1. Advanced GUIs II CS
Lecture 9-1 1

2. Agenda Scrollbars Frames and applications Popup menus Layout managers
CardLayout
GridBagLayout

3. Scrollbars Use Scrollbars two ways:
Add scrollbars to components
Use standalone as "sliders"
Scrollbar objects are Components which implement Adjustable interface
For objects with adjustable numeric value contained within a bounded range

4. What Scrollbars Need to Know
Minimum value
Maximum
Horizontal or vertical orientation
Delta for blocks and units
Proportion viewed at one time

5. Scrollbar Tips
Visible amount scroll bar is portion of total visible at one time
Scrollbar's value can't exceed max minus scroll box size:
minimum <= adjustableValue <= maximum - visible

6. Frames Applets run within a host application Other Containers
Host provides the window
Applets are Panels, which are Containers\
Other Containers
ScrollPane
Window
Frame IS-A Window
Frame = Window title + border

7. Frames are Handy to Have
Use Frames to build standalone GUI applications
Applets can use Frames too (pops up a new window)

8. Frame Tips Frames don't display by default
Call the Frame object's setVisible() method with a true argument
Frames don't have a default size
Better call setSize() on the Frame object
Default layout is BorderLayout
Windows have events, which Frames inherit

9. Window Events Windows implement WindowListener
windowActivated(WindowEvent)
Invoked when a window is activated.
windowClosed(WindowEvent)
Invoked when a window has been closed.
windowClosing(WindowEvent)
Invoked when a window is in the process of being closed.
windowDeactivated(WindowEvent)
Invoked when a window is de-activated.
windowDeiconified(WindowEvent)
Invoked when a window is de-iconified.
windowIconified(WindowEvent)
Invoked when a window is iconified.
windowOpened(WindowEvent)
Invoked when a window has been opened.

10. Double-Duty: Applets and Applications
Applications are similar to Applets, but have a main() method (like C & C++)
Applications don't have a host window, so create one

11. Building Your Own Browser
Write an applet which has a main()
main() creates a host window (a Frame)
Invokes the Applet inside the newly created Frame

12. Example of Appletication
// Allow this applet to run as an application also
public static void main( String args[] ) {
// create application Frame and resize
Frame app = new Frame( "Application" );
app.setSize( 300, 100 );
// register window handler to terminate application
app.addWindowListener( new CloseWindowAndExit() );
// create applet instance
MyFrame m = new MyFrame();
// initialize and start the applet
m.init();
m.start();
// add applet to center of Frame
app.add( m, BorderLayout.CENTER );
// display the frame (everything attached is painted)
app.setVisible( true ); }

13. What's on the Menu?
Applets don't have menus, because they don't have menu bars
Frames can have menu bars
Menus are:
Good because they "clean up" the interface and unclutter it
Bad because they often hide much functionality

14. Menus in Java Menu bar is the thingie that menus drop down from
Menu item is a string inside a menu that causes an action to be performed when selected
Action or another menu

15. Frames and Menus in Action
Title bar
MenuItem
Menu
Menubar

16. ScratchPad Application
Lets users type text and change font and color
Prevent typing by choosing read-only

17. Dialogs Dialogs are Windows with titles
Common for passing information to user
Two kinds
Modal: Can't escape
Non-modal (or modeless): Can be ignored

18. Popup Menus
Popup menus can be attached to any Component (works for applets too!)
Different platforms have different popup menu gestures
When the AWT detects that a mouse event is the popup trigger event, it tags the event (remember MouseEvent.isPopupTrigger()?)

19. Layout Managers More layout managers
CardLayout: "Stacks" several layouts on top of one another
GridBagLayout: Like GridLayout, but more flexible (read more complex)