Changing the Color of a Frame

We will fill in the actionPerformed() body so that clicking the button changes the color of the frame. To change the color of the frame, do this:

getContentPane().setBackground( Color.blue )

A JFrame is a complicated object made up of many parts. The frame's content pane is where components added to the frame are displayed. The getContentPane() method of the frame returns a reference to the content pane. The setBackground() method of the pane changes its background color.

Other predefined colors are Color.green, Color.blue, Color.yellow, and so on. (Look in your Java documentation under the class Color to find more.) Here is the interesting part of our program:

class ButtonFrame2 extends JFrame implements ActionListener
{
  JButton bChange ;

  // constructor   
  public ButtonFrame2() 
  {
   . . . 
  }
   
  public void actionPerformed( ActionEvent evt)
  {
     ;
    
    repaint();  // ask the system to paint the screen.
  }
  
}