GridBagLayout: arranges components in a grid with flexible sizing.

Using Layout Managers

• Create a layout manager instance.
• Set the layout manager for a container using setLayout().
• Add components to the container with specific layout constraints.

Swing Components

• JComponent: the base class for all Swing components.
• JPanel: a generic container component.
• JButton: a button component.
• JLabel: a label component.
• JTextField: a single-line text field component.

Common Swing Components

• JFrame: a top-level window component.
• JDialog: a dialog box component.
• JMenu: a menu component.
• JTable: a table component.
• JTree: a tree component.

GUI Design Patterns

• Model-View-Controller (MVC): separates application logic into three interconnected components.
  • Model: represents the application data and business logic.
  • View: represents the GUI components and layout.
  • Controller: handles user input and updates the model and view.
• Observer Pattern: allows objects to notify each other of changes.
• Factory Pattern: provides a way to create objects without specifying their concrete classes.

JavaFX Basics

• JavaFX: a Java library for building GUI applications.
• Scene: the top-level container for a JavaFX application.
• Stage: a window that contains a scene.
• Node: a component in a scene graph, such as a button, label, or text field.

Common JavaFX Components

• Button: a button component.
• Label: a label component.
• TextField: a single-line text field component.
• ListView: a list component.
• ImageView: an image component.

Creating a JavaFX Application

• Create a Stage instance.
• Create a Scene instance and set it to the stage.
• Add nodes to the scene graph using getChildren().add().
• Show the stage using show().

Understanding the concepts of event handling, including events, event sources, listeners, and handlers, as well as different types of events such as ActionEvent, MouseEvent, and KeyEvent.