Question

How would one go about getting the z order (layer depth of ) all the JInternalFrames inside a JDesktopPane. There does not seem to be a straight forward way for this. Any ideas?

Answer 1

Although I haven’t tried this, the Container class (which is an ancestor of the JDesktopPane class) contains a getComponentZOrder method. By passing a Component which is in the Container, it will return the z-order of as an int. The Component with the lowest z-order value returned by the method is drawn last, in other words, is drawn on top.

Coupling with the JDesktopPane.getAllFrames method, which returns an array of JInternalFrames, I would think that one could obtain the z-order of the internal frames.

Edit

I’ve actually tried it out and it seems to work:

final JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  final JDesktopPane desktopPane = new JDesktopPane(); desktopPane.add(new JInternalFrame('1') {     {         setVisible(true);         setSize(100, 100);     } }); desktopPane.add(new JInternalFrame('2') {     {         setVisible(true);         setSize(100, 100);     } }); desktopPane.add(new JInternalFrame('3') {     JButton b = new JButton('Get z-order');     {         setVisible(true);         setSize(100, 100);         getContentPane().add(b);         b.addActionListener(new ActionListener() {             public void actionPerformed(ActionEvent e)             {                 JInternalFrame[] iframes = desktopPane.getAllFrames();                 for (JInternalFrame iframe : iframes)                 {                     System.out.println(iframe + '\t' +                             desktopPane.getComponentZOrder(iframe));                 }             }         });     } });  f.setContentPane(desktopPane); f.setLocation(100, 100); f.setSize(400, 400); f.validate(); f.setVisible(true); 

In the above example, a JDesktopPane is populated with three JInternalFrames with the third one having a button which will output a list of JInternalFrames and its z-order to System.out.

An example output is the following:

JDesktopPaneTest$3[... tons of info on the frame ...]    0 JDesktopPaneTest$2[... tons of info on the frame ...]    1 JDesktopPaneTest$1[... tons of info on the frame ...]    2 

The example uses a lot of anonymous inner classes just to keep the code short, but an actual program probably should not do that.