Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!npeer01.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail From: Lew Newsgroups: comp.lang.java.programmer Subject: Re: I need a different approach - suggestions please Date: Wed, 27 Jun 2012 18:54:21 -0700 (PDT) Organization: http://groups.google.com Lines: 84 Message-ID: References: NNTP-Posting-Host: 69.28.149.29 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: posting.google.com 1340848462 4868 127.0.0.1 (28 Jun 2012 01:54:22 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Thu, 28 Jun 2012 01:54:22 +0000 (UTC) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=69.28.149.29; posting-account=CP-lKQoAAAAGtB5diOuGlDQk0jIwmH0T User-Agent: G2/1.0 X-Received-Bytes: 4415 Xref: csiph.com comp.lang.java.programmer:15696 bilsch wrote: > Lew wrote: >> There are a few mistakes in your code. >> >> You don't need to call 'super()' in the constructor explicitly. >> That's what happens by default anyway. >> >> You called the constructor directly from the 'main()' routine. That means >> you called it from the primary thread of the program. You don't know this >> yet, probably, unless you've already studied concurrency in Java a little bit. >> >> The problem is that the GUI won't work right if you do that. You have to >> move GUI actions onto the "Event Dispatch Thread" (EDT), a background >> thread that the system creates to handle all GUI actions. >> >> Also, you start all the action from the constructor. That's bad. As its name >> implies, a constructor's purpose is to _construct_ an object, not run its logic. >> Run the logic after construction completes and the instance is no longer in a >> partially-built state. >> >> And make your indentation consistent with the Java coding conventions (available >> on line). >> >> So all together, you'd do something like: >> >> public static void main(String[] arguments) { >> java.awt.EventQueue.invokeAndWait( new Runnable() { >> @Override public void run() { >> CalcGUIQ1 calculator = new CalcGUIQ1(); >> calculator.setVisible(true); >> } >> }); >> } > > With help I've gotten some errors out of the program but I have reached > a point where something just won't work how it should. Your comments What doesn't work, and how should it? > here lead me to believe the reason is the basic way I have things laid > out. But I don't know how to: > > > move GUI actions onto the "Event Dispatch Thread" (EDT), further I > dont know how to write an EDT, or what specifically are 'GUI actions' as > opposed to other lines that relate to the GUI. You don't write the EDT. Did you read the tutorial link I provided? GUI actions are all things that happen on the GUI, such as creating a 'JFrame', calling 'pack()', playing with 'Graphics', or anything else that is part of the GUI. Non-GUI actions are things like writing files, calculating values, updating the logical model, or anything else that is not part of the GUI. Do please read the tutorial to which I linked. There's a reason I provided that link. > Also, I thought the stuff I have in the constructor belonged there. Not all of it. The program itself must run from a *completely* constructed object. You start the program from inside the constructor, therefore it is running on an *incompletely* constructed object. > I dont know where to call the constructor from if not from 'main'. You should call the constructor from 'main()', provided you properly guard it inside the 'invokeAndWait()' call. Why did you think I recommended otherwise? > I did some reading about threads being unsafe. > > It would be very helpful to me if you could show how to rearrange the > code like you say would be better. If you have the time, it would be > very helpful. Thanks. What was wrong with what I already showed you (and you quoted)? -- Lew