如何使用 Java AWT setBackground

Question

This is some code to create a basic java window:

JPanel pane = new JPanel();
gui(String title){
    super(title);
    setBounds(100,100,500,500);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container con = this.getContentPane();
*   con.setBackground(new Color(0,0,0));
    con.add(pane);
    setVisible(true);
}

The line marked with a star (*) is meant to make the window's background color black (0,0,0). However, that line seems to do nothing. (I have tried using pane.setBackground here, but that made no diffference.)

How do I change the background color?

Answer 1

You have added the JPanel over the JFrame which completely blocks out the underlying container on which you have set the color.

You could do this instead:

public Gui(String title) {
   super(title);
   JPanel pane = new JPanel();
   setBounds(100, 100, 500, 500);
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   Container con = this.getContentPane();
   pane.setBackground(new Color(0, 0, 0));
   con.add(pane);
   setVisible(true);
}

Answer 2

You can't set the background color for a JFrame's content pane. By that I meant:

 JFrame f = new JFrame() ;
 f.setBackground(Color.RED) ;

What you should do however is create a JPanel that will act as your background and set its color like so:

backgroundPanel.setBackground(Color.RED);

Answer 3

Jframe f =new Jframe();
f.setBackground(Color.red);

This may also solve the Problem in hand.