How to get real JPanel Size?

Question

How should I get real JPanel size in JFrame?

Solution 1

The size will be 0,0 until it is displayed because the components and layout are not calculated beforehand.

Solution 2

thePanel.getSize();

This returns the Dimension.

I sometimes add a ComponentListener to show the dimension when the panel is resized.

EDIT: If you want the size of the content pane of the JFrame then

theFrame.getContentPane().getSize();

Comments

[Andrew Thompson]

"By really calling getSize()." It is possible that the method is being called prior to when it becomes realized. For more specific advice, post an SSCCE.

[km1]

As @Andrew says. But you can't do it until its been rendered.

[Yoda]

It does not give real size java.awt.Dimension[width=0,height=0] I used that before

[MadProgrammer]

@RobertKilar km half answered you question, add a ComponentLsterner to the panel you're interested in & monitor the componentResized event

[km1]

@RobertKilar you're probably getting the size before its rendered. Try the component listener's resize event handler.

[Sakkeer Hussain]

Is there any call back for initialising child components of jPanel after it got its real width and height?

[Cardinal System]

Is there a way to force the layout to calculate component locations and sizes without calling setVisible(true)?

[Cardinal System]

@SakkeerHussain if you queue a runnable with SwingUtilities#invokeLater(java.lang.Runnable) after calling setVisible(true) on your JFrame, then that runnable will be executed after the panel is assigned its size. With this method, however, you will have to initialize your panel beforehand and update it after it's actually visible.