Graphical User Interface Components

1
Graphical User Interface Components
The Sequal

• Chapter 14

2
What You Will Learn

• Text Areas
• Sliders
• Menus
• With frames
• Pop up menus
• Look and feel options

3
JTextArea

• Area for manipulating multiple lines of text
• Extends JTextComponent
• Inherits from that class
• View Figure 14.1
• Note
• Creation of box
• Creation of two JTextArea objects
• Copy of marked text to other text area

4
Subclass of JPanel

• A JPanel can
• Aggregate a set of GUI components
• Create dedicated drawing areas
• Create areas that receive mouse events
• Subclass of a JPanel should
• Override method paintComponent
• Call the superclass version as first statement
• Note the customized JPanel subclass, Figure 14.2

5
Demonstration of Customized JPanel

• Now view Figure 14.3
• Note
• Declaration, instantiation of the CustomPanel
• Method draw used in actionPerformed methods

6
Another Customized JPanel Class

• Possible for the (sub)class to handle its own
  events
• Note SelfContainedPanel class, Figure 14.4
• This class has
• Mouse activity handlers
• Preferred dimension specified
• Call to paintComponent method
• Figure 14.5 uses this customized subclass

7
JSliders

• Enable users to select from range of integer
  values
• Features
• Tick marks (major and minor)
• Snap-to ticks
• Orientation (horizontal and vertical)

thumb
8
JSliders

• JPanel subclass for drawing circles, Figure 14.7
• JSlider used to control size of a circle graphic,
  Figure 14.8
• Note
• Slider declaration, implementation
• Registration of listener for the slider

9
Using Menus with Frames

• Allows for performing actions with cluttering GUI
• Contained by menu bar JMenuBar
• Comprised of menu items MenuItem
• Note Figure 14.9
• Declares menu items
• Populates the menus
• Specifies actions for menu choices

10
JPopupMenu

• Menus that are context-sensitive
• Right click and popup menu appears
• In Swing, use JPopupMenu
• Provide options specific to component
• Popup trigger event occurs when object right
  mouse clicked
• Demonstration of JPopupMenu shown in Figure 14.10

11
Pluggable Look-and-Feel

• Recall that Java is designed to run on variety of
  platforms
• GUI components on a Mac, look different from
  those on a PC or on a UNIX platform
• Look-and-Feel capability
• Java program on a particular platform looks like
  other programs on the same platform
• Also possible to specify the look-and-feel of a
  Swing GUI

12
Pluggable Look-and-Feel

• Figure 14.11 demonstrates how to change the
  appearance
• Note use of UIManager methods

13
JDesktopPane and JInternalFrame

• Multiple document interface
• Main (parent) window
• Child windows
• View Figure 14.12 which demonstrates this
• Note
• Declaration, instantiation of JDesktopPane object
• Choosing and painting of the icons

14
JTabbedPane

• Arranges GUI components into layers
• One layer visible at a time
• Access each layer via a tab
• View tab demo program, Figure 14.13
• Note
• declaration of tabbed panes

15
Layout Managers

• BoxLayout arranges GUI components
• Horizontally along x-axis
• Vertically along y-axis

16
BoxLayout

• Demonstrated in Figure 14.15
• Also uses the tabs
• Offers several different options for laying out
  three JButtons
• Note
• Creation of boxes
• Adding of buttons

17
GridBagLayout Layout Manager

• Flexible GridBagLayout
• Components can vary in size
• Components can occupy multiple rows and columns
• Components can be added in any order
• Uses GridBagConstraints
• Specifies how component is placed in
  GridBagLayout

18
GridBagLayout Layout Manager

• GridBagConstraints fields

19
GridBagLayout Layout Manager

• Designing a GUI to use the GridBagLayout
• Program for this layout demonstrated in Figure
  14.19

Column
0
1
2
0
1
Row
2
3
20
GridBagLayout Layout Manager

• Variation of GridBagLayout does not use gridx and
  gridy
• Use constants RELATIVE and REMAINDER
• RELATIVE
• Specifies next-to-last component placement in row
  or column
• Component placed next to one previously added
• REMAINDER
• Specifies component as last component in row or
  column

21
GridBagLayout Layout Manager

• Use of constraints demonstrated inFigure 14.20
• Note
• Setting constraint weights
• Setting grid width
• Adding buttons
• The addComponent method