1. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 1 Chapter 13 Creating User Interfaces Chapter 11 Getting Started with GUI Programming Chapter 8 Inheritance and Polymorphism Chapter 13 Creating User Interfaces Chapter 14 Applets, Images, Audio Chapter 9 Abstract Classes and Interfaces Chapter 12 Event-Driven Programming

2. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 2 Objectives F To create graphical user interfaces with various user-interface components: JButton, JCheckBox, JRadioButton, JLabel, JTextField, JTextArea, JComboBox, JList, JScrollBar, and JSlider (§13.2 – 13.12). F To create listeners for various types of events (§13.2 – 13.12). F To use borders to visually group user-interface components (§13.2). F To create image icons using the ImageIcon class (§13.3). F To display multiple windows in an application (§13.13).

3. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 3 Components Covered in the Chapter F Introduces the frequently used GUI components F Uses borders and icons

4. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 4 Borders You can set a border on any object of the JComponent class. Swing has several types of borders. To create a titled border, use new TitledBorder(String title). To create a line border, use new LineBorder(Color color, int width), where width specifies the thickness of the line. For example, the following code displays a titled border on a panel: JPanel panel = new JPanel(); panel.setBorder(new TitleBorder(“My Panel”));

5. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 5 Test Swing Common Features Component Properties F font F background F foreground F preferredSize F minimumSize F maximumSize JComponent Properties F toolTipText F border TestSwingCommonFeatures

6. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 6 Buttons A button is a component that triggers an action event when clicked. Swing provides regular buttons, toggle buttons, check box buttons, and radio buttons. The common features of these buttons are represented in javax.swing.AbstractButton.

7. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 7 JButton JButton inherits AbstractButton and provides several constructors to create buttons.

8. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 8 Icons An icon is a fixed-size picture; typically it is small and used to decorate components. javax.swing.Icon is an interface. To create an image, use its concrete class javax.swing.ImageIcon. For example, the following statement creates an icon from an image file: Icon icon = new ImageIcon("photo.gif"); TestButtonIcons

9. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 9 Default Icons, Pressed Icon, and Rollover Icon A regular button has a default icon, pressed icon, and rollover icon. Normally, you use the default icon. All other icons are for special effects. A pressed icon is displayed when a button is pressed and a rollover icon is displayed when the mouse is over the button but pressed. (A) Default icon (B) Pressed icon (C) Rollover icon

10. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 10 Horizontal Alignments Horizontal alignment specifies how the icon and text are placed horizontally on a button. You can set the horizontal alignment using one of the five constants: LEADING, LEFT, CENTER, RIGHT, TRAILING. At present, LEADING and LEFT are the same and TRAILING and RIGHT are the same. Future implementation may distinguish them. The default horizontal alignment is SwingConstants.TRAILING.

11. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 11 Vertical Alignments Vertical alignment specifies how the icon and text are placed vertically on a button. You can set the vertical alignment using one of the three constants: TOP, CENTER, BOTTOM. The default vertical alignment is SwingConstants.CENTER.

12. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 12 Horizontal Text Positions Horizontal text position specifies the horizontal position of the text relative to the icon. You can set the horizontal text position using one of the five constants: LEADING, LEFT, CENTER, RIGHT, TRAILING. The default horizontal text position is SwingConstants.RIGHT.

13. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 13 Vertical Text Positions Vertical text position specifies the vertical position of the text relative to the icon. You can set the vertical text position using one of the three constants: TOP, CENTER. The default vertical text position is SwingConstants.CENTER.

14. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 14 Example 13.1: Using Buttons Write a program that displays a message on a panel and uses two buttons,, to move the message on the panel to the left or right. ButtonDemo

15. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 15 JCheckBox JCheckBox inherits all the properties such as text, icon, mnemonic, verticalAlignment, horizontalAlignment, horizontalTextPosition, verticalTextPosition, and selected from AbstractButton, and provides several constructors to create check boxes.

16. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 16 Example 13.2: Using Check Boxes Add three check boxes named Centered, Bold, and Italic into Example 13.1 to let the user specify whether the message is centered, bold, or italic. CheckBoxDemo ButtonDemo CheckBoxDemo

17. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 17 JRadioButton Radio buttons are variations of check boxes. They are often used in the group, where only one button is checked at a time.

18. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 18 Grouping Radio Buttons ButtonGroup btg = new ButtonGroup(); btg.add(jrb1); btg.add(jrb2);

19. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 19 Example 13.3: Using Radio Buttons Add three radio buttons named Red, Green, and Blue into the preceding example to let the user choose the color of the message. RadioButtonDemo ButtonDemo CheckBoxDemo RadioButtonDemo

20. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 20 JLabel A label is a display area for a short text, an image, or both.

21. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 21 Using Labels // Create an image icon from image file ImageIcon icon = new ImageIcon("image/grapes.gif"); // Create a label with text, an icon, // with centered horizontal alignment JLabel jlbl = new JLabel("Grapes", icon, SwingConstants.CENTER); // Set label's text alignment and gap between text and icon jlbl.setHorizontalTextPosition(SwingConstants.CENTER); jlbl.setVerticalTextPosition(SwingConstants.BOTTOM); jlbl.setIconTextGap(5);

22. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 22 JTextField A text field is an input area where the user can type in characters. Text fields are useful in that they enable the user to enter in variable data (such as a name or a description).

23. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 23 Example 13.4: Using Text Fields Add a text field to the preceding example to let the user set a new message. TextFieldDemo

24. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 24 JTextArea If you want to let the user enter multiple lines of text, you cannot use text fields unless you create several of them. The solution is to use JTextArea, which enables the user to enter multiple lines of text.

25. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 25 Example 13.5 Using Text Areas  This example gives a program that displays an image in a label, a title in a label, and a text in a text area.

26. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 26 Example 13.5, cont. TextAreaDemo

27. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 27 JComboBox A combo box is a simple list of items from which the user can choose. It performs basically the same function as a list, but can get only one value.

28. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 28 Using the itemStateChanged Handler public void itemStateChanged(ItemEvent e) { // Make sure the source is a combo box if (e.getSource() instanceof JComboBox) String s = (String)e.getItem(); } When a choice is checked or unchecked, itemStateChanged() for ItemEvent is invoked as well as the actionPerformed() handler for ActionEvent.

29. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 29 Example 13.6: Using Combo Boxes This example lets users view an image and a description of a country's flag by selecting the country from a combo box. ComboBoxDemo

30. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 30 JList A list is a component that performs basically the same function as a combo box, but it enables the user to choose a single value or multiple values.

31. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 31 Example 13.7: Using Lists This example gives a program that lets users select countries in a list and display the flags of the selected countries in the labels. ListDemo

32. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 32 JScrollBar A scroll bar is a control that enables the user to select from a range of values. The scrollbar appears in two styles: horizontal and vertical.

33. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 33 Scroll Bar Properties

34. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 34 Example 13.8: Using Scrollbars This example uses horizontal and vertical scrollbars to control a message displayed on a panel. The horizontal scrollbar is used to move the message to the left or the right, and the vertical scrollbar to move it up and down. ScrollBarDemo

35. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 35 JSlider JSlider is similar to JScrollBar, but JSlider has more properties and can appear in many forms.

36. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 36 Example 13.9: Using Sliders Rewrite the preceding program using the sliders to control a message displayed on a panel instead of using scroll bars. SliderDemo

37. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 37 Creating Additional Windows, Step 4 Step 4: Override the actionPerformed() method as follows: public actionPerformed(ActionEvent e) { String actionCommand = e.getActionCommand(); if (e.target instanceof Button) { if ("Activate SubFrame".equals(actionCommand)) { subFrame.setVisible(true); }

38. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 38 Example 13.10 Creating Multiple Windows F This example creates a main window with a text area in the scroll pane, and a button named "Show Histogram." When the user clicks the button, a new window appears that displays a histogram to show the occurrence of the letters in the text area.

39. Liang, Introduction to Java Programming, Fifth Edition, (c) 2005 Pearson Education, Inc. All rights reserved. 0-13-148952-6 39 Example 13.10, cont. MultipleWindowsDemo Histogram