Using null Layout - Problems

Question

Hullo - I've written a little app that, because of the nature of what it does, prettymuch requires the use of null layout. It works well enough, but there are a few points where it does strange things that I don't understand. I haven't been able to find any good docs anywhere for how exactly layout/rendering works. The Swing tutorial, for example, almost completely ignores the topic.
Basically, I set the layout to null, add my components, use setBounds...but then nothing happens. In order for anything to be visible, I have to call pack() before I call show(). What is pack? What does it do? How can Sun's null layout examples work even though most of them don't use it?
Second, if I create JFrame of a certain size, and add a component that goes off the bottom of the JFrame (on purpose), then expand the size of the JFrame to reveal the bottom part of that component, it doesn't paint - there's just a grey area. No amount of repaint() pack() or anything will cause it to show. The only way I've found to do it is to make the JFrame larger to begin with, add the component so that it's visible, then resize to the smaller size, which is kind of ugly and clunky.
I basically do not understand why Swing is doing the things it does; why it paints sometimes and not other times, where it paints, when it paints, where it shows objects, how it packs them, etc. I would be very grateful if someone could englighten me!

Answer 1

Hullo - I've written a little app that, because of the
nature of what it does, prettymuch requires the use of
null layout. It works well enough, but there are a
few points where it does strange things that I don't
understand. I haven't been able to find any good docs
anywhere for how exactly layout/rendering works. The
Swing tutorial, for example, almost completely ignores
the topic.
Basically, I set the layout to null, add my
components, use setBounds...but then nothing happens.
In order for anything to be visible, I have to call
pack() before I call show(). What is pack? What
does it do? How can Sun's null layout examples work
even though most of them don't use it?
Second, if I create JFrame of a certain size, and add
a component that goes off the bottom of the JFrame (on
purpose), then expand the size of the JFrame to reveal
the bottom part of that component, it doesn't paint -
there's just a grey area. No amount of repaint()
pack() or anything will cause it to show. The only
way I've found to do it is to make the JFrame larger
to begin with, add the component so that it's visible,
then resize to the smaller size, which is kind of ugly
and clunky.
I basically do not understand why Swing is doing the
things it does; why it paints sometimes and not other
times, where it paints, when it paints, where it shows
objects, how it packs them, etc. I would be very
grateful if someone could englighten me!Okay, I think you should call setVisible(true); instead of pack then show. Pack basically organizes the components so they take up the least amount of room, and then it shrinks the frame to as small as it will go without hiding any components. It think if you call revalidate() instead of repaint(), should solve your problem.
The other thing to do, is (hehe) make your own components