Chapter 4: windowBasedApp example - Doesn't work?

thepianoguy · May 18th, 2011, 12:25 AM

If you can't work out the problem, send your project to
[email protected]
and I will take a look at it for you.

Previous versions of Xcode auto-completed the file name forward declaration after @class, as of now Xcode 4 does not. Hopefully that will be remedied in the future.

Bob

tleveque · May 18th, 2011, 09:23 AM

Quote:

Originally Posted by thepianoguy

If you can't work out the problem, send your project to
[email protected]
and I will take a look at it for you.

Previous versions of Xcode auto-completed the file name forward declaration after @class, as of now Xcode 4 does not. Hopefully that will be remedied in the future.

Bob

Thank you for your proposition. Before I will try again to solve it by myself. Another 24 hours and I give-up!

By the way, looking at the dowloaded source code, I find out that there is nothing in the Nib field of the MainWindow's HelloWorldViewController.
I then remove it from my project and suddenly the autocomplete for the @class is working!!!
But the application still show the empty screen...

lukasbradley · May 18th, 2011, 09:28 AM

I don't know if this will possibly help or not, but I literally deleted and recreated the entire project to get it to work. Very frustrating.

Best of luck.

tleveque · May 18th, 2011, 09:30 AM

Quote:

Originally Posted by lukasbradley

I don't know if this will possibly help or not, but I literally deleted and recreated the entire project to get it to work. Very frustrating.

Best of luck.

I already did that twice... No success. Maybe a clean is needed before recompiling and running? I will try that tonight...

tleveque · May 18th, 2011, 08:56 PM

Quote:

Originally Posted by tleveque

I am also unable to make it work!

I did it twice with the same result.
And yes I did a save after each edition of .xib files...

I started suspecting something is not going well at step 9, when they ask to select HelloWorldViewController as NIB name. For me, the drop down list was empty!
So I typed it manually.

I also supposed XCode should be able to autocomplete the class name after the @class. I am right? If yes, there is no HelloWorldViewController in my autocompletion list...

I double and even tripple check all my code and it still does not work.
No compilation errors or any warning. The iPhone Simulator just show a blank screen....

I am using XCode 4. But it should not make any difference I think.

Any idea someone?

I solved my problem!!!
The fault is on Xcode 4!
When Xcode create the windowBasedAppAppDelegate.m file, the synthesize for window property is created like this:

Code:

@synthesize window=_window;

Instead of just:

Code:

@synthesize window;

And of course, in my didFinishLaunchingWithOptions method I used:

Code:

[window addSubview:viewController.view];

I didn't use _window.

Removing the =_window and the '_' in the dealloc method solved the problem.

Now, can anybody explain why is Xcode 4 is doing that?

thepianoguy · May 18th, 2011, 11:15 PM

Xcode is trying to make you use your accessors correctly, and to signify that the window variable is private. You should not remove the underscore. When accessors are used correctly, you minimize potential errors with memory management. Setting the variable directly can cause issues with object ownership. The correct solution (leaving the underscore in) is to replace the book code as follows:

Code:

[self.window addSubview:mySecondViewController.view];

[self.window makeKeyAndVisible];


[self.window release];

Bob

BPearce · May 24th, 2011, 04:31 PM

I had problems with this chapter using XCode 4, as well -- and the first of them was when I created the "HelloWorldViewController" classes, because XCode 4 prompts you to choose a template and then choose a subclass and then give it a name.

It's been some time since I'd last used XCode 3, so I just assumed that the second window was the file naming option, because it seemed familiar (particularly when you don't look closely enough) -- which created a "HelloWorldViewController" superclass (or something) where there shouldn't have been one.

Once I noticed my mistake, and altered some of the "window" code, everything was swell.