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Notification
A browsable archive of writing and notes across the site.
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UserDefaults and Keychain
Apple offers several persistence options, and UserDefaults and Keychain are the two you reach for most often in day-to-day app development. From past conversations with colleagues …
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In-app purchase
If your app ships on the App Store, in-app purchase (IAP) is something you can’t really avoid. Last year’s spat between WeChat tipping and Apple put IAP in the …
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Dependency injection using factories in Swift
Original: Dependency injection using factories in Swift Original author & copyright: @johnsundell Dependency injection is one of the key tools for making code more testable. …
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Handling non-optional optionals in Swift
Original: Handling non-optional optionals in Swift Original author & copyright @johnsundell Optionals are arguably one of the most important features of Swift, and one of the …
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Understanding responders and the responder chain
Apps receive and handle events through responder objects. A responder is an instance of the UIResponder class — and UIView, UIViewController, and UIApplication, all the usual …
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Capturing objects in Swift closures
Original: Capturing objects in Swift closures Original author @johnsundell Ever since blocks were introduced to Objective-C in iOS 4, they’ve been a core part of the most …
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@autoclosure && @escape
Closures are first-class citizens in Swift, which means you can pass them around as arguments. While learning Swift, you keep running into keywords that decorate these closure …
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Everything you need to know about iOS 10 notifications
Overview Push notifications are something we’re all familiar with — pretty much anyone with a smartphone gets interrupted by them every day. The right notification is a …
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Building an elastic view animation with UIBezierPath
Original: Elastic view animation, or how I built DGElasticPullToRefresh Author: @gontovnik DGElasticPullToRefresh demonstrates a springy elastic effect. Here’s what it looks …
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A bit about Category in Objective-C
A category in Objective-C is a compile-time mechanism that lets you tack extra methods onto an existing class. There’s one catch: you can’t add new instance variables …
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Understanding the Objective-C runtime
The Objective-C runtime is one of those language features that’s easy to overlook when you’re just stepping into Cocoa/Objective-C land. The reason is simple: …
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How we built the Guillotine menu animation for iOS
Original: How We Created Guillotine Menu Animation for iOS Author: @johnsundell Ever wondered why nearly every app’s menu is a sidebar? Why isn’t it a topBar, a …
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[257] Binary Tree Paths
Problem: 257. Binary Tree Paths Given a binary tree, return all root-to-leaf paths. For example, given the following binary tree: 1 / 2 3 5 All root-to-leaf paths are: …
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[018] Length Of Last Word
Problem Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length of last word in the string. If the last word does not …
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iOS remote push notifications: a deployment walkthrough
iOS push notification setup has been driving me crazy for the past few days, so I’m writing up everything I learned for anyone else who might run into the same wall. How iOS …