Swift 4 Cookbook: The Ultimate Collection of iOS Quick Fixes

Explore the Swift 4 cookbook's organized sections and learn iOS fixes—from particle emitters in a sprite kid game to loading data with the quotable protocol, and using accelerometer and sound.

Use fast enumeration to loop through an array in Swift, printing each item to the Xcode console, while reading items into a constant named item that should not be modified.

Explore how to shuffle an array on iOS 8 and below using a shuffle extension and the fisher gates shuffle algorithm, with example code and practical tips for game play.

Compute the Manhattan distance between two CGPoints on a grid with a dedicated function. Run the code to reveal the distance between the blue and red points.

Draw a square or rectangle with core graphics addRect by setting up a context and colors, producing a red square with a green border.

Render a pdf to an image using iOS built‑in drawing APIs, handling document size, background color, and orientation, via a pre-made method that returns a rendered image or nil.

Import game play kit and generate random numbers with GKRandomSource, producing values from roughly -2 billion to 2 billion, and use the upper-bound inclusive variant for 0 to 10.

Explore how to use GameplayKit's GKRandomDistribution to generate random numbers for virtual dice, including six- and twenty-sided dice, by importing GameplayKit and using a range constructor.

Learn to run SKActions in parallel with groups, then place the group in a sequence to ensure completion; a ship shrinks to 10% while fading over four seconds.

Learn to compare two tuples in Swift 2.2 using the comparison operator for up to six elements, and beware that tuple labels are not evaluated during comparison.

Convert a float to an int using the integer constructor. This operation rounds downward, as the example shows 10 rather than 11.

Explore converting a Swift string to NSString with a simple typecast, and highlight the ongoing interoperability between Swift strings and NSString.

Master Swift string interpellation to convert data types, including integers, to a string in one line. Use the string constructor as the more common alternative.

Drag in Objective-C code to your Swift project and configure an Objective-C bridging header to enable Swift to work with Objective-C code, adding the necessary import lines.

Learn how to find the minimum of two numbers in Swift 4, ensuring both integers or both floating point types, not mixed, with example code and using the main function.

Learn how lazy variables in Swift enable calculation of work, demonstrated with a person struct featuring an age property and a Fibonacci age property that computes only when requested.

Explore swift 1.2 changes that simplify optional handling with if let, remove the pyramid of doom, add optional and forced downcasting, new annotations, a set type, and incremental builds.

Explore swift 2.0 changes, including try-catch, guard for input and optionals, strings measured by characters, and the defer keyword. It adds mutability warnings and built-in api availability checks.

Swift 3.0 introduces major changes, including function parameters with labels, lower camel case, and method syntax updates; closures become non-escaping by default, and many foundation types convert to structures.

Explore closures as anonymous functions stored in a variable to be called later. They remember the program state and are used in UI view animations and completion blocks.

Explore the float datatype, which stores low precision decimal numbers such as 3.1 and 3.14159. Understand why Swift often defaults to double and when libraries use a C float instead.

Explore how storyboards organize iOS interfaces by using layout guides for alignment, linking multiple view controllers with segues, and choosing between visual navigation and programmatic creation.

Learn to implement an image picker using UIImagePickerController to select photos from the camera roll, request photo library permission, and handle selection, cancel actions, and privacy messages.

Learn to play sounds on iOS using AVAudioPlayer by storing the player as a property, locating the sound resource, creating the audio player, then playing or stopping safely with checks.

Save a rendered image to a file by converting it to png or jpeg data with UIImagePNGRepresentation or UIImageJPEGRepresentation. Save to the documents directory and verify in Finder.