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

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 2

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 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

You'll get the size set, after you add this:

frame.setLocationRelativeTo(null);

Answer 8

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 9

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 10

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 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

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 13

For Java Swing:

Go to "Navigator" -> "JFrame" -> "Properties" -> "Code" -> check Generate Center

Answer 14

This worked for me:

Toolkit toolkit = getToolkit();

Dimension size = toolkit.getScreenSize();

setLocation(size.width/2 - getWidth()/2, size.height/2 - getHeight()/2);