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Questions tagged [ios]

iOS is the mobile operating system running on the Apple iPhone, iPod touch, and iPad. Use this tag [ios] for questions related to programming on the iOS platform. Use the related tags [objective-c] and [swift] for issues specific to those programming languages.

It should not be confused with i5/OS, which is one of IBM's operating systems for the IBM Power Systems (originally AS/400), or with Cisco's IOS (Inter-network Operating System).

iOS Latest Stable Release: iOS 16.3.1 (20D67) released on February 13, 2023

Latest Preview: iOS 16.4 RC beta (20E246) released on March 21, 2023

Latest Release News: News and Updates

iOS is a derivative of Apple's OSX desktop operating system, with which it shares many (but not all) common frameworks and other components. These include Cocoa Touch (the counterpart of the OS X Cocoa UI Framework), the Mach/Darwin/XNU kernel and code from the Berkeley Software Distribution (BSD).

Applications for iOS are written for the Cocoa Touch framework (as opposed to OS X's Cocoa framework) using the same Xcode IDE for official use (i.e. for submitting applications to Apple's App Store) or using unofficial (mostly command-line only) toolchains for various operating systems (including Linux) for unofficial/jailbroken development. OS X is based on the Darwin-OS foundation, itself based on several Unix descendants. On June 2nd, 2014, Apple announced a new language, Swift, which could be used to develop apps for iOS. Swift was in beta until September 9th, 2014, and is, since September 17th, 2018, at version 4.2.0.

Each iOS application runs in its own secure sandbox to prevent (accidentally or intentionally) altering other applications, the operating system, or any other data. Since iOS 8, an iOS application can have extensions that extend custom functionality beyond the application. iOS is optimized for the power, graphics, processor, and memory constraints of mobile devices.

The user interface of iOS is based on the concept of direct manipulation through multi-touch gestures. Interface control elements consist of sliders, switches, and buttons, all included in Apple's UIKit Framework. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multi-touch interface.

Internal accelerometers and gyroscopes can be used by applications to respond to the user shaking the device (one application is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode or autorotation).

Apple initially adapted features from OS X to create iOS, but that cycle is now bidirectional. Many features on OS X 10.7 OSX Lion were implemented first in iOS, including application sandboxing, an OS X App Store (and the implied widespread third-party app code signing), the content-centric ("natural") scrolling direction, along with AV Foundation, Core Location, and a few other frameworks.

Swift Package Manager or SPM is a dependency manager tool from Apple for managing the distribution of the Swift code. Introduced with Swift 3.0, it is slowly becoming the dominant dependency tool in Swift and Objective-C projects. The basic concepts of the SPM are:

  • Modules - Swift code are organized in modules that specify the namespace and enforce access control of the code.
  • Packages - are reusable components of code used in the projects and at the moment these languages are supported: Swift, Objective-C, Objective-C++, C, or C++
  • Products - library or executable
  • Dependencies - modules on which code in the packages depends on

It comes as a part of the Xcode IDE Swift packages or as part of the Swift toolchains. The source code can be found here.

CocoaPods is a dependency manager for Swift and Objective-C Cocoa projects. It includes almost ten thousand libraries to help programmers scale projects. A popular alternative is Carthage, which is a decentralized dependency manager, meaning that it does not store a central list of available projects.

Use the tag for questions about Cisco's IOS operating system for Cisco network routers.

Please follow the article My App Crashed, Now What? by Ray Wenderlich, before posting any questions relating to app crashes. It explains how to properly debug an iOS app. It's pointless to ask questions relating to crashes when you don't have a proper backtrace and exception message.

Before you ask about custom controls: I want this type of control. Please visit cocoacontrols once. You will get lots of custom controls, animation, libraries, and much more which are available in Swift and Objective-C.

Before asking about a topic, just search for it in https://developer.apple.com/documentation/ also, which is the developer documentation provided by Apple that covers a lot of information regarding iOS development.

Resources

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Chat about iOS with other Stack Overflow users

If you are moving from Objective-C to Swift, but you don't know anything about Swift, then you can convert your Objective-C code/project to Swift. Use the following third-party link.

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683185 questions
561
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Detect if device is iOS

I'm wondering if it's possible to detect whether a browser is running on iOS, similar to how you can feature detect with Modernizr (although this is obviously device detection rather than feature detection). Normally I would favour feature detection…
SparrwHawk
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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: "Goodbye world" Is there a good way in Cocoa…
drewh
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Create a rounded button / button with border-radius in Flutter

I'm currently developing an Android app in Flutter. How can I add a rounded button?
Kingsley CA
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552
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36 answers

How would I create a UIAlertView in Swift?

I have been working to create a UIAlertView in Swift, but for some reason I can't get the statement right because I'm getting this error: Could not find an overload for 'init' that accepts the supplied arguments Here is how I have it…
BlueBear
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17 answers

Starting iPhone app development in Linux?

I've heard that you need to get a Mac if you want to develop iPhone apps. Is this true? Is it possible to develop iPhone apps using Linux? If yes, what do I need and where do I download the necessary tools?
javac
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546
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34 answers

How do I get the App version and build number using Swift?

I have an IOS app with an Azure back-end, and would like to log certain events, like logins and which versions of the app users are running. How can I return the version and build number using Swift?
Øyvind Vik
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545
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18 answers

How to get the screen width and height in iOS?

How can one get the dimensions of the screen in iOS? Currently, I use: lCurrentWidth = self.view.frame.size.width; lCurrentHeight = self.view.frame.size.height; in viewWillAppear: and willAnimateRotationToInterfaceOrientation:duration: The first…
griotspeak
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543
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18 answers

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?
Marco
542
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31 answers

How to set cornerRadius for only top-left and top-right corner of a UIView?

Is there a way to set cornerRadius for only top-left and top-right corner of a UIView? I tried the following, but it end up not seeing the view anymore. UIView *view = [[UIView alloc] initWithFrame:frame]; CALayer *layer = [CALayer…
tom
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537
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18 answers

How can I add a border to a widget in Flutter?

I'm using Flutter and I'd like to add a border to a widget (in this case, a Text widget). I tried TextStyle and Text, but I didn't see how to add a border.
Seth Ladd
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How to hide UINavigationBar 1px bottom line

I have an app that sometimes needs its navigation bar to blend in with the content. Does anyone know how to get rid of or to change color of this annoying little bar? On the image below situation i have - i'm talking about this 1px height line…
Szymon Kuczur
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534
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How to determine the current iPhone/device model?

Is there a way to get the device model name (iPhone 4S, iPhone 5, iPhone 5S, etc) in Swift? I know there is a property named UIDevice.currentDevice().model but it only returns device type (iPod touch, iPhone, iPad, iPhone Simulator, etc). I also…
The Mach System
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20 answers

Take screenshots in the iOS simulator

I want to take a screenshot of my iOS application when it is running in the simulator, and save the screenshot on my Mac. How can I do this?
Shreyash Mahajan
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525
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82 answers

Getting error "No such module" using Xcode, but the framework is there

I'm currently coding in Swift, and I've got an error: No such module Social But I don't understand, because the module is in my project, declared in "Linked frameworks and Libraries" and in "Embedded Binaries". The frameworks is in Objective-C, so…
alexandresecanove
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How can I set the title of a UIButton as left-aligned?

I need to display an email address on the left side of a UIButton, but it is being positioned to the centre. Is there any way to set the alignment to the left side of a UIButton? This is my current code: UIButton* emailBtn = [[UIButton alloc]…
Madan Mohan
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