Top "Cocoa" questions

Cocoa is Apple's application-development framework for macOS, consisting of Foundation, Application Kit, and Core Data.

Xcode - How to fix 'NSUnknownKeyException', reason: … this class is not key value coding-compliant for the key X" error?

I'm trying to link a UILabel with an IBOutlet created in my class. My application is crashing with the following …

ios macos cocoa cocoa-touch interface-builder
How do I use NSTimer?

How do I use an NSTimer? Can anyone give me step by step instructions?

objective-c cocoa nstimer
How to check for an active Internet connection on iOS or macOS?

I would like to check to see if I have an Internet connection on iOS using the Cocoa Touch libraries …

ios macos cocoa cocoa-touch reachability
Constants in Objective-C

I'm developing a Cocoa application, and I'm using constant NSStrings as ways to store key names for my preferences. I …

ios objective-c cocoa nsstring constants
Xcode build failure "Undefined symbols for architecture x86_64"

An Xcode beginner's question: It is my first experience with Xcode 4.6.3. I am trying to write a very simple console …

objective-c xcode macos cocoa iobluetooth
How do I create delegates in Objective-C?

I know how delegates work, and I know how I can use them. But how do I create them?

ios objective-c cocoa callback delegates
How do I iterate over an NSArray?

I'm looking for the standard idiom to iterate over an NSArray. My code needs to be suitable for OS X 10.4+.

objective-c cocoa iteration nsarray enumeration
Formatting NSDate into particular styles for both year, month, day, and hour, minute, seconds

I basically need to get current date and time separately, formatted as: 2009-04-26 11:06:54 The code below, from another question …

cocoa cocoa-touch nsdate nsdateformatter date-formatting
Hidden Features of Xcode

With a huge influx of newbies to Xcode, I'm sure there are lots of Xcode tips and tricks to be …

objective-c xcode macos cocoa
Cocoa Autolayout: content hugging vs content compression resistance priority

I can't find a clear answer on Apple documentation regarding Cocoa Autolayout about the difference between content hugging and compression …

cocoa autolayout