haferblues haferblues -4 years ago 60
Java Question

Application turns black when dragged from a 4k monitor to a FullHD monitor

My notebook has a 4k display. My external monitor is 1920. When I drag my Java Swing app window from the 4k display onto the external monitor it gets completely black except for the window frame. It doesn't matter whether I maximize it on the external monitor or not.

Here is the

HelloWorldSwing
example I got from Oracle.com. It shows the exact same behaviour.

import javax.swing.*;

public class HelloWorldSwing {
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("HelloWorldSwing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Add the ubiquitous "Hello World" label.
JLabel label = new JLabel("Hello World");
frame.getContentPane().add(label);

//Display the window.
frame.pack();
frame.setVisible(true);
}

public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}


It looks like a bug in Swing. Anyway, I have to find a solution/work-around. Any ideas?

I'm running jdk/jre 1.8.0 121.

Answer Source

I found a solution. Basically I added a component listener to my main frame and listen on move events. Whenever the frame is moved I check on which display it is located. As soon as the frame has been moved to another display I set it invisible, then set new bounds located on the "new" display, set the extended state to maximized and finally make the frame visible again.

For the last minutes I wildly dragged windows from one display to another all while jumping for joy. If you also want that much fun in your life, here is the code:

mainFrame.addComponentListener(new ComponentListener()
    {
        @Override
        public void componentMoved(ComponentEvent evt)
        {
            GraphicsConfiguration conf = mainFrame.getGraphicsConfiguration();
            GraphicsDevice curDisplay = conf.getDevice();
            GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();

            GraphicsDevice[] allDisplays = env.getScreenDevices();
            for (int i = 0; i < allDisplays.length; i++)
            {
                if (allDisplays[i].equals(curDisplay))
                {
                    //the window has been dragged to another display
                    if (i != _currentDisplayIndex)
                    {
                        final Rectangle sb = conf.getBounds();

                        mainFrame.setVisible(false);
                        //it is important to set the bounds somewhere on the new display before setting the extended state to maximized
                        mainFrame.setBounds(sb.x, sb.y, 1000, 800);
                        mainFrame.setExtendedState(Frame.MAXIMIZED_BOTH);
                        mainFrame.setVisible(true);

                        _currentDisplayIndex = i;
                    }
                }
            }

        }

        @Override
        public void componentShown(ComponentEvent evt)
        {
        }

        @Override
        public void componentResized(ComponentEvent evt)
        {
        }

        @Override
        public void componentHidden(ComponentEvent evt)
        {
        }
    });

Yippie!

Side note: I tried to take a screenshot of the black window earlier. However, the screenshot isn't black, but just normally shows all swing components. That makes me believe, that it is not only a swing issue, but also some sort of a windows/display driver issue. Pressing "printscreen" doesn't trigger anything in java (I guess), but only refreshes the display.

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