[MacRuby-devel] Problem with a window controller

[Robert Carl Rice]

Hi David and Jean-Denis,

I haven't been following the list for a while so I'm just catching up and see my message about initialization sparked some responses.

I haven't observed the behavior that you mention of "awakeFromNib" being called more than once for an object instantiated by NIB file expansion and I log calls to "awakeFromNib" in my applications, but I haven't used the "initWithCoder" method yet either. I think all all MacRuby subclass objects are "custom" objects and will receive an "init" message in addition to or in lieu of "initWithCoder".

I should give "initWithCoder" a try to reduce my app startup time. I load some data from CSV files and the Ruby CSV file parser is so incredibly slow that I have to parse the files one line at a time in an NSTimer loop to avoid getting the "waiting" icon and crashing my USB device drivers. A large CSV file of about 2,000 lines takes 20-30 seconds of processing time to load! I probably should pre-parse the CSV files then load the data from binary files.

Do you know what would cause "awakeFromNib" to be called more than once for an object instance? I have considered "awakeFromNib" to be an initialization method and I've been using it as such without a problem.

My understanding is that the NIB file expansion instantiates objects by unarchiving but then uses your attr_writer or attr_accessor construction methods to set up outlet connections and it calls setTarget and setAction methods to establish action connections before calling "awakeFromNib".

Bob Rice

On Dec 10, 2012, at 5:38 AM, david kramf <dakr.012 at gmail.com> wrote:

> Hi Jean-Denis
> 1. Thank you for your advice about awakeFromNib and InitWithCoder.
> 2. "That is a bonus you ..". This is not a bonus. This is Ruby. If you define a Ruby class you expect that any object will get instantiated through "initialize". I have a feeling that all who responded to me on the forum started their programming track from Objective-C and proceeded to Ruby. I am coming from the opposite direction. I come from Ruby and wants to deal with Objective-C as little as possible. So I expect MacRuby to be as much "Ruby" as it is possible.
> Many Thanks, David
> On Dec 10, 2012, at 11:27 AM, Jean-Denis MUYS wrote:
> 
>> 
>> On 7 déc. 2012, at 19:48:39, david kramf <dakr.012 at gmail.com>
>> wrote:
>>> 
>>> Message: 1
>>> Date: Fri, 7 Dec 2012 19:48:39 +0200
>>> From: david kramf <dakr.012 at gmail.com>
>>> To: "MacRuby development discussions."
>>> 	<macruby-devel at lists.macosforge.org>
>>> Subject: Re: [MacRuby-devel] Problem with a window controller
>>> Message-ID: <1F1681C7-9DE6-4971-8D17-722F5EC630CA at gmail.com>
>>> Content-Type: text/plain; charset="us-ascii"
>>> 
>>> Hi Bob,
>>> "As you become more familiar with IB, you will probably do more initialization of objects in IB and less in MacRuby. Nib file expansion instantiates objects and then makes calls to initialize the objects using the same methods that you are using to initialize objects in MacRuby. Actually, in a large application, it would difficult to hook up all of the outlets without using IB."
>>> 
>>> From my modest acquaintance with MacRuby that is not exactly the case since when the NIB instantiates  an NSWindowController object , it does not call "initialize"
>> 
>> Cocoa, whether accessed from Ruby, Python, Objective-C or any language, uses the Cocoa initialization patterns. It's unrealistic to assume the framework patterns to change when you change the client language.
>> 
>>> ,as defined in Ruby , but calls "awakeFromNib".
>> 
>> It does, but caveat: awakeFromNib is *not* an initialization method, even though it is often used as such. I was bitten before. The correct initialization method to use for Nib files is initWithCoder:. What's the difference, says you (and me)? Behold:  awakeFromNib can be called several times in the lifetime of an object. This is no big deals for most initializations, but becomes a major issue in others. In my case, I was registering for notifications in awakeFromNib. Since I was registered several times, I got the notifications multiple times, and since I only unsubscribed once in dealloc, my app would crash.
>> 
>> Many cases when awakeFromNib is called more than once are programming errors, but not all. And since there *is* a real initializer, I recommend using it.
>> 
>> So in that case why is there an awakeFromNib method at all? It is because at initWithCoder: time, IB outlets are not yet loaded and are all nil. So awakeFromNib is meant to for initialization code that configures outlet.
>> 
>> So here is a recipe:
>> 
>> 1- Does you initialization code requires IB outlets to be alive? If not, override initWithCoder:
>> 2- If so, put it in awakeFromNib
>> 3- Does that awakeFromNib initialization code need to be called once only? if so, make it conditional on it having been already be called.
>> 4- Optional: assert that awakeFromNib was not called before, and if that assert fires, investigate whether the case is legitimate or due to a bug in your code.
>> 
>>> Only when you instantiate your controller from the code itself , you get your "initialize"method called.  
>> 
>> That is a bonus you just can be happy to have due to the deep integration of MacRuby in the Objective-C runtime system. There is no reason to assume that bonus to expand to objects created by the framework.
>> 
>>> I know I still have a lot of practicing on IB. What I find disturbing ,is that when I do something  with IB I cannot see the code created to accommodate my actions ( maybe because I only work in MacRuby and not Objective-C?).
>> 
>> No. This is simply because there **no code created**. At all. IB does't generate code. And lest I forget: Interface Builder is not a code generation tool. IB instantiates and populates objects, and then serializes them to disk. Those objects are then simply deserialized from disk in your app. At no point ever is any code generated. Therefore, there is no "code created to accommodate your actions" for you to see. Even in Objective-C.
>> 
>> Best regards,
>> 
>> Jean-Denis
>> 
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