1. CIS 270—Application Development II Chapter 11—GUI Components: Part I

2. 2 11.1 Introduction GUI (graphical user ___________) GUI ____________: An object with which the user interacts. label text field button text area combo box menu

3. 3 11.2 JOptionPane A dialog box (or just dialog) is an application window. The JOptionPane class in the javax._______ package provides simple dialogs for input / output (Fig. 11.2). String numberStr = JOptionPane.showInputDialog (“Enter first integer”); JOptionPane.showMessageDialog (null, “The sum is” + sum, “Sum of Two Integers”, JOptionPane.PLAIN_MESSAGE); The input dialog can input only ________. A string of numeric characters must be converted to a number. int number = Integer.parseInt(numberStr);

4. 4 11.3 Overview of Swing Components Most applications need more than simple I/O dialogs. Before Java 1.2, AWT (_________ Windows Toolkit) was used to create GUIs, but these were platform dependent (heavyweight components). Most Swing components are platform independent (__________) components (pure Java, part of JFC). The inheritance hierarchy for Java GUIs is Object  Component  Container  JComponent JComponent is the superclass of all Swing lightweight components.

5. 5 11.4 Text/Images in a Window JFrame object: A window with a _______ bar and min/max/close buttons. JLabel object: Provides a single line of read-only text, an image, or both text and image. Steps in creating a GUI (see Figs. 11.6 and 11.7): import required classes create a container class (subclass of _________) declare components in the container class create a constructor for the container set the layout instantiate the components set component properties add components to container create an application class that instantiates the container

6. 6 11.5 Introduction to Event Handling GUIs are _______ driven. An event is a user interaction with a GUI component. An event handler is code that performs a task in response to an event. A JTextField object can receive text input. A JPasswordField object does likewise, but hides the input with an ______ character. A component receives _______ when a user clicks on it. Additional steps for event handling (see Figs. 11.9 and 11.10): in the container constructor instantiate an event-handler object register the component with the event-handler using addActionListener create a nested event-handler class that provides functionality

7. 7 11.6-7 Events, Interfaces, and Event Handling Three objects in the event-handling mechanism: event source object (creates the event object) event ________ (contains info about the event) event listener object (receives the event object) Registering an event source object with an event listener object: textField1.addActionListener( handler ); When an ActionEvent object is created, the JVM dispatches that object to every actionPerformed method (in the interface _________________) with which the event object is registered.

8. 8 11.8 JButton Types of buttons command, check box, toggle, radio The class AbstractButton declares common features of Swing buttons. Command buttons create _______________ objects when clicked. A JButton object (command button) can call the setRolloverIcon method. (Fig. 11.15)

9. 9 11.9 Buttons That Maintain State Three kinds of button have state (on/off or true/false status) JToggleButton, JCheckBox, JRadioButton When a JCheckBox object is clicked, an _____________ object is created and is handled by an ItemListener object, which calls the itemStateChanged method. JRadioButton objects represent mutually exclusive options (only one in a group can be selected). JRadioButton objects must be added to a ______________ object.

10. 10 11.10-12 Review the programs in these sections.

11. 11 11.17-18 Layout Managers Three ways to arrange components in a GUI: _________ positioning—specify size and position of each layout managers—easier than absolute, but control is lost visual programming w/ an _____—drag, drop, resize, etc. Layout managers arrange GUI components in a container for presentation purposes. Types of layout managers FlowLayout— simplest, components flow left to right ___________—arranges components into five regions GridLayout— components are placed in an r x c grid Complex layouts are possible by using a JPanel as a component that holds other components