如何设置JPanel大小？

Question

I'm using Netbean's form creator and I'm trying out some things. I'm not sure if it's the layout manager, but when I create my own JPanel and add it to the main content pane of the my window, the size of the panel always maximizes inside the FrameView no matter what re-dimensioning methodology I use such as setSize or setPreferred size. I'm very new to AWT and Swing.

Answer 1

With NetBeans WYSIWYG designer it's a peace of cake - just be sure to use Free Form Design and use mouse for resizing. Maybe the panel is itself larger than FrameView, so double click on it (you are editing it exclusively) and make it smaller. Than double click to get back to parent component and you should be fine.

Or maybe check some tutorials at NetBeans site .

Answer 2

You're not supposed to set sizes manually. Leave that to the layout managers, and your GUI will not break when the window size or the font or even just a button label changes.

The trick with layout managers is that you can use not just one but several, in nested JPanel s. That way, nearly any layout is possible.

Answer 3

This happens because the layout manager of JPanel's container (perhaps it is either JFrame or another JPanel) instructs the JPanel to maximize.

Do the following:

1. Find out, who is the parent of this JPanel (take a look at NetBeans's containment object tree)

2. Check, what layout is defined for the container

3. Read the documentation about LayoutManager's (they're in java.awt package)

4. ???

5. PROFIT!

Answer 4

In my experience, Swing is a very picky thing. I'd try setMaximumSize and setPreferedSize . As a side note though: when ever I used GridLayout , it always stretches whatever is in each of the cells (to make it symmetrical I guess). Flow, Box, Border, and I think GridBag don't have that problem though.

-Brett