问题
I know the fact that when I create an instance of a JComponent, it has it's own preferred size. Now let's suppose that I setPreferredSize that JComponent manually with a dimension of 0 x 0. And i want that Component to "reset" its own preferredSize. How do I do that?
回答1:
1) Setting preferred size to null should reset the component back to getting its preferred size calculated as if it was never set.
component.setPreferredSize(null);
This might not do what you want, depending on how you signal that the layout should be redone - but at least it is technically the answer to your question.
2) It is generally advised to not use setPreferredSize, see this post
来源：https://stackoverflow.com/questions/8815401/how-do-i-recalculate-preferred-size-of-a-jcomponent