Top-level Window JFrame

      import java.awt.*;
      import java.awt.event.*;
      import javax.swing.*;
      
      public class TopLevelWindow {
        public static void main(String[] args) {
          MyFrame frame = new MyFrame(); 
        }
      }
      
      class MyFrame extends JFrame {
        ...
      }
    

Description and Objective

• This is a simple application which changes the background color of the app window everytime it gains focus.

Things to Do

• Use the above code as a template and implement the c'tor of MyFrame class as follows:
  • set the size of the window
  • set the position of the window
  • set the title of the window to "Lab 5 - Part 1"
  • create and add a FocusListener object which changes the background color of the JFrame. The background color should cycle between red, green, blue and cyan.
  • make sure that when you close the window the application quits also (use setDefaultCloseOperation)
  • set the window visible
• To test the behaviour of the application, open another window (e.g. windows explorer, any browser etc.) and switch back and forth by selecting the other window and the app window.