Help is available for each task, or you can go straight to
the solution source code.
Task 1
In the TextEdit constructor skeleton, setup the screen to
have, from top to bottom, a JToolBar, JTextArea,
and JLabel (for status messages). Save a reference to the
JTextArea and JLabel in the instance variables
pane and statusInfo, respectively, as the event
handling methods need access to them. Be sure to place the
JTextArea within a JScrollPane to support
scrolling.
Add to the constructor:
Container content = getContentPane();
JToolBar toolbar = new JToolBar();
content.add (toolbar, BorderLayout.NORTH);
pane = new JTextArea ();
JScrollPane sPane = new JScrollPane (pane);
content.add (sPane, BorderLayout.CENTER);
statusInfo = new JLabel();
content.add (statusInfo, BorderLayout.SOUTH);
Task 2
Set the JToolBar to not be floatable so that it cannot be
dragged outside the frame.
If you prefer to have the toolbar floatable, you can skip this step.
toolbar.setFloatable (false);
Task 3
Create a JMenuBar and add it to the JFrame.
JMenuBar menuBar = new JMenuBar();
setJMenuBar (menuBar);
Task 4
Setup the first menu on the JMenuBar. Create a JMenu
labeled "File" with JMenuItems under it of
"New", "Open", "Save", and "Close".
Place a separator between the "Save" and "Close" entries.
JMenu file = new JMenu ("File");
JMenuItem item;
file.add (item = new JMenuItem ("New"));
file.add (item = new JMenuItem ("Open"));
file.add (item = new JMenuItem ("Save"));
file.addSeparator();
file.add (item = new JMenuItem ("Close"));
menuBar.add (file);
Task 5
Add a keyboard mnemonic to each item. Use the first letter of the label.
At the appropriate location in the source, add the following lines:
file.setMnemonic (KeyEvent.VK_F);
item.setMnemonic (KeyEvent.VK_N);
item.setMnemonic (KeyEvent.VK_O);
item.setMnemonic (KeyEvent.VK_S);
item.setMnemonic (KeyEvent.VK_C);
Task 6
For each JMenuItem, create an anonymous
ActionListener to process the event and
call the appropriate method to handle the event.
-
New -
doNewCommand()
-
Open -
doOpenCommand()
-
Save -
doSaveCommand()
-
Close -
doCloseCommand(statusCode)
At the appropriate location in the source, add the following lines:
item.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doNewCommand();
}
});
...
item.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doOpenCommand();
}
});
...
item.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doSaveCommand();
}
});
...
item.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doCloseCommand (0);
}
});
Task 7
Add the Help JMenu, with the About JMenuItem.
Add a key accelerator for each of 'H' and 'A' respectively. And have the
action handler of the About menu item call doAboutCommand().
JMenu help = new JMenu ("Help");
help.setMnemonic (KeyEvent.VK_H);
help.add (item = new JMenuItem ("About"));
item.setMnemonic (KeyEvent.VK_A);
item.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doAboutCommand();
}
});
menuBar.add (help);
Task 8
In the doAboutCommand() method, create a modal
JDialog named dialog to display the 'About'
information. Have the dialog title be "About...". You will
need to declare the variable final so it will be usable
in the internal event handler.
final JDialog dialog =
new JDialog (this, "About...", true);
Task 9
Once the menus are setup, its time to setup the toolbar. Create four
JButtons to place on the toolbar, labeled New, Open, Save,
and About. Add a separator between Save and About.
JButton jb;
toolbar.add (jb = new JButton ("New"));
toolbar.add (jb = new JButton ("Open"));
toolbar.add (jb = new JButton ("Save"));
toolbar.addSeparator();
toolbar.add (jb = new JButton ("About"));
Task 10
For each button on the toolbar, add a tooltip, with an appropriate message.
At the appropriate location in the source, add the following lines:
jb.setToolTipText ("New File");
jb.setToolTipText ("Open File");
jb.setToolTipText ("Save File");
jb.setToolTipText ("Help - About");
Task 11
For each button, create an anonymous ActionListener to
process the event and call the appropriate method to handle the event.
At the appropriate location in the source, add the following lines:
jb.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doNewCommand();
}
});
...
jb.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doOpenCommand();
}
});
...
jb.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doSaveCommand();
}
});
...
jb.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doAboutCommand();
}
});
Task 12
Save everything and compile the program. Then run it to see the results.
As a precautionary behavior, the Save command appends a "1" to
the end of the filename you desire to save the file as. This attempts to
prevent you from accidently overwriting your source code.
javac TextEdit.java
java TextEdit
If you are using Swing with JDK 1.1.+, make sure your CLASSPATH
environment variable has the swingall.jar file in it.
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MageLang Institute.
All Rights Reserved.
