Question

I am having a simple problem I guess, that u should know how to solve..
I am trying to do this:
I have a JFrame.
Then I create a JPanel and set his layout to GridLayout(5,5)
Finnaly I add this JPanel to the Container of my JFrame.

When I try to get the width of my panel it shouldnt give me 0 right?
I do this: System.out.println(mypanel.getSize().getWidth()); and it says that is zero :c
why ??
I wanna know the size so I can divide per 5 and know how much to paint for each label, this will be a grid of labels..
Thanks alot in advance…

    public janela(){

    window = new JFrame("teste");
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setSize(300,300);
    contentor = window.getContentPane();
    interior = new JPanel();
    interior.setLayout(new GridLayout(5,5));
    contentor.add(interior);

    System.out.println(interior.getSize().getWidth());   //it says 0 ?!?! why??
     }

thanks alot in advance guys!!!!

Answer 1

Panels are sized based on their layout. specifically when they are shown and doLayout() is called for you. doLayout() figures out what the appropriate size for your panel is based on the contents of the panel, and the layout manager in force. Since your panel has nothing in it, the appropriate size is 0, 0.

If you will never have anything in the panel, and want to circumvent this (0, 0) size, you can override getPreferredSize() of the panel to return a size that you want the panel to respect for layout.