Can someone explain why...

[Krooger]

When I use this code:

leftPanel.setBackground(new Color(200));
leftPanel.setSize(new Dimension(300,300));
mainPanel.add(leftPanel);

This panel will be added to my main Panel but it will be a little square and not the size I set it to whereas when I use this code:

leftPanel.setBackground(new Color(200));
leftPanel.setPreferredSize(new Dimension(300,300));
mainPanel.add(leftPanel);

It works exactly as I want it to, and it is a large square with given dimensions.

Why is it that setSize does not make this panel larger?

Also when I use this code

tableFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
tableFrame.setExtendedState(Frame.MAXIMIZED_BOTH);	
tableFrame.setUndecorated(true);

System.out.println(tableFrame.getBounds().getHeight()+"--"+tableFrame.getWidth());

It will tell me that the size of my Frame is 0,0 even though it is coving my whole screen. How would I get the current height and width in this case?


Thank You

[zweibieren]

setSize() is useless. It is to be called by a LayoutManager,
but LayoutMangers generally call setBounds().
The methods to set the Preferred, Minimum, and Maximum sizes
store the values and send them to the LayoutManager when it asks.

The Frame sizes are not set until pack() or validate() is called.