Re: Best way to force a JComponent to repaint itself
zerg wrote:
Joshua Cranmer wrote:
You're looking for a method to get a JComponent to repaint. I don't
know about you, but I consider repainting to be a core widget action.
That means I will look first at the root of the widget hierarchy,
which is obviously Component (JComponent is only the root of the
lightweight hierarchy).
You are approaching the search with a detailed knowledge of Swing
internals and design decisions. You are not approaching it from the
perspective of a user of Swing that is more concerned with doing useful
stuff with it than with knowing its in-depth implementation, history,
and so forth.
This is not "detailed knowledge." The Javadocs themselves present this
simple nugget of information: "The Swing classes are built on top of the
AWT architecture."
It is unfortunate that it relies on Component to provide some of its
interface instead of overriding those methods (even with just a call to
super!) still relevant to Swing JComponents so that they appear in the
main listing of JComponent methods.
That makes JComponent unmaintainable, if it has to override all of the
methods, and is bad practice to begin with and possibly destructive to
performance improvements at runtime. Also, by that point, you might as
well not make JComponent inherit from Component.
Inheritance is not done willy-nilly. The fact that JComponent inherits
from Container and Component is important, even if you know nothing
about them. OOP tells you that a JComponent is a Component, and, more
importantly, that JComponent will enhance the capabilities of Component.
Which means that if you can't find something in JComponent, you might
try looking in superclasses.
To give another example, using the DOM. I have a text node. I want to
know what the text inside is. I look on the interface. No method
"getText()". Does that mean that there is no way to do this? No! Its
parent is character data, which has the method "getData()". What if I
want to find which element it is contained in? I have to go back up to
DOM nodes and use the hierarchy information there. In short: if class A
inherits from class B, you'll need to look in both to find useful methods.
This fact, that I was not unsure how to repaint at all but how BEST to
repaint, with what level of wrapping, in a particular situation, seems
to keep getting lost in all of this needless and inexplicable acrimony.
Ever read the Java Tutorials on Sun's website? They cover this sort of
stuff.
The problem isn't even that your perspective differs from mine. It is
that you (collective "you", referring to nearly everyone in this thread
except for me and Daniele) arrogantly presume that anyone whose
perspective differs from yours is defective, ignorant, stupid, or some
such epithet, and take paints to make your opinion clear to the general
public!
Slander and libel will get you nowhere fast. By now, you're resisting a
point several others have made: looking at *only* JComponent for
documentation is not sufficient. What you're arguing is that the
subclass should reimplement all the methods just so that some lazy
person doesn't have to look through a few more pages of documentation,
which is a very, very untenable position.
(Roedy's, a
thinly-disguised promotion of his own web site with little other
content, certainly is not
I would not call it a "thinly-disguised promotion" of his website. I
find that it is an excellent resource for neophytes, especially since it
answers almost all of the basic questions that come up.
The sets of people that they've called rude have a fair degree of
overlap, too, particularly tending to include Andreas, Andrew, Arne,
and Lew.
And, checking the list again, you.
I come on there only because I have a very thick skin and am willing to
point out criticism to those who have little respect to it.
Excuse me? What the heck feudal society did you log in from? Where I
live, we hold various truths to be self-evident, among them that all men
are created equal and have certain inalienable rights.
"... that among these are life, liberty, and the pursuit of happiness,
that to secure these rights, governments are instituted among men,
deriving their just power from the consent of the governed; that
whenever any form of government becomes destructive of these ends, it is
the right of the people to alter or abolish it."
At least quote the whole thing, if you insist on having such an
Amerocentric world view. Also, keep in mind the actual intent of that
text there.
As far as I am concerned, there are no "tiers" here, with some king or
It's not a feudal tier, it's a tier in terms of posters. I was pointing
out that you're more likely to find a posting by Lew than you are to
find one by yourself here. It was not in any form meant to imply a
hierarchy of control or responsibility, etc.
For comparison, I would place myself no higher than the third tier
EVER so humble, arencha?
No, I just don't post terribly often, only once or twice a day at most.
Posters of... controversy probably get more, though (think XahLee,
Twisted, or JSH).
Dissension should be tolerated in a free and just society. One would
hope that an unmoderated newsgroup would be a paragon of such, lacking
as it does anyone with actual authority backed by actual ability to
forcibly impose his will upon others. But oh, no ...
And another case where you've missed the point. XahLee X-posted rather
off-topic messages across several disparate newsgroups, Twisted
embroiled the newsgroup into a rather idealistic view of economics and
related topics, and JSH resisted rather strongly the idea that his
algorithms were incorrect. Many here would consider these three posters
to all be trolls (a moniker that is undeserved in JSH's case, IMO), and
I was trying to be polite in referring to them.
Sure dissension should be tolerated, but this is a forum for discussing
Java, not discussing the flaws in patent law.
--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth