This exercise produces an application rather than an applet. This application should be run from the command line rather than from a page in a browser. (Applets cannot do file I/O for security reasons.)

Open a Frame with a list box and a text area. Using routines provided for you, display the list of files in the current directory in the list box. When the user double-clicks on an entry, display that file in the text area.

Skeleton Code

• DirectoryList.java
• DisplayFile.java

Tasks

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.

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);
     }
   });
   

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.

Where help exists, the task numbers above are linked to the step-by-step help page.

Solution Source

• DisplayFile.java
• DirectoryList.java

Demonstration

This program cannot be run as an applet as it uses file I/O. Please run the solution from the command line as an application, or from an IDE window.

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