Book Image

SwiftUI Essentials – iOS 14 Edition

By : Neil Smyth
Book Image

SwiftUI Essentials – iOS 14 Edition

By: Neil Smyth

Overview of this book

Do you want to create iOS apps with SwiftUI, Xcode 12, and Swift 5.3, and want to publish it on the app store? This book helps you achieve these skills with a step-by-step approach. This course first walks you through the steps necessary to set up an iOS development environment together and introduces Swift Playgrounds to learn and experiment with Swift—specifically, the Swift 5.3 programming language. After establishing key concepts of SwiftUI and project architecture, this course provides a guided tour of Xcode in SwiftUI development mode. The book also covers the creation of custom SwiftUI views and explains how these views are combined to create user interface layouts, including the use of stacks, frames, and forms. One of the more important skills you’ll learn is how to integrate SwiftUI views into existing UIKit-based projects and explain the integration of UIKit code into SwiftUI. Finally, the book explains how to package up a completed app and upload it to the app store for publication. Along the way, the topics covered in the book are put into practice through detailed tutorials, the source code for which is also available for download. By the end of this course, you will be able to build your own apps for iOS 14 using SwiftUI and publish it on the app store. The code files for the book can be found here: https://www.ebookfrenzy.com/retail/swiftui-ios14/
Table of Contents (56 chapters)
56
Index

39.4 Declaring File Type Support

A key step in implementing document support is declaring the file types which the app supports. The DocumentGroup user interface uses this information to ensure that only files of supported types are selectable when browsing. A user browsing documents in an app which only supports image files, for example, would see documents of other types (such as plain text) grayed out and unselectable within the document list. This can be separated into the following components:

39.4.1 Document Content Type Identifier

Defining the types of file supported by an app begins by declaring a document content type identifier. This is declared using Uniform Type Identifier (UTI) syntax which typically takes the form of a reverse domain name combined with a common type identifier. A document identifier for an app which supports plain text files, for example, might be declared as follows:

com.ebookfrenzy.plain-text

39.4.2 Handler Rank

The document content...