Task 1
Create class DirectoryList
as subclass of Frame
.
In the constructor, set the size to 400 x 500, create the list box in the north
position, add the elements passed in to the constructor, and create a text area
in the center position.
Use setSize()
to set the size of the Frame
.
The components are added in the same manner as with an applet (a Frame
is a specialized Container
, as is an Applet
).
Task 2
Add the following code to DirectoryList
so that you can shut
down the application window:
import java.awt.event.*;
...
// handle the WINDOW events here
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent event) {
setVisible(false);
dispose();
System.exit(0);
}
});
Task 3
Add an actionPerformed()
method to handle selection of the list
elements. Upon selection (with a double-click operation), call displayFile()
with the filename selected.
You should check to see that the component that caused the event was indeed
the list box. Use an expression such as e.getSource() == list
.
Also, you should retrieve the selected item with list.getSelectedItem()
,
ensuring that the value returned is not null
.