Swift is a newly developed programming language which is developed by Apple Inc for OS X development and iOS. This is completely designed to work with Cocoa Touch Framework and the existing body of Objective-C (ObjC) code written for the Apple products.
This programming language initially releases on 19th September 2017 with version 4.0. It can be operated by operating system LINUX, FreeBSD & Darwin.
Swift designers took ideas from various other popular languages such as Objective-C, Rust, Haskell, Ruby, Python, C#, and CLU.
A Tour: Swift Environment
Local Environment Setup
Swift 4 works in Playground platform in the backend. So, we will explain the same. First, you need to get Xcode software to start your Swift 4 coding in Playground. Once you comfortably have done with the concepts of Swift 4, you can use Xcode IDE for ISO/OS x app development.
Let’s go, we expect you must have an account at Apple Developer website for sure. Once you are logged in to the website, go to the following link − Download for Apple Developers.
Now you will see few software availabilities as follows:
Now you have to select Xcode and download it by clicking on the given link near to disc image. Then, download the dmg file, once your download has done then, you can install it by following the given instructions. In the End, just follow the given instructions and drop Xcode icon into the Application folder.
Now you have Xcode installed on your machine. Next, open Xcode from the Application folder and proceed after accepting the terms and conditions.
Now select ‘Get started’ with a playground option and then you have to enter a name for a playground and select iOS as a platform. Finally, you will get the Playground window as follows –
You will see the default Swift 4 Playground Window.
If you, again and again, create the same program multiple times for OS X program, then it will include import Cocoa and the program will look like as follows –
When the above program gets loaded, it should display the following result in Playground result area (Right Hand Side).
Congratulations, you have your Swift 4 programming environment ready.
Swift First Program
A quick look for a simple program of “Hello, World!” with the reference of OS X playground, which includes Import Cocoa as-
If we create program for iOS playground, then it will take import UIkit and the program will look like as-
A Swift program imports Objective-C framework and library directly in Swift program. Swift developers can also add C and C++ into Swift applications.
Why Swift Language
It’s not just for iOS
Swift works great on Apple platforms. Also, you can make use it on Linux, with Apple’s built-in binaries for Ubuntu. It’s for developers who want to write code server-side and client-side as it opens up opportunities for sharing functionality.
It’s an easy language to learn
Apple learning Swift is as easy as much possible. Let’s take a quick “Tour”, create playgrounds and even use “IBM Swift Sandbox” if you want to play with Swift in an online REPL.
Swift is built with the future in mind
Swift language takes what is great about Objective-C and brings a whole host of new techniques & features that make it a language that you wish love to use to solve virtually any problem in a quick row.
This is a fast, flexible and powerful language. Swift supports inferred types meaning you can create strong, statically typed code quickly. Some functional programming patterns that are part of the language, such as map and filter functions.
It uses the LLVM compiler which is written in C++ and developed to design run-time, compile-time to generate native code optimized for the platform that it’s running on.
Great tools and ecosystem (even if you hate Xcode)
In a written statement of Swift code, you will more than likely be using Xcode, the IDE that maintains Apple continuously that lets you write Swift and includes an interface builder and simulators for different types of Apple-specific platforms that you can write apps for. Not a fan of Xcode? You can further use Xcode and potentially to your existing text editors like as Auto-Completion, including Sublime Text, Textmate, and VIM.
Swift recently launched its packages like as Carthage, Cocoapods, and the Swift Package Manager (SPM). The SPM was created by Max Howell, of Homebrew fame, and Matt Thompson. Apple released at the same time as Swift was open source language guide and it also looks likely to the de facto package management solution for Swift code.
A playground is an area in XCode 6, where the programmer writes their programming for experiments. It looks like a simple editor window where you can write code. The code is compiled and executed immediately. There is no need to build the project, and then run the emulator in order to test it. Everything runs simultaneously: you write code and instantly see the result.
Career Opportunities with Swift-iOS
Generally, iOS apps are known to be more profitable than Android apps. Although companies always prefer getting an iOS app first and thereafter, there is a high demand for skilled Swift Developers. According to indeed.com, the average offered the salary for Swift developers is up to 112k USD, which is higher than the average offered salary for other language skills.
New Features in Swift 4
- It is easier to use and faster to get run strings that hide the Unicode connection. It also adds support for creating, using and managing substrings in a program.
- Smart key features in Swift like finding the paths for such type-safe, efficient, and extensible key-value coding.
- Enhancements to creating and manipulating Dictionary and Set types.
- It extends support for serialization to the data types like struct, enum types and enables type to get external formats such as JSON and pList in the format.
- Enforced exclusive access to memory
How to run flow in Swift
Generally, you need to set up the local environment.
- Now, programmers need to install Xcode on their machine. After approval of the terms and conditions, open your Xcode from the application folder window.
- After, you start with the option “get started” with playground option.
- Then, Enter your playground name along with the platform name (select IOS).
- Finally, you will get the Playground window.
How to compare Swift and Objective-C
Built-In Data Types in Swift
A data type of mathematical, relational or logical operations can be applied to it without causing an error. Some of data types are provided by Swift language.
- Int or UInt − This is for all numbers, you can use Int32, Int64 to define 32 or 64 bit signed integer, whereas UInt32 or UInt64 to define 32 or 64-bit unsigned integer variables. For example, 42 and -23.
- Float − This shows a 32-bit floating point number. Developers mostly use it when floating point values do not contain 64 bi-precision. For example, 3.14159, 0.1, and -273.158.
- Double – This is used to represents a single bit floating point number. Programmers need to use it when floating point values are very large or particularly precise. For example, 3.14159, 0.1, and -273.158.
- Bool – This shows Boolean value, It must be either true or false.
- String − This is a complete order collection of characters as a single unit. For example, “Hello”.
- Character − This is a single-character string literal. For example, “C”
- Optional − A single variable either holds a value or no value.
- Tuples − This defines group multiple values in single Compound Value.
It has some quality where developers can represent a variable classification that can hold either a value or no value.
Swift Language Guide
Swift plays a very vital role in modern programming. Let’s take a look at its credentials and body structure.
Arrays in Swift
Arrays are those type of arrays which applicable for storing multiple values in order lists of any individual type. Swift programming set up a strict checking mechanism where programmers cannot enter or insert any wrong type in an array even by mistake, i.e. Swift arrays always vary in Objective-C. NSArray and NSMutable Array element which stores any type of object and it does not provide any information about the nature of the class object which they return.
Shorthand syntax for Arrays
A swift array can also be written in this format as – Array<SomeType>, where ‘SomeType’ is the type that the array is going to store. A developer now can also write the type of an array in shorthand form as Some Type[ ].
Accessing and Modifying Arrays
Arrays in swift can be modified easily with help of “append()” function method or by using the addition operator function (+=) for inserting new data items at the end of an array.
The empty Property in Swift
Developers usually use the read-only empty property of arrays to get an array is empty or not. Here is a simple example showing the use of an empty property.
Grand Central Dispatch in Swift
It defines newly features as runtime libraries and system enhancements in Swift and it also provides systemic, comprehensive improvements support for concurrent code execution on multicore hardware in iOS and OS X.
Why GCD in Swift
One of the biggest challenges today for developers is the ability to keep your app responsive in response to users, the bigger your app gets, the more functions and functionality you will add and the slower it gets and subsequently the less user-friendly your app becomes. Well not anymore.
You can use GCD to run your app threads and present information to the user. For example, let’s understand that you want to Parse JSON in Swift, the JSON file contains data in a large format and it takes around 10 seconds.
Lets’ explain with an example:
This function replaces by REST API call to the server. For the purpose of this project I have just added in this line:
This creates a stoppage execution time of around 25 seconds which gives a quite slow response from the server side and therefore, highlighting the need to use Grand Central Dispatch.
We then have an IBAction which will trigger when we click a button and run the above code.
Detecting low Power Mode in Swift
Detecting low power mode is also known for LowPowerModeEnabled, then listen to the state change using the section like NSProcessInfoPowerStateDidChangeNotification.
An act of present, Xcode- iOS simulators do not have the option to get on enable or disable Low Power Mode. To test this project, you will need to put this on your device.
How to create Detect Low Power Mode Project in Swift
The first thing we need to do is declare some variables at the top. So, in your ViewController.Swift file. just under the class declaration, write:
An NSProcessInfo function retrieves data automatically. Now, we are going to create a function that will start the download:
Now, we are going to implement the powerModeChanged(_:) method.
That’s a quick solution for detecting low power mode in your applications and providing alternatives backup for downloading to the end user.
How to work with JSON in Swift
When an application commonly communicates with a web application and that gives information in return from the server is often format as JSON. You merely use the foundation framework JSON-Serialization class to convert JSON data into Swift data types like Dictionary, Array, String, Number, and Bool. However, because you will not be sure about the structure or values of JSON your application receives, it could be challenging to deserialize model objects correctly. This post describes many approaches where you can take when working with JSON in your applications.
Extracting values from JSON
The JSON serialization contains unique and individual class methods which call as JsonObject (with options) which returns a value of type Any and it gives an error if the data do not parse.
In programming, JSON may or may not contain only a single added values. To get a Dictionary value from a JSON object type, conditionally cast it as [String: Any]. To get a single arrays value from a multiple JSON array type, conditionally it will cast it as [Any] (or an array with a more specific element type, like [String]). You can extract a dictionary value by key or an array value by index using a typecast optional binding with subscript accessors or pattern matching with enumeration.
An enumeration function in Swift 4 language also resembles the structure of C language and Objective C.
- It declares in a class and its value gets through the instance of that class.
- Initial member value which defines using enum intializers.
- Its functionality extends to standardization of protocol functionality.
When we run above program we will get an output
ARC overview in Swift
ARC mainly uses for initialization and de-initialization for the system resources. Releasing memory spaces keep maintaining the object class instances when the instances are no longer need. ARC always keeps track of important information about the relationships between our code instances to manage the memory resources in an effective manner.
Functions of ARC
- ARC allocates a piece of memory which stores the classified information of time allocation when a new class instance created by init() function.
- Information about the instance type and its value stored in memory.
- When the class instance is no longer available, then its automatically gets free the memory space by init() for further class instance storage and retrieval.
- ARC maintains track of currently referring class instances properties, constants, and variables so that init() apply only to those unused instances.
- ARC contains ‘strong reference’ to get those classes’ instance property, constants and variables to restrict de-allocation when the class of the instance is being currently in use.
The Good and the Bad of Swift
iOS is the world’s second-largest mobile platform. Many countries including the USA, UK, and France, there Apple devices are the only devices which continue to outperform Android in smartphone sales numbers. That the only reason why so many businesses focus their software products on the iOS platform as a key investment opportunity.
If you are one of those smart business owners following the iOS app development path, probably the most important decision you will make is choosing the right tech stack for your product. If you ever make a decision to go with native development instead cross-platform solutions, you still have to decide which language to use: the good old Objective-C or brand-new Swift.
Although, it did not prevent Swift language from becoming the “Most Loved” technology. According to the 2015 Stack Overflow Developer Survey.
Since Apple decided to make Swift language to an open sourced language in 2015, its growth has been tremendous since then. Around 60,000 people have taken Swift project in the first week after its release announcement. Now, Swift has become officially the fastest growing language in history, according to TIOBE Index: The language reached the top 10 in March 2017.