Top "Objective-c" questions

This tag should be used only on questions that are about Objective-C features or depend on code in the language.

Error message '_BSMachError: (os/kern) invalid capability (20)'

Please note that this error message is pretty low level, so it crops up for different reasons in different scenarios. …

ios objective-c xcode7
What is the AppDelegate for and how do I know when to use it?

I'm just beginning to work on iPhone apps. How do I know when I should be putting stuff in AppDelegate …

ios objective-c cocoa-touch
HTML character decoding in Objective-C / Cocoa Touch

First of all, I found this: Objective C HTML escape/unescape, but it doesn't work for me. My encoded characters (…

iphone html objective-c cocoa cocoa-touch
Can I set the `attributedText` property of `UILabel`

Can I set the attributedText property of a UILabel object? I tried the below code: UILabel *label = [[UILabel alloc] init]; …

ios objective-c nsattributedstring
How do I set a UInt32 to it's maximum value

What is the maximum value for a UInt32? Is there a way I can use the sizeof operator to get …

ios objective-c uint32
Getting an object from an NSSet

If you can't get an object with objectAtIndex: from an NSSet then how do you retrieve objects?

objective-c cocoa cocoa-touch object nsset
Convert NSData bytes to NSString?

I'm trying to use the BEncoding ObjC class to decode a .torrent file. NSData *rawdata = [NSData dataWithContentsOfFile:@"/path/to/the.…

objective-c cocoa bittorrent
NULL vs nil in Objective-C

In observeValueForKeyPath:ofObject:change:context: - why do the docs use NULL instead of nil when not specifying a context …

objective-c cocoa null
Using `textField:shouldChangeCharactersInRange:`, how do I get the text including the current typed character?

I'm using the code below to try and have textField2's text content get updated to match textField1's whenever …

ios objective-c uitextfield
Access Container View Controller from Parent iOS

in iOS6 I noticed the new Container View but am not quite sure how to access it's controller from the …

ios objective-c swift uiviewcontroller uicontainerview