Swift is a modern, open-source programming language developed by Apple as a replacement to their earlier language, Objective-C.
It can be used on Mac devices to develop software that target all Apple platforms: iOS, macOS, watchOS, and tvOS, while being deeply integrated into Apple's IDE: Xcode.
In the following official Apple documentation, there are many other resources, such as videos, interactive demos, and guided exercises, you can use to better understand and practice these tools.
Swift Getting Started Documentation
While languages such as React Native allow you to build multi-platform apps, such as for iOS and Android, using only one source code, Swift offers many tools that make it easy to quickly build apps that work specifically throughout all of Apple's ecosystem of platforms.
Apps built through Swift can intuitively support iPhone and iPad screens at the same time, utilizing design patterns and themes that fit Apple's design policy to match the expected user experience on an iOS device.
You will have access to an assortment of developer kits that make it simpler to integrate various, native features into your app. For example, WidgetKit can help set up widgets for iOS Home Screens for your app, or HealthKit can allow you to communicate to a user's health and fitness data, with their permission.
It comes built-in with over 4000 customizable icons and symbols that are designed to seamlessly match Apple software, which you can view and modify through SF Symbols 4.
These are just some of the many advantages available.
In 2019, Apple introduced a new framework for building user interfaces called SwiftUI. This is a declarative UI toolkit, similar to React, where we can tell it what components we want and the framework will handle performing the steps needed to get that result.
Hacking with Swift is a great free resource for learning how to do specific things in Swift and SwiftUI when the issues arise.
After launching Xcode, selecting Create a new Xcode project, and choosing which platform and type of app you want to make, you will then have
to fill in the following info:
This information can be changed later, so for starters you can leave Team to be empty, as this is only necessary for deploying the app to the App Store. Organization identifier is used to uniquely identify your app once it is up on the App Store, so you can choose whichever name you'd like, such as your name or group's name. Do note Organization identifier cannot be changed once the app is uploaded to the App Store but it is purely meta data.
Make sure to use SwiftUI and Swift as your interface and language respectively, then click Next to choose where to store your project, and now you're ready to start.
Xcode has built-in simulators for many Apple devices you can use to run your code and see how it performs. You can also download new simulators for specific a device and operating system version to test different scenarios, such as an iPhone 11 running iOS 13.
If you have your own Apple device, you can also connect it to your Mac device and run your app on it for testing. Note that as of iOS 14, from your device, you will have to first go to Settings > Privacy & Security > Developer Mode first to allow your device to run apps downloaded from Xcode.
Learn about the different data types in Swift. Each language has its own nuances in how variables are declared and stored, useful to become familiar with it before starting to code.
SwiftUI has many property wrappers that provide different functionality to the object instances they are attached to. These are an important tool for making your code efficient and storing your objects properly. In particular, you should be aware of what the @State and @Binding wrappers do.
Learn about Protocols for defining properties object models must have. These function similar to what are known as Interfaces in other languages. Protocols are important as you will sometimes run into errors that require the object you are using to "conform" to some protocol. For example, if you are trying to loop over a custom object, you must first have that object conform to Identifiable so that Swift can iterate through a list of that object and recognize which entries are unique.