Steve McLeod Steve McLeod - 5 months ago 44
Java Question

How do I determine which monitor a Swing mouse event occurs in?

I have a Java MouseListener on a component to detect mouse presses. How can I tell which monitor the mouse press occurred in?

public void mousePressed(MouseEvent e) {
// I want to make something happen on the monitor the user clicked in

The effect I'm trying to achieve is: when the user presses the mouse button in my app, a popup window shows some info, until the mouse is released. I want to ensure this window is positioned where the user clicks, but I need to adjust the window position on the current screen so that the entire window is visible.

Answer Source

You can get display information from java.awt.GraphicsEnvironment. You can use this to get a information about your local system. Including the bounds of each monitor.

Point point = event.getPoint();

GraphicsEnvironment e 
     = GraphicsEnvironment.getLocalGraphicsEnvironment();

GraphicsDevice[] devices = e.getScreenDevices();

Rectangle displayBounds = null;

//now get the configurations for each device
for (GraphicsDevice device: devices) { 

    GraphicsConfiguration[] configurations =
    for (GraphicsConfiguration config: configurations) {
        Rectangle gcBounds = config.getBounds();

        if(gcBounds.contains(point)) {
            displayBounds = gcBounds;

if(displayBounds == null) {
    //not found, get the bounds for the default display
    GraphicsDevice device = e.getDefaultScreenDevice();

    displayBounds =device.getDefaultConfiguration().getBounds();
//do something with the bounds
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