Easy Notes Of Java programming unit-4 @Computer Diploma

Description

4.1 AWT Components & Containers

• Component: The base class for all AWT user interface elements.
• Container: A subclass of Component that can hold other components.
• Window: A top-level container with no borders or menu bar.
• Frame: A top-level window with a title, borders, and a menu bar.
• Panel: A simple container used to group components.
• AWT Controls: Label (display text), Button (clickable control), Checkbox (on/off option), CheckboxGroup (radio buttons), TextField (single-line text input), TextArea (multi-line text input).

4.2 Layout Managers

• Layout Managers: Objects that automatically arrange components within a container.
• FlowLayout: Arranges components in a row, like a line of text.
• BorderLayout: Divides the container into five regions: North, South, East, West, and Center.
• GridLayout: Arranges components in a grid of rows and columns.
• GridBagLayout: A flexible layout manager that aligns components based on a grid of cells.
• Menu Components: MenuBar (holds menus), Menu (a list of menu items), MenuItem (an item in a menu), FileDialog (a dialog for opening or saving files).

4.3 Introduction to Swing

• Swing: A more modern and flexible GUI toolkit built on AWT.
• Swing Features: Lightweight components (platform-independent), Pluggable Look and Feel, richer set of components.
• AWT vs. Swing: AWT components are heavyweight (rely on native OS components). Swing components are lightweight (drawn by Java itself).

4.4 Swing Components

• JLabel: Displays a short string of text or an image. Can include Icons.
• JTextField: Single-line text input field.
• JComboBox: Drop-down list or editable field.
• JButton: Clickable button.
• JCheckBox: On/off option.
• JRadioButton: A choice within a mutually exclusive group, managed by a ButtonGroup.

4.5 Advanced Swing Components

• JTabbedPane: A component that lets you switch between different panels using tabs.
• JScrollPane: Adds scrollbars to a component, like a text area or a table, when its content exceeds the visible area.
• JTree: Displays hierarchical data, like files in a directory.
• JTable: Displays data in a tabular format (rows and columns).
• JProgressBar: A visual indicator of the progress of a task.
• JToolTip: A small pop-up window that appears when the mouse hovers over a component.

4.6 Introduction to Event Handling

• Delegation Event Model: A design pattern where an object (the event source) generates an event, and another object (the event listener) receives and handles it.
• Event Sources: Objects that generate events (e.g., a button).
• Event Listeners: Objects that “listen” for and handle specific events.

4.7 Event Classes

• ActionEvent: Generated when a button is clicked or a menu item is selected.
• ItemEvent: Generated when a checkbox or radio button’s state changes.
• KeyEvent: Generated when a key is pressed, released, or typed.
• MouseEvent: Generated when the mouse is clicked, moved, or enters/exits a component.
• TextEvent: Generated when the text within a text component changes.

4.8 Event Listener Interfaces

• ActionListener: Handles ActionEvent.
• ItemListener: Handles ItemEvent.
• KeyListener: Handles KeyEvent.
• MouseListener: Handles MouseEvent (clicks, presses, releases).
• MouseMotionListener: Handles MouseEvent (movement, dragging).
• TextListener: Handles TextEvent.