Get current display size in Java

Question

I want to get the resolution for the screen the window is currently located in. So if I drag the window from one display to another with a different resolution the application should be able to change.

I'm running this on a thinkpad running ubuntu gnome connected to a external screen.

Here're my current attempts:

import java.awt.Dimension;
import java.awt.DisplayMode;
import java.awt.GraphicsEnvironment;
import java.awt.Toolkit;

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class sizetest {

   void run() {
      Display display = new Display();
      Shell shell = new Shell(display);
      shell.setText("sizetest");
      shell.pack();
      shell.open();

      while (!shell.isDisposed()) {
         DisplayMode mode = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDisplayMode();
         System.out.println(String.format("Current environment screensize: %s, %s", mode.getWidth(), mode.getHeight()));
         Dimension current = Toolkit.getDefaultToolkit().getScreenSize();
         System.out.println(String.format("Current toolkit screensize: %s, %s", current.getWidth(), current.getHeight()));
         Rectangle bounds = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration().getBounds();
         System.out.println(String.format("Bounds %s, %s", bounds.width, bounds.height));
         if (!display.readAndDispatch()) {
            display.sleep();
         }
      }
      display.dispose();
   }

   public static void main(String[] args) {
      sizetest o = new sizetest();
      o.run();
   }
}

Output is

Current environment screensize: 1920, 1080
Current toolkit screensize: 3840.0, 3240.0 
Bounds 1920, 1080

Neither of them change when I move the window from one screen to the other.

[check this](http://stackoverflow.com/questions/3680221/how-can-i-get-the-monitor-size-in-java) — Jordi Castilla, Sep 14 '15 at 08:24
@JordiCastilla Added third method from the answer by jan, that too didn't work. — dutt, Sep 14 '15 at 08:32
I don't know how you old Abel to do it directly with SWT, but you could check to see if anynofnthe given GraphicsDevices's contains the window (by comparing bounds) — MadProgrammer, Sep 14 '15 at 09:00

score 2 · Accepted Answer · answered Sep 14 '15 at 08:52

If you have an AWT/Swing window, you can query its GraphicsConfiguration to get what you want. Note that the different parts of the window can be located on several displays at a time. This method returns the display where the the window center is located. Here's simple component which displays the size of its current display:

public class TestFrame extends JFrame {
    JLabel label = new JLabel();

    public TestFrame() {
        super("Resolution tracker");
        setSize(300, 50);
        add(label);
        updateResolution();
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        addComponentListener(new ComponentAdapter() {
            @Override
            public void componentMoved(ComponentEvent e) {
                updateResolution();
            }
        });
    }

    protected void updateResolution() {
        DisplayMode mode = this.getGraphicsConfiguration().getDevice().getDisplayMode();
        label.setText(mode.getWidth()+" x "+mode.getHeight());
    }

    public static void main(String args[]) {
        new TestFrame().setVisible(true);
    }
}

So I can't use the default graphics config, that was the problem. Thanks. — dutt, Sep 14 '15 at 09:03

Get current display size in Java

1 Answers1