How to set JFrame to appear centered, regardless of monitor resolution?

Question

While working with Java, I find it hard to position my main window in the center of the screen when I start the application.

Is there any way I can do that? It doesn't have to be vertically centered, horizontal alignment is the more important goal for me. But vertical alignment is also welcome.

Answer 1

Use setLocationRelativeTo(null)

This method has a special effect when you pass it a null. According to the Javadoc:

If the component is null, or the GraphicsConfiguration associated with this component is null, the window is placed in the center of the screen.

This should be done after setting the size or calling pack(), but before setting it visible, like this:

frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);

Answer 2

I always did it in this way:

Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
this.setLocation(dim.width/2-this.getSize().width/2, dim.height/2-this.getSize().height/2);

where this is the JFrame involved.

Answer 3

You can call JFrame.setLocationRelativeTo(null) to center the window. Make sure to put this before JFrame.setVisible(true)

Answer 4

Just click on form and go to JFrame properties, then Code tab and check Generate Center.

Answer 5

As simple as this...

setSize(220, 400);
setLocationRelativeTo(null);  

or if you are using a frame then set the frame to

frame.setSize(220, 400);
frame.setLocationRelativeTo(null);  

For clarification, from the docs:

If the component is null, or the GraphicsConfiguration associated with this component is null, the window is placed in the center of the screen.

Answer 6

i am using NetBeans IDE 7.2.1 as my developer environmental and there you have an option to configure the JForm properties.

in the JForm Properties go to the 'Code' tab and configure the 'Generate Center'. you will need first to set the Form Size Policy to 'Generate Resize Code'.

Answer 7

I am using NetBeans IDE 7.3 and this is how I go about centralizing my JFrame Make sure you click on the JFrame Panel and go to your JFrame property bar,click on the Code bar and select Generate Center check box.

Answer 8

If you use NetBeans, simply click on the frame on the design view, then the code tab on its properties. Next, check 'Generate Center'. That will get the job done.

Answer 9

If you explicitly setPreferredSize(new Dimension(X, Y)); then it is better to use:

setLocation(dim.width/2-this.getPreferredSize().width/2, dim.height/2-this.getPreferredSize().height/2);

Answer 10

In Net Beans GUI - go to jframe (right click on jFrame in Navigator) properties, under code, form size policy property select Generate Resize Code. In the same window, Untick Generate Position and tick Generate Size and Center.

Enjoy programming. Ramana

Answer 11

You can use this method, which allows the JFrame to be centered and full screen at the same time.

yourframe.setExtendedState(JFrame.MAXIMIZED_BOTH);

Answer 12

I will provide 3 methods to your question :

You can either use the simplest method to center it, relative to your viewport, which is :

setLocationRelativeTo(null);

The second one, is to use :

Dimension dim = Toolkit.getDefaultToolkit().getScreenSize(); frame.setLocation(dim.width/2 - frame.getSize().width/2, dim.height/2 - frame.getSize().height/2);

And the third one, the most customizable one, is a bit more complicated, but is the most useful. (in my opinion) :

1.) You create a JButton and add it to your panel.

2.) You add an ActionListener event to it.

3.) On your button click, you invoke the method :

frame.getLocationOnScreen(); which you need to save to a Point variable => Point location = frame.getLocationOnScreen;

4.) After that, you invoke : System.out.println(location);, so that you can get the location on the screen that you want to put your frame to - it will print it to the console.

5.) You delete the button and ActionListener, after you've got the x, y coordinates.

6.) You invoke : frame.setLocation(x, y);

• That's it.

The code looks like this :

JButton button = new JButton();
    button.setText("Get Location");
    panel.add(button);
    
    ActionListener onButton = new ActionListener() {
        
        @Override
        public void actionPerformed(ActionEvent e) {
            
            Point location = frame.getLocationOnScreen();
            System.out.println(location);
            
        }
        
    };
    
    button.addActionListener(onButton);

After you have the location, do this :

frame.setLocation(445, 195);

• Hope I was helpful. ^