Xcode-Swift; 向启动屏幕添加声音效果

Question

Just really quickly wanted to enquire about a minor issue i'm having with trying to get a sound effect playing within my launch-screen of my swift application. I'm more-so confused in regards to where I'm meant to declare my AVAudio player (in my view controller or Appdelegate); but haven't had success in either methods. Here is what i've currently got within my appDelegate file

import UIKit
import AVFoundation

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var audioPlayer = AVAudioPlayer()

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

            self.window = UIWindow(frame: UIScreen.main.bounds)
            self.window!.backgroundColor = UIColor(red: 9/255, green: 4/255, blue: 68/255, alpha: 1)
            self.window!.makeKeyAndVisible()

            // rootViewController from StoryBoard
            let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let navigationController = mainStoryboard.instantiateViewController(withIdentifier: "navigationController")
            self.window!.rootViewController = navigationController

            // logo mask
            navigationController.view.layer.mask = CALayer()
            navigationController.view.layer.mask!.contents = UIImage(named: "logo.png")!.cgImage
            navigationController.view.layer.mask!.bounds = CGRect(x: 0, y: 0, width: 60, height: 60)
            navigationController.view.layer.mask!.anchorPoint = CGPoint(x: 0.5, y: 0.5)
            navigationController.view.layer.mask!.position = CGPoint(x: navigationController.view.frame.width / 2, y: navigationController.view.frame.height / 2)

            // logo mask background view
            let maskBgView = UIView(frame: navigationController.view.frame)
            maskBgView.backgroundColor = UIColor.white
            navigationController.view.addSubview(maskBgView)
            navigationController.view.bringSubview(toFront: maskBgView)

            // logo mask animation
            let transformAnimation = CAKeyframeAnimation(keyPath: "bounds")
            transformAnimation.delegate = self as? CAAnimationDelegate
            transformAnimation.duration = 1
            transformAnimation.beginTime = CACurrentMediaTime() + 1 //add delay of 1 second
            let initalBounds = NSValue(cgRect: (navigationController.view.layer.mask!.bounds))
            let secondBounds = NSValue(cgRect: CGRect(x: 0, y: 0, width: 50, height: 50))
            let finalBounds = NSValue(cgRect: CGRect(x: 0, y: 0, width: 2000, height: 2000))
            transformAnimation.values = [initalBounds, secondBounds, finalBounds]
            transformAnimation.keyTimes = [0, 0.5, 1]
            transformAnimation.timingFunctions = [CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut), CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)]
            transformAnimation.isRemovedOnCompletion = false
            transformAnimation.fillMode = kCAFillModeForwards
            navigationController.view.layer.mask!.add(transformAnimation, forKey: "maskAnimation")

            // logo mask background view animation
            UIView.animate(withDuration: 0.1,
                           delay: 1.35,
                           options: UIViewAnimationOptions.curveEaseIn,
                           animations: {
                            maskBgView.alpha = 0.0
            },
                           completion: { finished in
                            maskBgView.removeFromSuperview()
            })

            // root view animation
            UIView.animate(withDuration: 0.25,
                           delay: 1.3,
                           options: UIViewAnimationOptions(),
                           animations: {
                            self.window!.rootViewController!.view.transform = CGAffineTransform(scaleX: 1.05, y: 1.05)
            },
                           completion: { finished in
                            UIView.animate(withDuration: 0.3,
                                           delay: 0.0,
                                           options: UIViewAnimationOptions(),
                                           animations: {
                                            self.window!.rootViewController!.view.transform = CGAffineTransform.identity
                            },
                                           completion: nil
                            )

                            do {
                                self.audioPlayer = try AVAudioPlayer(contentsOf: URL.init(fileURLWithPath: Bundle.main.path(forResource: "startup", ofType: "wav")!))
                                self.audioPlayer.prepareToPlay()
                            }
                            catch {
                                print(error)
                            }
            })

            return true

    }



    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }


}

Answer 1

The method I prefer to use is declaring

var audioPlayer = AVAudioPlayer()

in the AppDelegate (as you did in your code).

And having a method for playing the audio

func playSound(file:String, ext:String) -> Void {
    do {
        let url = URL.init(fileURLWithPath: Bundle.main.path(forResource: file, ofType: ext)!)
        audioPlayer = try AVAudioPlayer(contentsOf: url)
        audioPlayer.prepareToPlay()
        audioPlayer.play()
    } catch let error {
        NSLog(error.localizedDescription)
    }
}

This way, you can call

playSound(file: "startup", ext: "wav")

to play this sound (and other sounds too) anywhere and anytime in your app, with minimal code duplication.

Answer 2

I have faced some similar issues when I wanted to do a handshake call at the splash. But according to Apple UX, the user should be able to go to landing as fast as possible.

The launch screen prepares your view and application before. We cant control it. But the launch screen time can be reduced if we dont do much heavy task in the landing view controller or do that in a separate thread. This way launch screen time is reduced.

To do that sound effect, you can make a initial VC and call replicate the same UI as launchscreen so transition wont be visible. And at there you can perform your Audio stuff in viewDidLoad() or viewDidAppear(animated:Bool)