Game crashing when i run this function? - swift

It's meant to be sound whenever the player collects a coin, but instead as soon as the character touches the coin the game freezes and exits.
func playTap() {
if let url = Bundle.main.url(forResource: "tap", withExtension: "caf"){
tap = try AVAudioPlayer(contentsOf: url)
guard let tap = tap else { return }
tap.prepareToPlay()
tap.play()
} else {
print(error.localizedDescription)
}
}

I'm guessing your code is crashing at since you are trying to FORCE UNWRAP a null optional with the ! at the end of the line.
let url = Bundle.main.url(forResource: "tap", withExtension: "caf")!
Try
if let url = Bundle.main.url(forResource: "tap", withExtension: "caf"){
//Code here
} else {
}
or
guard let url = Bundle.main.url(forResource: "tap", withExtension: "caf") else {}
EDIT
Spell check key values!!

Related

How do you fix the "found nil while unwrapping optional value" error when trying to play sound?

I'm making a function to play sound
func playSound(soundName: String) {
let url = Bundle.main.url(forResource: soundName, withExtension: "wav")
player = try! AVAudioPlayer(contentsOf: url!)
player.play()
}
Then call this function in an IBAction that contains all my buttons
#IBAction func buttonPiano(_ sender: UIButton) {
playSound(soundName: String(sender.currentTitle!))
sender.backgroundColor = UIColor.white
sender.alpha = 0.3
DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(300), execute: {
sender.backgroundColor = UIColor.systemBackground
sender.alpha = 1
})
}
Running the app I can do. But whenever you press a button, it crashes and gives me this error:
Fatal error: Unexpectedly found nil while unwrapping an Optional value: file /Users/administrator/Desktop/Xcode Projects/pianoButtons/pianoButtons/ViewController.swift, line 37
The optional value seems to be url! from my sound function.
I've tried all I could, but no luck. How do I avoid this error and play the sound without crashes?
Make sure that your soundName.wave file is shown inside the copy bundle resources. You can find that by clicking on your project > selecting your target > Build Phases > Copy Bundle Resources. If you do not see it there, click the plus button to add it.
var soundPlayer: AVAudioPlayer?
func playSentSound() {
DispatchQueue.main.async{
let path = Bundle.main.path(forResource: "soundName.mp3", ofType: nil)!
let url = URL(fileURLWithPath: path)
do {
self.soundPlayer = try AVAudioPlayer(contentsOf: url)
print("Playing")
self.soundPlayer?.play()
} catch {
// couldn't load file :(
print("Cant Load File")
}
}
}
Your code is essentially calling this
try! AVAudioPlayer(contentsOf: Bundle.main.url(forResource: String(button.currentTitle!), withExtension: "wav")!)
Each ! is a potential crash. This is when they would occur
The button may not have a current title at the time the action is triggered.
The main bundle may not have a resource with that name/extension
The audio player may not be able to play the contents of that file
In your specific case it seems like it is failing at 2. The nicer way to handle this is like so
if let url = Bundle.main.url(forResource: soundName, withExtension: "wav") {
player = try! AVAudioPlayer(contentsOf: url)
} else {
print("No resouce named \(soundName).wav")
}
First of all your app will just not play a sound instead of crashing, second you will get a helpful log message which might show you why the resource isn't being found.
Ideally all of your ! should be replaced with similar constructs, to log errors or perform some fallback action instead of crashing.

How to play sound after each network request is successful?

I want to play a sound after each network request is successful. I have some objects that I want to send to the server using a for loop. In each iteration I'm sending a request to the server and after each request is complete, I want to play a sound.
I've tried this:
for object in objects {
sendObjectToServer(object)
}
func playSound() {
let url = Bundle.main.url(forResource: "sound", withExtension: "mp3")!
let player = try! AVAudioPlayer(url)
player.play()
}
func sendObjectToServer(object: Object) {
URLSession.shared.dataTask(with url: object.url) {(data,response,error) in
DispatchQueue.main.async {
playSound() // doesn't play sound synchronously
}
}
}
Why are you using the main thread for background-related operations. Only update your UI in the Dispatch.main.async code:
Try this on a physical device (tested and worked)
import AVFoundation
for object in objects {
DispatchQueue.global(qos: .background).async {
sendObjectToServer(object)
}
}
var player: AVAudioPlayer?
func playSound() {
guard let url = Bundle.main.url(forResource: "sound", withExtension: "mp3") else { return }
do {
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default)
try AVAudioSession.sharedInstance().setActive(true)
/* The following line is required for the player to work on iOS 11. Change the file type accordingly*/
player = try AVAudioPlayer(contentsOf: url, fileTypeHint: AVFileType.mp3.rawValue)
/* iOS 10 and earlier require the following line:
player = try AVAudioPlayer(contentsOf: url, fileTypeHint: AVFileTypeMPEGLayer3) */
guard let player = player else { return }
player.play()
} catch let error {
print(error.localizedDescription)
}
}
func sendObjectToServer(object: Object) {
URLSession.shared.dataTask(with url: object.url) {(data,response,error) in
// Custom Logic
playSound()
}
}

play multiple AVAudioPlayer at the same time asynchronously?

I have a background AVAudioPlayer who normally works just fine. Now I have some event that triggers an asynchron action with a delay, here I want to play another sound while the other should keep playing. So I make a new one:
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
guard let urlStr = Bundle.main.path(forResource: "File1", ofType: ".mp3") else { fatalError() }
self.player = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: urlStr), fileTypeHint: "mp3")
self.player?.play()
}
DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
guard let urlStr = Bundle.main.path(forResource: "File2", ofType: ".mp3") else { fatalError() }
let p = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: urlStr), fileTypeHint: "mp3")
p?.play()
}
So the first one runs normally (Dispatch only to show that it's working also async). The second one runs as well, meaning no error. However, I only hear the first one...
Why do you create a new player inside you async call? I had similar problems and it should work if you declare a new var outside your immediate async-scope.

Swift / iOS 10 : How to download a VIDEO and store within the app

I'm new to SWIFT/Programming &
I couldn't find an answer on my question, that's why I'm gonna give it a try here:
HOW Do I download a video (mp4) from an URL and store it within the app**
HOW Do I display the video then in a container**
I've already found this topic:
Swift - Downloading video with downloadTaskWithURL
But in my case, I wouldn't want the video to be safed in the camera-roll. Just within the app.
Thanks for any kind of help/hint !
You can use URLSession's dataTask or downloadTask to download any file from url(if it's downloadble)
Here's the way to use dataTask for downloading:
let videoUrl = "Some video url"
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let destinationUrl = docsUrl.appendingPathComponent("MyFileSaveName.mp4")
if(FileManager().fileExists(atPath: destinationUrl.path)){
print("\n\nfile already exists\n\n")
}
else{
//DispatchQueue.global(qos: .background).async {
var request = URLRequest(url: URL(string: videoUrl)!)
request.httpMethod = "GET"
_ = session.dataTask(with: request, completionHandler: { (data, response, error) in
if(error != nil){
print("\n\nsome error occured\n\n")
return
}
if let response = response as? HTTPURLResponse{
if response.statusCode == 200{
DispatchQueue.main.async {
if let data = data{
if let _ = try? data.write(to: destinationUrl, options: Data.WritingOptions.atomic){
print("\n\nurl data written\n\n")
}
else{
print("\n\nerror again\n\n")
}
}//end if let data
}//end dispatch main
}//end if let response.status
}
}).resume()
//}//end dispatch global
}//end outer else
Now to play the saved file:
class MyViewController: UIViewController {
override func viewDidLoad() {
let baseUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let assetUrl = baseUrl.appendingPathComponent("MyFileSaveName.mp4")
let url = assetUrl
print(url)
let avAssest = AVAsset(url: url)
let playerItem = AVPlayerItem(asset: avAssest)
let player = AVPlayer(playerItem: playerItem)
let playerViewController = AVPlayerViewController()
playerViewController.player = player
self.present(playerViewController, animated: true, completion: {
player.play()
})
}
}
However, most sites do not provide a direct dwonloadable link for video. You can get that link by playing the video in a UIWebView and register this following observer to get that link:
NotificationCenter.default.addObserver(self, selector: #selector(videoPlayedInWebView), name: NSNotification.Name(rawValue: "AVPlayerItemBecameCurrentNotification"), object: nil)
#objc func videoPlayedInWebView(aNotification: NSNotification) {
if let playerItem: AVPlayerItem = aNotification.object as? AVPlayerItem{
let asset: AVURLAsset = playerItem.asset as! AVURLAsset
var downloadebaleVideoUrl = asset.url
print(downloadebaleVideoUrl)
}
}
Here "downloadebaleVideoUrl" is the link that will be generated once the video plays in the webview.
If you have any questions, feel free to ask.
Note: This is will work only for sites that have mp4 files. 'HLS' streams won't be downloaded with this method. For that you can refer to this following answer:
https://stackoverflow.com/a/54493233/10758374
Edit: this works only with UIWebView and it won't work with WKWebView.
You need to create a local url, that will be a path in your app's file system and write the video's data into it.
func writeToFile(urlString: String) {
guard let videoUrl = URL(string: urlString) else {
return
}
do {
let videoData = try Data(contentsOf: videoUrl)
let fm = FileManager.default
guard let docUrl = fm.urls(for: .documentDirectory, in: .userDomainMask).first else {
print("Unable to reach the documents folder")
return false
}
let localUrl = docUrl.appendingPathComponent("test.mp4")
try videoData.write(to: localUrl)
} catch {
print("could not save data")
}
}
Keep in mind to always call this function in the background thread.

Swift background music delay

I'm trying to make background music loop seamlessly while having a part that doesn't loop, but there is a delay when switching the AVAudioPlayers. The delay happens when songA stops and songB starts.
Here is the code.
lazy var songA: AVAudioPlayer? = {
guard let url = Bundle.main.url(forResource: "A", withExtension: "wav") else {
return nil
}
do {
let player = try AVAudioPlayer(contentsOf: url)
let x = player
x.delegate=self
player.numberOfLoops = 0
player.prepareToPlay()
return player
} catch {
return nil
}
}()
lazy var songB: AVAudioPlayer? = {
guard let url = Bundle.main.url(forResource: "B", withExtension: "wav") else {
return nil
}
do {
let player = try AVAudioPlayer(contentsOf: url)
player.numberOfLoops = -1
player.prepareToPlay()
return player
} catch {
return nil
}
}()
func multiTrack(songA: AVAudioPlayer, songB: AVAudioPlayer) {
masterStop()
songA.play()
while songA.isPlaying==true {
if songA.isPlaying==false{
songB.play()
songA.stop()
songA.prepareToPlay()
}
}
songB.play()
songA.stop()
songA.prepareToPlay()
songA.currentTime=0
}