All Questions

886
votes
63answers
658389 views

What does this mean? "'NSUnknownKeyException', reason: … this class is not key value coding-compliant for the key X"

I'm trying to link a UILabel with an IBOutlet created in my class. My application is crashing with the following error. What does this mean? How can I fix it? *** Terminating app due to uncaught ...
1174
votes
36answers
388085 views

How to check for an active Internet connection on iOS or OSX?

I would like to check to see if I have an Internet connection on iOS using the Cocoa Touch libraries or on OSX using the Cocoa libraries. I came up with a way to do this using an NSURL. The way I did...
1126
votes
23answers
425736 views

How do I sort an NSMutableArray with custom objects in it?

What I want to do seems pretty simple, but I can't find any answers on the web. I have an NSMutableArray of objects, and let's say they are 'Person' objects. I want to sort the NSMutableArray by Perso...
714
votes
32answers
227580 views

Can I embed a custom font in an iPhone application?

This question relates to iOS pre-3.2. As of 3.2 this functionality is easily achievable using samvermette's answer below, and I have changed the Accepted Answer (from commanda to samvermette) to refle...
181
votes
9answers
125579 views

How to get pixel data from a UIImage (Cocoa Touch) or CGImage (Core Graphics)?

I have a UIImage (Cocoa Touch). From that, I'm happy to get a CGImage or anything else you'd like that's available. I'd like to write this function: - (int)getRGBAFromImage:(UIImage *)image atX:(int)...
305
votes
3answers
116026 views

How do I associate file types with an iPhone application?

On the subject of associating your iPhone app with file types. In this informative question I learned that apps could be associated with custom URL protocols. That was almost one year ago and since...
155
votes
9answers
48443 views

How does an underscore in front of a variable in a cocoa objective-c class work?

I've seen in a few iPhone examples that attributes have used an underscore _ in front of the variable. Does anyone know what this means? Or how it works? An interface file I'm using looks like: @int...
684
votes
16answers
162615 views

@class vs. #import

It is to my understanding that one should use a forward-class declaration in the event ClassA needs to include a ClassB header, and ClassB needs to include a ClassA header to avoid any circular inclus...
438
votes
35answers
308998 views

How do I size a UITextView to its content?

Is there a good way to adjust the size of a UITextView to conform to its content? Say for instance I have a UITextView that contains one line of text: "Hello world" I then add another line of text:...
481
votes
19answers
266755 views

How to programmatically send SMS on the iPhone?

Does anybody know if it's possible, and how, to programmatically send a SMS from the iPhone, with the official SDK / Cocoa Touch?

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