Video in background

Stepic/Info.plist

@@ -2,8 +2,6 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-	<key>UIStatusBarStyle</key>
-	<string>UIStatusBarStyleLightContent</string>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>en</string>
 	<key>CFBundleExecutable</key>
@@ -89,6 +87,10 @@
 		<key>NSAllowsArbitraryLoads</key>
 		<true/>
 	</dict>
+	<key>UIBackgroundModes</key>
+	<array>
+		<string>audio</string>
+	</array>
 	<key>UILaunchStoryboardName</key>
 	<string>LaunchScreen</string>
 	<key>UIMainStoryboardFile</key>
@@ -97,6 +99,8 @@
 	<array>
 		<string>armv7</string>
 	</array>
+	<key>UIStatusBarStyle</key>
+	<string>UIStatusBarStyleLightContent</string>
 	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>

Stepic/Player.swift

@@ -293,6 +293,15 @@ public class Player: UIViewController {
     public override func viewDidLoad() {
         super.viewDidLoad()
 
+        if RemoteConfig.shared.allowVideoInBackground {
+            do {
+                try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
+                try AVAudioSession.sharedInstance().setActive(true)
+            } catch {
+                print("failed to set up background playing: \(error)")
+            }
+        }
+
         self.playerView.layer.addObserver(self, forKeyPath: PlayerReadyForDisplayKey, options: ([.new, .old]), context: &PlayerLayerObserverContext)
         self.timeObserver = self.avplayer.addPeriodicTimeObserver(forInterval: CMTimeMake(1, 100), queue: DispatchQueue.main, using: { [weak self] _ in
             guard let strongSelf = self else { return }
@@ -468,28 +477,41 @@ extension Player {
     // UIApplication
 
     internal func addApplicationObservers() {
-        NotificationCenter.default.addObserver(self, selector: #selector(applicationWillResignActive(_:)), name: NSNotification.Name.UIApplicationWillResignActive, object: UIApplication.shared)
-        NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackground(_:)), name: NSNotification.Name.UIApplicationDidEnterBackground, object: UIApplication.shared)
-        NotificationCenter.default.addObserver(self, selector: #selector(applicationWillEnterForeground(_:)), name: NSNotification.Name.UIApplicationWillEnterForeground, object: UIApplication.shared)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationWillResignActive(_:)), name: .UIApplicationWillResignActive, object: UIApplication.shared)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationDidBecomeActive(_:)), name: .UIApplicationDidBecomeActive, object: UIApplication.shared)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationDidEnterBackground(_:)), name: .UIApplicationDidEnterBackground, object: UIApplication.shared)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationWillEnterForeground(_:)), name: .UIApplicationWillEnterForeground, object: UIApplication.shared)
     }
 
     internal func removeApplicationObservers() {
     }
 
-    @objc internal func applicationWillResignActive(_ aNotification: NSNotification) {
-        if self.playbackState == .playing {
+    @objc internal func handleApplicationWillResignActive(_ aNotification: Notification) {
+        if !RemoteConfig.shared.allowVideoInBackground && self.playbackState == .playing {
             self.pause()
         }
     }
 
-    @objc internal func applicationDidEnterBackground(_ aNotification: NSNotification) {
-        if self.playbackState == .playing {
-            self.pause()
+    @objc internal func handleApplicationDidBecomeActive(_ aNotification: Notification) {
+        if RemoteConfig.shared.allowVideoInBackground {
+            // Attach AVPlayer to AVPlayerLayer again
+            playerView.player = self.avplayer
+        }
+    }
+
+    @objc internal func handleApplicationDidEnterBackground(_ aNotification: Notification) {
+        if RemoteConfig.shared.allowVideoInBackground {
+            // Detach AVPlayer from AVPlayerLayer (from Apple's manual)
+            playerView.player = nil
+        } else {
+            if self.playbackState == .playing {
+                self.pause()
+            }
         }
     }
 
-    @objc internal func applicationWillEnterForeground(_ aNoticiation: NSNotification) {
-        if self.playbackState == .paused {
+    @objc internal func handleApplicationWillEnterForeground(_ aNoticiation: Notification) {
+        if !RemoteConfig.shared.allowVideoInBackground && self.playbackState == .paused {
             self.playFromCurrentTime()
         }
     }
@@ -622,21 +644,17 @@ extension Player {
 
 internal class PlayerView: UIView {
 
-    var player: AVPlayer! {
+    var player: AVPlayer? {
         get {
-            return (self.layer as! AVPlayerLayer).player
+            return playerLayer.player
         }
         set {
-            if (self.layer as! AVPlayerLayer).player != newValue {
-                (self.layer as! AVPlayerLayer).player = newValue
-            }
+            playerLayer.player = newValue
         }
     }
 
     var playerLayer: AVPlayerLayer {
-        get {
-            return self.layer as! AVPlayerLayer
-        }
+        return layer as! AVPlayerLayer
     }
 
     var fillMode: String {

Stepic/RemoteConfig.swift

@@ -13,10 +13,12 @@ enum RemoteConfigKeys: String {
     case showStreaksNotificationTrigger = "show_streaks_notification_trigger"
     case adaptiveBackendUrl = "adaptive_backend_url"
     case supportedInAdaptiveModeCourses = "adaptive_courses_ios"
+    case allowVideoInBackground = "allow_video_in_background"
 }
 
 class RemoteConfig {
     private let defaultShowStreaksNotificationTrigger = ShowStreaksNotificationTrigger.loginAndSubmission
+    private let defaultAllowVideoInBackground = false
     static let shared = RemoteConfig()
 
     var loadingDoneCallback: (() -> Void)?
@@ -25,7 +27,8 @@ class RemoteConfig {
     lazy var appDefaults: [String: NSObject] = [
         RemoteConfigKeys.showStreaksNotificationTrigger.rawValue: defaultShowStreaksNotificationTrigger.rawValue as NSObject,
         RemoteConfigKeys.adaptiveBackendUrl.rawValue: StepicApplicationsInfo.adaptiveRatingURL as NSObject,
-        RemoteConfigKeys.supportedInAdaptiveModeCourses.rawValue: StepicApplicationsInfo.adaptiveSupportedCourses as NSObject
+        RemoteConfigKeys.supportedInAdaptiveModeCourses.rawValue: StepicApplicationsInfo.adaptiveSupportedCourses as NSObject,
+        RemoteConfigKeys.allowVideoInBackground.rawValue: defaultAllowVideoInBackground as NSObject
     ]
 
     enum ShowStreaksNotificationTrigger: String {
@@ -57,6 +60,14 @@ class RemoteConfig {
         return ids
     }
 
+    var allowVideoInBackground: Bool {
+        guard let configValue = FirebaseRemoteConfig.RemoteConfig.remoteConfig().configValue(forKey: RemoteConfigKeys.allowVideoInBackground.rawValue).stringValue else {
+            return defaultAllowVideoInBackground
+        }
+
+        return configValue == "true"
+    }
+
     init() {
         loadDefaultValues()
         fetchCloudValues()

Stepic/StepicVideoPlayerViewController.swift

@@ -230,6 +230,7 @@ class StepicVideoPlayerViewController: UIViewController {
     fileprivate var player: Player!
 
     var video: Video!
+    var videoInBackgroundTooltip: Tooltip?
 
     override func viewDidLoad() {
         super.viewDidLoad()
@@ -238,6 +239,8 @@ class StepicVideoPlayerViewController: UIViewController {
         WatchSessionSender.sendPlaybackStatus(.available)
 
         NotificationCenter.default.addObserver(self, selector: #selector(StepicVideoPlayerViewController.audioRouteChanged(_:)), name: NSNotification.Name.AVAudioSessionRouteChange, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationDidBecomeActive(_:)), name: .UIApplicationDidBecomeActive, object: UIApplication.shared)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleApplicationDidEnterBackground(_:)), name: .UIApplicationDidEnterBackground, object: UIApplication.shared)
 
         topTimeSlider.setThumbImage(Images.playerControls.timeSliderThumb, for: UIControlState())
 
@@ -275,7 +278,34 @@ class StepicVideoPlayerViewController: UIViewController {
         topTimeSlider.addTarget(self, action: #selector(StepicVideoPlayerViewController.finishedSeeking), for: UIControlEvents.touchUpInside)
         topTimeSlider.addTarget(self, action: #selector(StepicVideoPlayerViewController.startedSeeking), for: UIControlEvents.touchDown)
         MPRemoteCommandCenter.shared().togglePlayPauseCommand.addTarget(self, action: #selector(StepicVideoPlayerViewController.togglePlayPause))
-//        MPRemoteCommandCenter.sharedCommandCenter().togglePlayPauseCommand.addTarget(self, action: #selector(togglePlayStop(_:)));
+    }
+
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+
+        if RemoteConfig.shared.allowVideoInBackground && TooltipDefaultsManager.shared.shouldShowInVideoPlayer {
+            delay(2.0) { [weak self] in
+                guard let s = self else {
+                    return
+                }
+
+                s.videoInBackgroundTooltip = TooltipFactory.videoInBackground
+                s.videoInBackgroundTooltip?.show(direction: .down, in: s.view, from: s.fullscreenPlayButton, isArrowVisible: false)
+                TooltipDefaultsManager.shared.didShowInVideoPlayer = true
+            }
+        }
+    }
+
+    @objc internal func handleApplicationDidEnterBackground(_ aNotification: Notification) {
+        if !RemoteConfig.shared.allowVideoInBackground {
+            MPRemoteCommandCenter.shared().togglePlayPauseCommand.removeTarget(self)
+        }
+    }
+
+    @objc internal func handleApplicationDidBecomeActive(_ aNotification: Notification) {
+        if !RemoteConfig.shared.allowVideoInBackground {
+            MPRemoteCommandCenter.shared().togglePlayPauseCommand.addTarget(self, action: #selector(StepicVideoPlayerViewController.togglePlayPause))
+        }
     }
 
     @objc func togglePlayPause() {
@@ -389,9 +419,14 @@ class StepicVideoPlayerViewController: UIViewController {
 
 extension StepicVideoPlayerViewController : PlayerDelegate {
     func playerReady(_ player: Player) {
+        guard player.playbackState == .stopped else {
+            return
+        }
+
         print("player is ready to display")
         activityIndicator.isHidden = true
         setTimeParametersAfterPlayerIsReady()
+
         player.seekToTime(CMTime(seconds: playerStartTime, preferredTimescale: 1000))
         player.playFromCurrentTime()
         player.rate = currentRate.rawValue

Stepic/Tooltip.swift

@@ -12,6 +12,7 @@ import EasyTipView
 protocol Tooltip {
     init(text: String, shouldDismissAfterTime: Bool, color: TooltipColor)
     func show(direction: TooltipDirection, in inView: UIView?, from fromView: UIView)
+    func show(direction: TooltipDirection, in inView: UIView?, from fromView: UIView, isArrowVisible: Bool)
     func show(direction: TooltipDirection, in inView: UIView?, from fromItem: UIBarButtonItem)
     func dismiss()
 }
@@ -85,8 +86,18 @@ class EasyTipTooltip: Tooltip {
         preferences.drawing.borderColor = color.borderColor
     }
 
-    private func setupTooltip(direction: TooltipDirection) {
+    private func setupTooltip(direction: TooltipDirection, isArrowVisible: Bool) {
         preferences.drawing.arrowPosition = easyTipDirectionFromTooltipDirection(direction: direction)
+
+        if !isArrowVisible {
+            switch direction {
+            case .up, .down:
+                preferences.drawing.arrowWidth = CGFloat(0)
+            case .left, .right:
+                preferences.drawing.arrowHeight = CGFloat(0)
+            }
+        }
+
         easyTip = EasyTipView(text: text, preferences: preferences, delegate: nil)
     }
 
@@ -101,13 +112,17 @@ class EasyTipTooltip: Tooltip {
     }
 
     func show(direction: TooltipDirection, in inView: UIView?, from fromView: UIView) {
-        setupTooltip(direction: direction)
+        show(direction: direction, in: inView, from: fromView, isArrowVisible: true)
+    }
+
+    func show(direction: TooltipDirection, in inView: UIView?, from fromView: UIView, isArrowVisible: Bool) {
+        setupTooltip(direction: direction, isArrowVisible: isArrowVisible)
         easyTip.show(forView: fromView, withinSuperview: inView)
         setupDisappear()
     }
 
     func show(direction: TooltipDirection, in inView: UIView?, from fromItem: UIBarButtonItem) {
-        setupTooltip(direction: direction)
+        setupTooltip(direction: direction, isArrowVisible: true)
         easyTip.show(forItem: fromItem, withinSuperView: inView)
         setupDisappear()
     }

Stepic/TooltipDefaultsManager.swift

@@ -17,6 +17,7 @@ class TooltipDefaultsManager {
     private let didShowOnLessonDownloadsKey = "didShowOnLessonDownloadsKey"
     private let didShowOnHomeContinueLearningKey = "didShowOnHomeContinueLearningKey"
     private let didShowOnStreaksSwitchInProfileKey = "didShowOnStreaksSwitchInProfileKey"
+    private let didShowInVideoPlayerKey = "didShowInVideoPlayerKey"
 
     var didShowOnLessonDownloads: Bool {
         set(value) {
@@ -48,6 +49,16 @@ class TooltipDefaultsManager {
         }
     }
 
+    var didShowInVideoPlayer: Bool {
+        set(value) {
+            defaults.set(value, forKey: didShowInVideoPlayerKey)
+        }
+
+        get {
+            return defaults.value(forKey: didShowInVideoPlayerKey) as? Bool ?? false
+        }
+    }
+
     var shouldShowOnHomeContinueLearning: Bool {
         return !didShowOnHomeContinueLearning
     }
@@ -59,4 +70,8 @@ class TooltipDefaultsManager {
     var shouldShowOnStreaksSwitchInProfile: Bool {
         return !didShowOnStreaksSwitchInProfile
     }
+
+    var shouldShowInVideoPlayer: Bool {
+        return !didShowInVideoPlayer
+    }
 }

Stepic/TooltipFactory.swift

@@ -24,4 +24,8 @@ struct TooltipFactory {
     static var streaksTooltip: Tooltip {
         return EasyTipTooltip(text: NSLocalizedString("StreaksSwitchTooltip", comment: ""), shouldDismissAfterTime: true, color: .standard)
     }
+
+    static var videoInBackground: Tooltip {
+        return EasyTipTooltip(text: NSLocalizedString("VideoInBackgroundTooltip", comment: ""), shouldDismissAfterTime: true, color: .standard)
+    }
 }

Stepic/en.lproj/Localizable.strings

@@ -400,6 +400,7 @@ ShareCourseTooltip = "Share the link with your friends to learn together";
 LessonDownloadTooltip = "Download lesson to watch lectures offline";
 ContinueLearningWidgetTooltip = "Tap to continue from where you finished last time";
 StreaksSwitchTooltip = "Turn on to get new portion of knowledge every day";
+VideoInBackgroundTooltip = "You can play video in background";
 
 /* Notification alerts */
 NotificationTabNotificationRequestAlertTitle = "Stay tuned";

Stepic/ru.lproj/Localizable.strings

@@ -401,6 +401,7 @@ ShareCourseTooltip = "Поделитесь ссылкой с друзьями, 
 LessonDownloadTooltip = "Загрузите урок, чтобы смотреть видео оффлайн";
 ContinueLearningWidgetTooltip = "Нажмите, чтобы перейти к тому месту, где закончили в прошлый раз";
 StreaksSwitchTooltip = "Включите, чтобы получать новую порцию знаний каждый день";
+VideoInBackgroundTooltip = "Вы можете продолжить воспроизведение видео в фоновом режиме";
 
 /* Notification alerts */
 NotificationTabNotificationRequestAlertTitle = "Следи за обновлениями";