System, but they may not be reproduced for publication
Yüklə 83 Mb. Pdf görüntüsü
|
| lightweight.
2. Can the look and feel of a Swing component be changed? If so, what feature enables this? Yes. Swing’s pluggable look and feel is the feature that enables this. 3. What is the most commonly used toplevel container for an application? JFrame 4. Toplevel containers have several panes. To what pane are components added? Content pane 5. Show how to construct a label that contains the message "Select an entry from the list". 6. All interaction with GUI components must take place on what thread? eventdispatching thread 7. What is the default action command associated with a JButton? How can the action command be changed? The default action command string is the text shown inside the button. It can be changed by calling setActionCommand( ). 8. What event is generated when a push button is pressed? ActionEvent 9. Show how to create a text field that has 32 columns. 10. Can a JTextField have its action command set? If so, how? Yes, by calling setActionCommand( ). 11. What Swing component creates a check box? What event is generated when a check box is selected or deselected? JCheckBox creates a check box. An ItemEvent is generated when a check box is selected or deselected. 12. JList displays a list of items from which the user can select. True or False? True 13. What event is generated when the user selects or deselects an item in a JList? ListSelectionEvent 14. What method sets the selection mode of a JList? What method obtains the index of the first selected item? setSelectionMode( ) sets the selection mode. getSelectedIndex( ) obtains the index of the first selected item. 15. Add a check box to the file comparer developed in Try This 161 that has the following text: Show position of mismatch. When this box is checked, have the program display the location of the first point in the files at which a mismatch occurs. 16. Change the ListDemo program so that it allows multiple items in the list to be selected. A Appendix B Using Java’s Documentation Comments s explained in Chapter 1 , Java supports three types of comments. The first two are the // and the /* */. The third type is called a documentation comment. It begins with the character sequence /**. It ends with */. Documentation comments allow you to embed information about your program into the program itself. You can then use the javadoc utility program (supplied with the JDK) to extract the information and put it into an HTML file. Documentation comments make it convenient to document your programs. You have almost certainly seen documentation that uses such comments, because that is the way the Java API library was documented. Beginning with JDK 9, javadoc includes support for modules. THE JAVADOC TAGS y History Topics Tutorials Offers & Deals Highlights Settings Support Sign Out THE JAVADOC TAGS The javadoc utility recognizes several tags, including those shown here: Document tags that begin with an “at” sign (@) are called standalone tags (also called Yüklə 83 Mb. Dostları ilə paylaş:
|