Create a project, Application development using XIB.

Last Updated: 2021/09/11

Introduction

Just as there is more than one recipe for curry, there is more than one way to develop an iOS app.
The method I'm going to introduce here is the standard way I do it, but it is not necessarily the best. There is a best way for each project and each person.
I hope that my recipe presented here is a flavor that suits you.

Environment

⛏ Xcode 12.5
🕊 Swift 5.3.2
🍎 macOS BigSur 11.1
📱 iOS 13.0 ~ 14.5

Sample

Here is a sample. 👉 DoshCook/SwiftRecipesSample.

Create A Project

Let's create a project.

Select iOS > App > next.(Figure 1)

Figure 1

Add a Product Name and configure as follows.(Figure 2)

Item	Select Item
Interface	Storyboard
Life Cycle	UIKit App Delegate
Language	Swift

Figure 2

Organize Your Directory

Organize the files you have from the beginning.

The configuration at the time of project creation is as follows.

.
├─ ProjectName.xcodeproj
└─ ProjectName
    ├── AppDelegate.swift # Manage the entire app lifecycle.（required）
    ├── Assets.xcassets # Manage images and colors.
    ├── Base.lproj # LaunchScreen.storyboard and Main.storyboard are included.
    ├── Info.plist # A file that configures the information needed to run the application.（required）
    ├── SceneDelegate.swift # Manage Scenes.
    └── ViewController.swift # ViewController provided by default.

Split it in Resources, Scripts and Storyboards.

.
├─ ProjectName.xcodeproj
└─ ProjectName
    ├── Scripts
    |    ├── AppDelegate.swift
    |    ├── SceneDelegate.swift
    |    └── ViewController.swift
    ├── Resources
    |    ├── Info.plist
    |    └── Assets.xcassets
    └──  Sotryboards
        └── Base.lproj

Make sure that the project tree in Xcode and the structure in the actual directory match as shown in Figure 3 and Figure 4.

Figure 3

Figure 4

Because we changed the location of Info.plist, we get the following error and cannot build.

Build input file cannot be found: '/Users/uruly/DoshCook/XcodeProjects/SwiftRecipesSample/SwiftRecipesSample/Info.plist'

Modify Info.plist in Build Settings to be under Resources. (Figure 5)

Figure 5

I basically organize my projects into folders like this.

About SceneDelegate

Starting with iOS13, SceneDelegate.swift is generated in the project as a template. It is used to split the same app and open it at the same time, as shown in Figure 6 below.

Figure 6
Reference: Scenes | Apple Developer Documentation

If SceneDelegate is not used

If you want to support iOS13 or lower, or if you don't want multiple screens to be activated, follow the steps below to delete the file.

Delete Application Scene Manifest from Info.plist.（Figure 7)

Figure 7

Delete UISceneSession Lifecycle from AppDelegate.swift.

Remove the code from AppDelegate.swift as shown below.

// Remove the following.
// MARK: UISceneSession Lifecycle

func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
    // Called when a new scene session is being created.
    // Use this method to select a configuration to create the new scene with.
    return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
}

func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
    // Called when the user discards a scene session.
    // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
    // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
}

Add var window: UIWindow? to AppDelegate.swift.

import UIKit

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    // Add
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        return true
    }
}

Delete SceneDelegate.swift

Development Using XIB

There are many ways to develop iOS applications, even just using the Swift language, and the same goes for the implementation of the UserInterface (UI). There are two ways to implement a UserInterface (UI): using an Interface Builder (IB) such as Storyboard / xib / SwiftUI, and writing code.

Storyboard
xib
SwiftUI
code only(UIKit)

Why Use XIB?

Each method has its own merits and demerits, but in this article, we will only compare Storyboard and xib.

Storyboard and xib are both IB-based methods. Storyboard has the advantage of clear screen transitions, but has disadvantages such as conflicts during team development and difficulty in injecting dependencies (DI) in the initializer. Therefore, we choose to develop using xib.

	Team Development	DI
xib	○	○
Storyboard	△	△

What is DI in the initializer?

If you use xib, you can pass the value in the initializer as follows.

import UIKit

final class ViewController: UIViewController {
    
    private let initialText: String

    // DI
    init(initialText: String) {
        self.initialText = initialText
        super.init(nibName: "ViewController", bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
}

// Generating
let viewController(text: "The value you want to pass in the initializer.")

In the case of Storyboard, DI in the initializer has been available since iOS13.

class ViewController: UIViewController {

    private let initialText: String

    init?(coder: NSCoder, initialText: String) {
        self.initialText = initialText
        super.init(coder: coder)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

// Generating
let storyboard = UIStoryboard(name: "ViewController", bundle: nil)
let viewController = storyboard.instantiateInitialViewController { coder in
    ViewController(coder: coder, initialText: "The value you want to pass in the initializer.")
}

Reference: https://qiita.com/shtnkgm/items/cad6f52c489612628fd4

These can be used in combination. The way to do this varies depending on the project you are participating in. Although it is difficult to decide whether it is good or bad, we will basically implement it using xib in this site.

Create A View

Create Views folder under Scripts.
Since the ViewController is going to be named CreateProjectSampleViewController, I created a folder called CreateProjectSample.

The current configuration is as follows.

.
├─ ProjectName.xcodeproj
└─ ProjectName
    ├── Scripts
    |    ├── AppDelegate.swift
    |    ├── SceneDelegate.swift
    |    └── Views
    |         └── CreateProjectSample
    |               ├── CreateProjectSampleViewController.swift
    |               └── CreateProjectSampleViewController.xib
    ├── Resources
    |    ├── Info.plist
    |    └── Assets.xcassets
    └──  Sotryboard
        └── Base.lproj

Select New > File > Cocoa Touch Class and Next.（Figure 8)

Figure 8

Create CreateProjectSampleViewController and check Also create XIB file. (Figure 9)

Item	Select Item
Class	CreateProjectSampleViewController
Subclass of	UIViewController
Also create XIB file	Checked
Language	Swift

Figure 9

Display Of The First View

When using Storyboard, the screen pointed to by the arrow (→) on the Storyboard will be opened after the application starts. For development using xib, you need to indicate the screen that will be opened at startup with code.

Remove the Main.storyboard.
Remove the Main storyboard file base name from Info.plist.(Figure 10)

Figure 10

Configure the screen that opens when the app is launched on the code.
The location to specify the startup screen depends on whether you use SceneDelegate.swift or not.

When using SceneDelegate.swift
If using SceneDelegate, Remove the Storyboard Name from Info.plist > Application Scene Manifest > Scene Configuration > Application Session Role > Item 0(Default Configuration).(Figure 11)

Figure 11

In SceneDelegate.swift, put the following in scene(_:willConnectTo:options:).

import UIKit

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        guard let windowScene = (scene as? UIWindowScene) else { return }
        // Generate window.
        let window = UIWindow(windowScene: windowScene)
        // Specify the ViewController you want to open at the first startup.
        let viewController = CreateProjectSampleViewController(nibName: "CreateProjectSampleViewController", bundle: nil)
        // Set to window root.
        window.rootViewController = viewController
        // Display window.
        window.makeKeyAndVisible()
        // Make self.window the generated window.
        self.window = window

    }
}

When SceneDelegate.swift is not used
If you don't use SceneDelegate, put the following in application(_:didFinishLaunchingWithOptions) of AppDelegate.swift.

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        // Generate window.
        let window = UIWindow(windowScene: windowScene)
        // Specify the ViewController you want to open at the first startup.
        let viewController = CreateProjectSampleViewController(nibName: "CreateProjectSampleViewController", bundle: nil)
        // Set to window root.
        window.rootViewController = viewController
        // Display window.
        window.makeKeyAndVisible()
        // Make self.window the generated window.
        self.window = window

        return true
    }

}

Now we are ready to develop using xib.
We will proceed with development by placing ViewController under Views.

Conclusion

Many of the recipes introduced on this site will be based on this project creation method.

Swift Recipes