What is the reason of an index to be out of range and how to fix this issue in my code? - swift

Question

This is audio player, It worked fine before I started to try stream audios from firebase. Now data is downloaded from the firebase database, the image, title and subtitle are being displayed correctly, but when user taps on the cell the audio doesn't play and it throws a fatal error, Thread 1: Fatal error: Index out of range
This is a table view controller which lists the audio tracks from firebase database.
import UIKit
import AVKit
import AVFoundation
import FirebaseFirestore
import Combine
import SDWebImage
class ListOfAudioLessonsTableViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet var table: UITableView!
let placeHolderImage = UIImage(named: "placeHolderImage")
private var cancellable: AnyCancellable?
private var viewModel = AudiosViewModel()
var paragraphs = [Audio]()
override func viewDidLoad() {
super.viewDidLoad()
self.viewModel.fetchData()
self.title = "Audio Lessons"
table.delegate = self
table.dataSource = self
cancellable = viewModel.$audios.sink { _ in
DispatchQueue.main.async{
self.table.reloadData()
}
} // Do any additional setup after loading the view.
}
// Table
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("audios count = ", viewModel.audios.count)
return viewModel.audios.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
let audio = viewModel.audios[indexPath.row]
tableView.tableFooterView = UIView()
cell.textLabel?.text = audio.albumName
cell.detailTextLabel?.text = audio.name
cell.accessoryType = .disclosureIndicator
let imageURL = audio.audioImageName
cell.imageView?.sd_imageIndicator = SDWebImageActivityIndicator.gray
cell.imageView?.sd_setImage(with: URL(string: imageURL),
placeholderImage: placeHolderImage,
options: SDWebImageOptions.highPriority,
context: nil,
progress: nil,
completed: { downloadedImage, downloadException, cacheType, downloadURL in
if let downloadException = downloadException {
print("error downloading the image: \(downloadException.localizedDescription)")
} else {
print("successfuly downloaded the image: \(String(describing: downloadURL?.absoluteString))")
}
})
cell.textLabel?.numberOfLines = 0
cell.detailTextLabel?.numberOfLines = 0
let backgroundView = UIView()
backgroundView.backgroundColor = UIColor(named: "AudioLessonsCellHighlighted")
cell.selectedBackgroundView = backgroundView
cell.textLabel?.font = UIFont(name: "Helvetica-Bold", size: 14)
cell.detailTextLabel?.font = UIFont(name: "Helvetica", size: 12)
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 100
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
// present the player
let position = indexPath.row
//lessons
guard let vc = storyboard?.instantiateViewController(identifier: "AudioPlayer") as? AudioPlayerViewController else {
return
}
vc.paragraphs = paragraphs
vc.position = position
present(vc, animated: true)
}
func tableView(_ tableView: UITableView, didHighlightRowAt indexPath: IndexPath) {
if let cell = tableView.cellForRow(at: indexPath) {
cell.contentView.backgroundColor = UIColor(named: "AudioLessonsHighlighted")
cell.textLabel?.highlightedTextColor = UIColor(named: "textHighlighted")
cell.detailTextLabel?.highlightedTextColor = UIColor(named: "textHighlighted")
}
}
func tableView(_ tableView: UITableView, didUnhighlightRowAt indexPath: IndexPath) {
if let cell = tableView.cellForRow(at: indexPath) {
cell.contentView.backgroundColor = nil
}
}
}
import UIKit
import AVFoundation
import MediaPlayer
import AVKit
class AudioPlayerViewController: UIViewController {
public var position: Int = 0
public var paragraphs: [Audio] = []
#IBOutlet var holder: UIView!
var player: AVPlayer?
var playerItem: AVPlayerItem?
var isSeekInProgress = false
var chaseTime = CMTime.zero
fileprivate let seekDuration: Float64 = 15
var playerCurrentItemStatus: AVPlayerItem.Status = .unknown
// User Interface elements
private let albumImageView: UIImageView = {
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFill
return imageView
}()
private let paragraphNumberLabel: UILabel = {
let label = UILabel()
label.textAlignment = .left
label.font = .systemFont(ofSize: 16, weight: .light)
label.numberOfLines = 0 // allow line wrap
label.textColor = UIColor(named: "PlayerColors")
return label
}()
private let albumNameLabel: UILabel = {
let label = UILabel()
label.textAlignment = .left
label.font = .systemFont(ofSize: 18, weight: .bold)
label.numberOfLines = 0 // allow line wrap
label.textColor = UIColor(named: "PlayerColors")
return label
}()
private let songNameLabel: UILabel = {
let label = UILabel()
label.textAlignment = .left
label.font = .systemFont(ofSize: 16, weight: .ultraLight)
label.numberOfLines = 0 // allow line wrap
label.textColor = UIColor(named: "PlayerColors")
return label
}()
private let elapsedTimeLabel: UILabel = {
let label = UILabel()
label.textAlignment = .left
label.font = .systemFont(ofSize: 12, weight: .light)
label.textColor = UIColor(named: "PlayerColors")
label.text = "00:00"
label.numberOfLines = 0
return label
}()
private let remainingTimeLabel: UILabel = {
let label = UILabel()
label.textAlignment = .left
label.font = .systemFont(ofSize: 12, weight: .light)
label.textColor = UIColor(named: "PlayerColors")
label.text = "00:00"
label.numberOfLines = 0
return label
}()
private let playbackSlider: UISlider = {
let v = UISlider()
v.addTarget(AudioPlayerViewController.self, action: #selector(progressScrubbed(_:)), for: .valueChanged)
v.minimumTrackTintColor = UIColor.lightGray
v.maximumTrackTintColor = UIColor.darkGray
v.thumbTintColor = UIColor(named: "PlayerColors")
v.minimumValue = 0
v.isContinuous = true
return v
}()
let playPauseButton = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(panGesture(gesture:)))
self.playbackSlider.addGestureRecognizer(panGesture)
let audioSession = AVAudioSession.sharedInstance()
do {
try audioSession.setCategory(AVAudioSession.Category.playback)
}
catch{
print(error)
}
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
if holder.subviews.count == 0 {
configure()
}
}
func configure() {
// set up player
let song = paragraphs[position]
let url = URL(string: song.trackURL)
let playerItem: AVPlayerItem = AVPlayerItem(url: url!)
do {
try AVAudioSession.sharedInstance().setMode(.default)
try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
guard url != nil else {
print("urls string is nil")
return
}
player = AVPlayer(playerItem: playerItem)
let duration : CMTime = playerItem.asset.duration
let seconds : Float64 = CMTimeGetSeconds(duration)
remainingTimeLabel.text = self.stringFromTimeInterval(interval: seconds)
let currentDuration : CMTime = playerItem.currentTime()
let currentSeconds : Float64 = CMTimeGetSeconds(currentDuration)
elapsedTimeLabel.text = self.stringFromTimeInterval(interval: currentSeconds)
playbackSlider.maximumValue = Float(seconds)
player!.addPeriodicTimeObserver(forInterval: CMTimeMakeWithSeconds(1, preferredTimescale: 1), queue: DispatchQueue.main) { (CMTime) -> Void in
if self.player!.currentItem?.status == .readyToPlay {
let time : Float64 = CMTimeGetSeconds(self.player!.currentTime());
self.playbackSlider.value = Float(time)
self.elapsedTimeLabel.text = self.stringFromTimeInterval(interval: time)
}
let playbackLikelyToKeepUp = self.player?.currentItem?.isPlaybackLikelyToKeepUp
if playbackLikelyToKeepUp == false{
print("IsBuffering")
self.playPauseButton.isHidden = true
} else {
// stop the activity indicator
print("Buffering completed")
self.playPauseButton.isHidden = false
}
}
playbackSlider.addTarget(self, action: #selector(AudioPlayerViewController.progressScrubbed(_:)), for: .valueChanged)
self.view.addSubview(playbackSlider)
//subroutine used to keep track of current location of time in audio file
guard let player = player else {
print("player is nil")
return
}
player.play()
}
catch {
print("error accured")
}
// set up user interface elements
//album cover
albumImageView.frame = CGRect(x: 20,
y: 20,
width: holder.frame.size.width - 40,
height: holder.frame.size.width - 40)
albumImageView.image = UIImage(named: song.audioImageName)
holder.addSubview(albumImageView)
//Labels Song name, album, artist
albumNameLabel.frame = CGRect(x: 20,
y: holder.frame.size.height - 300,
width: holder.frame.size.width - 40,
height: 20)
paragraphNumberLabel.frame = CGRect(x: 20,
y: holder.frame.size.height - 280,
width: holder.frame.size.width-40,
height: 20)
songNameLabel.frame = CGRect(x: 20,
y: holder.frame.size.height - 260,
width: holder.frame.size.width-40,
height: 20)
playbackSlider.frame = CGRect(x: 20,
y: holder.frame.size.height - 235,
width: holder.frame.size.width-40,
height: 40)
elapsedTimeLabel.frame = CGRect(x: 25,
y: holder.frame.size.height - 200,
width: holder.frame.size.width-40,
height: 15)
remainingTimeLabel.frame = CGRect(x: holder.frame.size.width-60,
y: holder.frame.size.height - 200,
width: holder.frame.size.width-20,
height: 15)
songNameLabel.text = song.name
albumNameLabel.text = song.albumName
paragraphNumberLabel.text = song.paragraphNumber
holder.addSubview(songNameLabel)
holder.addSubview(albumNameLabel)
holder.addSubview(paragraphNumberLabel)
holder.addSubview(elapsedTimeLabel)
holder.addSubview(remainingTimeLabel)
//Player controls
let nextButton = UIButton()
let backButton = UIButton()
let seekForwardButton = UIButton()
let seekBackwardButton = UIButton()
//frames of buttons
playPauseButton.frame = CGRect(x: (holder.frame.size.width - 40) / 2.0,
y: holder.frame.size.height - 172.5,
width: 40,
height: 40)
nextButton.frame = CGRect(x: holder.frame.size.width - 70,
y: holder.frame.size.height - 162.5,
width: 30,
height: 20)
backButton.frame = CGRect(x: 70 - 30,
y: holder.frame.size.height - 162.5,
width: 30,
height: 20)
seekForwardButton.frame = CGRect(x: holder.frame.size.width - 140,
y: holder.frame.size.height - 167.5,
width: 30,
height: 30)
seekBackwardButton.frame = CGRect(x: 110,
y: holder.frame.size.height - 167.5,
width: 30,
height: 30)
let volumeView = MPVolumeView(frame: CGRect(x: 20,
y: holder.frame.size.height - 80,
width: holder.frame.size.width-40,
height: 30))
holder.addSubview(volumeView)
//actions of buttons
playPauseButton.addTarget(self, action: #selector(didTapPlayPauseButton), for: .touchUpInside)
backButton.addTarget(self, action: #selector(didTapBackButton), for: .touchUpInside)
nextButton.addTarget(self, action: #selector(didTapNextButton), for: .touchUpInside)
seekForwardButton.addTarget(self, action: #selector(seekForwardButtonTapped), for: .touchUpInside)
seekBackwardButton.addTarget(self, action: #selector(seekBackwardButtonTapped), for: .touchUpInside)
//styling of buttons
playPauseButton.setBackgroundImage(UIImage(systemName: "pause.fill"), for: .normal)
nextButton.setBackgroundImage(UIImage(systemName: "forward.fill"), for: .normal)
backButton.setBackgroundImage(UIImage(systemName: "backward.fill"), for: .normal)
seekForwardButton.setBackgroundImage(UIImage(systemName: "goforward.15"), for: .normal)
seekBackwardButton.setBackgroundImage(UIImage(systemName: "gobackward.15"), for: .normal)
playPauseButton.tintColor = UIColor(named: "PlayerColors")
nextButton.tintColor = UIColor(named: "PlayerColors")
backButton.tintColor = UIColor(named: "PlayerColors")
seekForwardButton.tintColor = UIColor(named: "PlayerColors")
seekBackwardButton.tintColor = UIColor(named: "PlayerColors")
holder.addSubview(playPauseButton)
holder.addSubview(nextButton)
holder.addSubview(backButton)
holder.addSubview(seekForwardButton)
holder.addSubview(seekBackwardButton)
}
#objc func panGesture(gesture: UIPanGestureRecognizer) {
let currentPoint = gesture.location(in: playbackSlider)
let percentage = currentPoint.x/playbackSlider.bounds.size.width;
let delta = Float(percentage) * (playbackSlider.maximumValue - playbackSlider.minimumValue)
let value = playbackSlider.minimumValue + delta
playbackSlider.setValue(value, animated: true)
}
#objc func progressScrubbed(_ playbackSlider: UISlider!) {
let seconds : Int64 = Int64(playbackSlider.value)
let targetTime:CMTime = CMTimeMake(value: seconds, timescale: 1)
player!.seek(to: targetTime)
if player!.rate == 0
{
player?.play()
}
}
func setupNowPlaying() {
// Define Now Playing Info
var nowPlayingInfo = [String : Any]()
nowPlayingInfo[MPMediaItemPropertyTitle] = "Unstoppable"
if let image = UIImage(named: "artist") {
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { size in
return image
}
}
nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = player?.currentTime
nowPlayingInfo[MPMediaItemPropertyPlaybackDuration] = playerItem?.duration
nowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = player?.rate
// Set the metadata
MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}
func updateNowPlaying(isPause: Bool) {
// Define Now Playing Info
var nowPlayingInfo = MPNowPlayingInfoCenter.default().nowPlayingInfo!
nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = player?.currentTime
nowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = isPause ? 0 : 1
// Set the metadata
MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}
func setupNotifications() {
let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self,
selector: #selector(handleInterruption),
name: AVAudioSession.interruptionNotification,
object: nil)
notificationCenter.addObserver(self,
selector: #selector(handleRouteChange),
name: AVAudioSession.routeChangeNotification,
object: nil)
}
#objc func handleRouteChange(notification: Notification) {
guard let userInfo = notification.userInfo,
let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
let reason = AVAudioSession.RouteChangeReason(rawValue:reasonValue) else {
return
}
switch reason {
case .newDeviceAvailable:
let session = AVAudioSession.sharedInstance()
for output in session.currentRoute.outputs where output.portType == AVAudioSession.Port.headphones {
print("headphones connected")
DispatchQueue.main.sync {
player?.play()
}
break
}
case .oldDeviceUnavailable:
if let previousRoute =
userInfo[AVAudioSessionRouteChangePreviousRouteKey] as? AVAudioSessionRouteDescription {
for output in previousRoute.outputs where output.portType == AVAudioSession.Port.headphones {
print("headphones disconnected")
DispatchQueue.main.sync {
player?.pause()
}
break
}
}
default: ()
}
}
#objc func handleInterruption(notification: Notification) {
guard let userInfo = notification.userInfo,
let typeValue = userInfo[AVAudioSessionInterruptionTypeKey] as? UInt,
let type = AVAudioSession.InterruptionType(rawValue: typeValue) else {
return
}
if type == .began {
print("Interruption began")
// Interruption began, take appropriate actions
}
else if type == .ended {
if let optionsValue = userInfo[AVAudioSessionInterruptionOptionKey] as? UInt {
let options = AVAudioSession.InterruptionOptions(rawValue: optionsValue)
if options.contains(.shouldResume) {
// Interruption Ended - playback should resume
print("Interruption Ended - playback should resume")
player?.play()
} else {
// Interruption Ended - playback should NOT resume
print("Interruption Ended - playback should NOT resume")
}
}
}
}
#objc func didTapPlayPauseButton() {
if player?.timeControlStatus == .playing {
//pause
player?.pause()
//show play button
playPauseButton.setBackgroundImage(UIImage(systemName: "play.fill"), for: .normal)
//shrink image
UIView.animate(withDuration: 0.2, animations: {
self.albumImageView.frame = CGRect(x: 50,
y: 50,
width: self.holder.frame.size.width - 100,
height: self.holder.frame.size.width - 100)
})
}
else {
//play
player?.play()
//show pause button
playPauseButton.setBackgroundImage(UIImage(systemName: "pause.fill"), for: .normal)
//increase image size
UIView.animate(withDuration: 0.4, animations: {
self.albumImageView.frame = CGRect(x: 20,
y: 20,
width: self.holder.frame.size.width - 40,
height: self.holder.frame.size.width - 40)
})
}
}
private func setupView() {
setupConstraints()
}
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
player?.play()
UIApplication.shared.isIdleTimerDisabled = true
}
override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
player?.pause()
UIApplication.shared.isIdleTimerDisabled = false
}
}
AudioViewModel
import Foundation
import FirebaseFirestore
class AudiosViewModel: ObservableObject {
#Published var audios = [Audio]()
private var db = Firestore.firestore()
func fetchData() {
db.collection("audios").addSnapshotListener { [self] (querySnapshot, error) in
guard let documents = querySnapshot?.documents else {
print("No Documents")
return
}
self.audios = documents.map { (queryDocumentSnapshot) -> Audio in
let data = queryDocumentSnapshot.data()
let name = data["name"] as? String ?? ""
let albumName = data["albumName"] as? String ?? ""
let audioImageName = data["audioImageName"] as? String ?? ""
let paragraphNumber = data["paragraphNumber"] as? String ?? ""
let trackURL = data["trackURL"] as? String ?? ""
print(data)
return Audio(name: name, albumName: albumName, paragraphNumber: paragraphNumber, audioImageName: audioImageName, trackURL: trackURL)
}
}
}
}
Audio Structure
import Foundation
struct Audio {
let name: String
let albumName: String
let paragraphNumber: String
let audioImageName: String
let trackURL: String
}

Answer 1

Assign/append value to your paragraphs and also check your position if there will be no values/wrong position it'll throw index out of range