CIS525 - Lecture#16 - October 30, 2000
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CIS 525 10/30/00
many questions re: Java assignent...
...Dilbert today: "The Smart-Alek Intern"
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menus:
page 549, ColorMenu.java
1) create new menu bar
2) create menu with names
3) add strings or other menus
4) add menu to menu bar
5) show
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Serialization: Java 1.1
page 553
save the state of Java objects or broadcast over network
- make sure all objects referenced by windows are 'serializable', (use interface), all awt
objects are serializable
writing a window to disk:
try{
fileOutputStream fileOut = new FileOutStream("_");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(SomeWindow);
out.flush();
out.close();
} catch(IOException ioe) {
System.out.println("Error saving window: " + ioe);
}
On page 554, reading window from disk:
try {
File saveFile = new File("SaveFilename:);
FileInputStream fileIn = new FileInputStream(saveFile);
ObjectInputStream in = new ObjectInputStream(fileIn);
SomeWindow = (WindowType)in.readObject();
doSomethingWith(someWindow);
gzipInputStream() for compressed files
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Dialog - Page 559:
- specialized frame
modal or not modal, modal = all action freezes until some response is registered
- default layout manager is BorderLayout
creating and using:
1) modal or not
2) to use from applets, getFrame()
See Page 561 Confirm.java
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File dialog - Page 563:
modal, (save or load files)
no default layout manager
=> not a container object
creating and using:
1) make file dialog
fileDialog fileLoader = new FileDialog(frame, title, FileDialog.LOAD);
FileDialog fileSaver = new FileDialog(frame, title, FileDialog.SAVE);
2) set default file or type
fileLoader getFile("*.txt");
3) pop-up fileDialog
fileLoader.show();
4) look up the file name
String fileName = fileLoader.getFile();
See Page 565-568, DisplayFile.java
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Windows - page 571:
- pop up application
no title
Fixed size window - Page 569:
1) create window
2) add component()
3) resize window (stretch pack)
4) display window (stretch pack)
Popup.java page 571
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Next lecture: Layout Managers, Chapter 12
1) flow layout
2) border layout
3) grid layout
4) card layout
5) grid bag layout
consider nesting each container object so each has a layout manager
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