Objective-c is a highly dynamic message-based object-oriented language, superset of C, that is a primarily used for programming Apple's Mac OS X and iOS platforms.

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When should one use “out” parameters?

In Objective-C, there are several methods like initWithContentsOfFile:encoding:error: where one passes in a reference to an NSError object for the error: parameter. In this example, the value of the ...
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Create an Objective-C category to route methods depending on a specified type

For one project, I needed to find a solution to avoid code like this: if ([self.desiredColor isEqualToString:@"Red"]) [self constructRedMenu]; else if ([self.desiredColor ...
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Objective-C message passing related queries

I am learning objective-C after having good knowledge of C/C++. I have 2 questions: Are Obj-C message passing and C++ vtable, two different ways of implementing polymorphism or Are they two very ...
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What guidelines do you suggest for using Objective-C Properties?

Objective-C 2.0 introduced properties. While I personally think properties are nice addition to the language, I have seen a trend of making every instance variable as a property. Apple sample codes ...
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Preventing override of methods in Objective-C [closed]

Objective-C lacks private methods or java-esque final methods. This means that it is possible for a subclass to (accidentally) override some of the internals of a superclass. How does one prevent ...
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Which design pattern to choose when supporting multiple analytic tools?

I have spent quite some time learning all possible design patterns but I cannot find the ideal one for the following case. I am developing an iOS app where we are using multiple analytics tools like ...
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81 views

Swift: Creating an empty array [closed]

The following: var emptyArray = [String](); What do I need the parentheses () for? [String] says, that the array accepts strings only. But why do I have to put the () there?
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Why can't I use an operator like plus sign to concatenate strings? [closed]

Why in Objective-C we should be typing explicit references to methods like stringByAppendingString to concatenate strings, when in some other languages we can use operators for that? For example, ...
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374 views

How can I create a software patcher for OS X?

I'm building some software for OS X that isn't distributed through the Mac App Store. My software allows users to download different modules uploaded by various people too. How can I create a ...
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How static functions are better than Class Methods in Objective-C [closed]

I was going to through this post by Mattt Thompson in which he mentions that Static functions are nicer than shoe-horned class methods I just don't see any flaw with Class methods in ...
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Does variable type specification lead to any performance difference?

Let's say I have a very long method which basically creates a responsive and resizable layout for a user interface by using a few fixed values and a few variable ones taken from an element's ...
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402 views

How does Telnet work?

Is telnet just a simple socket connection? I usually have a difficult time in the networking area so I use some code from the internet to help me out, but I can't seem to find a library for Telnet in ...
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284 views

In objective C, where does the inheritance chain end? [closed]

In objective C, classes are objects, but what object owns the class objects? I am trying to get as detailed an understanding of iOS programming as I can, and this question popped into my head, so I ...
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Is it acceptable to use C11 generic macros in Objective-C to box numbers?

I was getting tired of repeating types when writing things like this: NSDictionary* d = @{@"so": [NSNumber numberWithInt:index]), @"much": [NSNumber numberWithBool:accepted]), ...
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1answer
179 views

Macro guard in Objective-C

I have noticed that many famous libraries written in Objective-C (eg. AFNetworking) use the macro guard inside their header files. Im aware that the #import directive, which works exactly like ...
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1answer
110 views

Drawbacks to redefining method in precompiled header

I have a lot of calls to NSLog(...). I need to change all of these calls to CLSNSLog(...). So I added this to my precompiled header (.pch): #import <CrashlyticsFramework/Crashlytics.h> #define ...
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Program Structure for Table Cells Representing Objects

So I have a program with "cue" objects and each have their own table cell. The thing is that the table cells have loading bars on them that represent the progress of the cues. This presents the ...
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1answer
398 views

Approach to managing multiple services like Evernote, Google drive, dropbox in iOS

I'm trying to think up a scenario when I'd have three different forms of NSData (or whatever) to be sent to three different services like Evernote, Google drive, Dropbox. Granted, each of those has ...
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227 views

How to remove redundant code that enables button. Or “if” statement

I got probably "micro optimization" problem. I got "History number", "Next Number", "Reset" buttons, as well "label" for text. Every time I click At "Next number" button I would like to show random ...
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1answer
625 views

Apple Dispatch Queue vs Threads

I've heard a lot about apple's famous dispatch queues and the GCD but today was the first time I decided to understand exactly what is going on, so I started reading Concurrency Programming Guide and ...
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1answer
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Pictures from iPhone to clients FTP server - Directly (iPhone->FTP) or Cloud (iPhone->Amazon->FTP)

My clients wants to take pictures with their iPhone's and place them collectible on their server, suggested by FTP. I can see there is two solutions: Directly upload from the iPhone to the FTP ...
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1answer
129 views

Go/Obj-C style interfaces with ability to extend compiled objects after initial release

I have a conceptual model for an object system which involves combining Go/Obj-C interfaces/protocols with being able to add virtual methods from any unit, not just the one which defines a class. The ...
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Best way to update UI when dealing with data synchronization

I'm working on a bug at work. The app is written in Objective-C for iOS based device, for the iPad. I'm the new guy there and I've been given a hard task. Sometimes, the UIButton text property does ...
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Abstracting AutoLayout sensibly - why is this so conceptually tough and where should I begin?

Below are some babbling, probably incoherent thoughts, but I am so stuck on this problem and I feel like an elegant solution is possible. Though it is indisputably awesome, and makes programatic view ...
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1answer
195 views

Do iOS frameworks require the same internal versioning as OSX frameworks?

I have been reading through the apple documentation for creating frameworks for OSX and iOS. Reading about the structure of frameworks, I began to wonder if there is really any need to create the ...
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197 views

What effect does using multiple childViewControllers views inside a ContainerViewController have on memory?

I have three childViewController views inside my ContainerViewController and these three views are inside a horizontal scroll view. My intention is to build an app that has a custom camera on one ...
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287 views

Delegate method privately called from delegate itself?

One has established design patterns so ingrained in their brain, that when sometimes somebody does something unexpected, it is a revelation. My colleague in an iOS project did call the delegate ...
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Use Objective-C protocols like Java interfaces [duplicate]

I'm a Java developer moving to Objective-C. So far in Objective-C I've seen protocols used extensively to implement the delegate pattern, but I haven't seen then to add a layer of abstraction in the ...
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166 views

Significance of many-to-many relationships? [closed]

How important are to-many relationships in iOS programming? Do you often hold a list of pointers to objects in an array in your codes? I don't think I fully understand the concept of to-many ...
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1answer
268 views

NSException in init when having a custom designated initialiser?

I have a custom View Controller that is a subclass of UIViewController that requires a data object to be set up properly. Without this object, showing the VC doesn't make any sense. So I created a ...
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5answers
909 views

New to Programming/objective c [closed]

I've recently started to work on some iPhone apps, starting from a base where I had essentially no programming experience (I studied Maths & had very few programming modules) I worked my way ...
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1answer
121 views

Using third party/ open source controls [closed]

I usually feel reluctant to use any third party or open source controls while coding in Objective-C iPhone due to following reasons. Open source controls are developed in incremental manner. So once ...
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3answers
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Is explicit else needed in initialisers? [duplicate]

I have a custom designated initialiser like this: - (id)initWithLocation:(CLLocation *)location { if (location == nil) { return nil; } self = [super init]; if (self) ...
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in Objective-C, value of type double/float can only be NAN, INFINITY, & normal number?

I knew double or float value can be not only normal value(-1.3, 0, 1.0, 2.3) but also NAN and INFINITY in Objective-C. Is there other special values except for NAN and INFINITY for double/float value ...
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1answer
162 views

How come the keyword for declaring a class is 'interface' [closed]

What is the relationship between a class and an interface in objective-c? How come we declare a class using @interface instead of @class?
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How and where is Swift and Objective-C interoperability implemented? [closed]

The question seems very generic but it does have a good meaning. For some time, I'm trying to find out exactly how objective-C and Swift can work together. I have been using them both and it works ...
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2answers
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What's the benefit of a singleton over a class in objective-c? [closed]

They both seem to take about the same amount of effort to use: Singleton: needs a .h and .m file, has to be imported into any class you want to call it from and then has to be instantiated How is ...
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Request Information from iPhone/Php developers [closed]

recently I hired a freelancer to develop an iPhone application for my website, this application will get information from the DB of the website, normally I should give to him the access to the DB to ...