Basic queueing is functional

Audio Players/SMKAVQueuePlayer.m

@@ -30,7 +30,7 @@ @implementation SMKAVQueuePlayer {
 - (id)init
 {
     if ((self = [super init])) {
-        self.audioPlayer = [AVQueuePlayer queuePlayerWithItems:nil];
+        self.audioPlayer = [AVQueuePlayer queuePlayerWithItems:[NSArray array]];
         __weak SMKAVQueuePlayer *weakSelf = self;
         _timeObserver = [self.audioPlayer addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(1.f, 1.f) queue:NULL usingBlock:^(CMTime time) {
             SMKAVQueuePlayer *strongSelf = weakSelf;

Audio Players/SMKMPMusicPlayer.m

@@ -8,6 +8,8 @@
 
 #import "SMKMPMusicPlayer.h"
 #import "SMKMPMediaTrack.h"
+
+#import "SMKErrorCodes.h"
 #import "NSError+SMKAdditions.h"
 
 @interface SMKMPMusicPlayer ()
@@ -29,6 +31,7 @@ - (id)init
         [self.audioPlayer beginGeneratingPlaybackNotifications];
         self.audioPlayer.repeatMode = MPMusicRepeatModeNone;
         self.audioPlayer.shuffleMode = MPMusicShuffleModeOff;
+        self.seekTimeInterval = SMKPlayerDefaultSeekTimeInterval;
     }
     return self;
 }

Audio Players/SMKSpotifyPlayer.m

@@ -43,6 +43,9 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
             if (self.finishedTrackBlock)
                 self.finishedTrackBlock(self, self.oldCurrentTrack, nil);
             self.oldCurrentTrack = nil;
+            if (self.preloadedTrack) {
+                [self skipToPreloadedTrack];
+            }
         } else {
             self.preloadedTrack = nil;
         }
@@ -124,7 +127,8 @@ - (void)preloadTrack:(id<SMKTrack>)track completionHandler:(void(^)(NSError *err
 
 - (void)skipToPreloadedTrack
 {
-    [self playTrack:self.preloadedTrack completionHandler:nil];
+    if (self.preloadedTrack) 
+        [self playTrack:self.preloadedTrack completionHandler:nil];
 }
 
 #pragma mark - Accessors

Common Headers/SMKErrorCodes.h

@@ -9,7 +9,6 @@
 extern NSInteger const SMKPlayerErrorFailedToCreateInputSource;
 extern NSInteger const SMKPlayerErrorFailedToCreateDecoder;
 extern NSInteger const SMKPlayerErrorFailedToEnqueueTrack;
-extern NSInteger const SMKPlayerErrorTrackAlreadyPreloaded;
 extern NSInteger const SMKPlayerErrorItemAlreadyExists;
 
 extern NSInteger const SMKCoreDataErrorDataStoreNotAFolder;

Common Headers/SMKErrorCodes.m

@@ -11,6 +11,7 @@
 NSInteger const SMKPlayerErrorFailedToCreateInputSource     = 0;
 NSInteger const SMKPlayerErrorFailedToCreateDecoder         = 1;
 NSInteger const SMKPlayerErrorItemAlreadyExists             = 2;
+NSInteger const SMKPlayerErrorFailedToEnqueueTrack          = 3;
 
 NSInteger const SMKCoreDataErrorDataStoreNotAFolder         = 4;
 NSInteger const SMKCoreDataErrorFailedToInitializeStore     = 5;

Content Sources/MPMediaLibrary/Data Model/SMKMPMediaTrack.m

@@ -9,6 +9,8 @@
 #import "SMKMPMediaTrack.h"
 #import "SMKMPMediaAlbum.h"
 #import "SMKMPMediaHelpers.h"
+#import "SMKAVQueuePlayer.h"
+#import "SMKMPMusicPlayer.h"
 
 @interface SMKMPMediaAlbum (SMKInternal)
 - (id)initWithRepresentedObject:(MPMediaItem*)object contentSource:(id<SMKContentSource>)contentSource;
@@ -44,7 +46,7 @@ + (NSSet *)supportedSortKeys
 
 - (Class)playerClass
 {
-    return NSClassFromString((self.playbackURL != nil) ? @"SMKAVQueuePlayer" : @"SMKMPMusicPlayer");
+    return (self.playbackURL != nil) ? [SMKAVQueuePlayer class] : [SMKMPMusicPlayer class];
 }
 
 #pragma mark - SMKTrack

Example Apps/MPMediaLibraryExample/DetailViewController.h

@@ -13,4 +13,5 @@
 @property (strong, nonatomic) id detailItem;
 
 @property (weak, nonatomic) IBOutlet UILabel *detailDescriptionLabel;
+- (IBAction)seekForward:(id)sender;
 @end

Example Apps/MPMediaLibraryExample/DetailViewController.m

@@ -10,6 +10,7 @@
 #import "SNRMusicKitiOS.h"
 #import "SMKMPMediaContentSource.h"
 #import "SMKMPMusicPlayer.h"
+#import "SMKQueueController.h"
 
 @interface DetailViewController ()
 @property (strong, nonatomic) UIPopoverController *masterPopoverController;
@@ -18,7 +19,7 @@ - (void)configureView;
 @end
 
 @implementation DetailViewController {
-    SMKMPMusicPlayer *_player;
+    SMKQueueController *_controller;
 }
 
 #pragma mark - Managing the detail item
@@ -42,7 +43,6 @@ - (void)configureView
         strongSelf.tracks = tracks;
         [self.tableView reloadData];
     }];
-    _player = [SMKMPMusicPlayer new];
 }
 
 - (void)viewDidLoad
@@ -74,11 +74,10 @@ - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(N
 
 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
 {
-    SMKMPMediaTrack *object = self.tracks[indexPath.row];
-    NSLog(@"%@", [object playbackURL]);
-    [_player playTrack:object completionHandler:^(NSError *error) {
-        NSLog(@"%@", error);
-    }];
+    NSArray *array = [self.tracks subarrayWithRange:NSMakeRange(indexPath.row, [self.tracks count] - indexPath.row)];
+    NSLog(@"%@", array);
+    _controller = [SMKQueueController queueControllerWithTracks:array];
+    [_controller play:nil];
 }
 
 #pragma mark - Split view
@@ -97,4 +96,9 @@ - (void)splitViewController:(UISplitViewController *)splitController willShowVie
     self.masterPopoverController = nil;
 }
 
+- (IBAction)seekForward:(id)sender
+{
+    [_controller seekForward:nil];
+}
+
 @end

Example Apps/MPMediaLibraryExample/en.lproj/MainStoryboard_iPad.storyboard

@@ -56,7 +56,13 @@
                             <outlet property="delegate" destination="k1S-Fw-fPT" id="NJm-jj-izg"/>
                         </connections>
                     </tableView>
-                    <navigationItem key="navigationItem" title="Tracks" id="xYw-DX-WhN"/>
+                    <navigationItem key="navigationItem" title="Tracks" id="xYw-DX-WhN">
+                        <barButtonItem key="rightBarButtonItem" title="Seek Forward" id="df0-Kk-nhT">
+                            <connections>
+                                <action selector="seekForward:" destination="k1S-Fw-fPT" id="HfE-WB-NFW"/>
+                            </connections>
+                        </barButtonItem>
+                    </navigationItem>
                     <connections>
                         <outlet property="view" destination="jqB-za-Asj" id="yMr-mm-BhV"/>
                     </connections>
@@ -143,6 +149,7 @@
         <class className="DetailViewController" superclassName="UITableViewController">
             <source key="sourceIdentifier" type="project" relativePath="./Classes/DetailViewController.h"/>
             <relationships>
+                <relationship kind="action" name="seekForward:"/>
                 <relationship kind="outlet" name="detailDescriptionLabel" candidateClass="UILabel"/>
             </relationships>
         </class>

Master API/SMKQueueController.m

@@ -15,10 +15,10 @@ @interface SMKQueueItem : NSObject
 @interface SMKQueueController ()
 @property (nonatomic, strong) NSMutableArray *items;
 @property (nonatomic, strong, readwrite) id<SMKPlayer> currentPlayer;
+@property (nonatomic, assign, readwrite) NSUInteger indexOfCurrentTrack;
 @end
 
 @implementation SMKQueueController
-
 - (id)init
 {
     if ((self = [super init])) {
@@ -73,16 +73,6 @@ - (void)removeTrack:(id<SMKTrack>)track
 
 #pragma mark - Accessors
 
-- (NSUInteger)indexOfCurrentTrack
-{
-    return [self.items indexOfObject:self.currentTrack];
-}
-
-+ (NSSet *)keyPathsForValuesAffectingIndexOfCurrentTrack
-{
-    return [NSSet setWithObject:@"currentTrack"];
-}
-
 - (NSTimeInterval)playbackTime
 {
     return [self.currentPlayer playbackTime];
@@ -177,7 +167,15 @@ - (IBAction)playPause:(id)sender
 
 - (IBAction)next:(id)sender
 {
-
+    if ([[self.currentPlayer class] supportsPreloading] && [self.currentPlayer preloadedTrack]) {
+        [self.currentPlayer skipToPreloadedTrack];
+        self.indexOfCurrentTrack++;
+    } else {
+        NSUInteger nextIndex = self.indexOfCurrentTrack + 1;
+        if (nextIndex < [self countOfItems])
+            [self _beginPlayingItemAtIndex:nextIndex];
+    }
+    [self _recalculateIndexOfCurrentTrack];
 }
 
 - (IBAction)previous:(id)sender
@@ -187,12 +185,12 @@ - (IBAction)previous:(id)sender
 
 - (IBAction)seekForward:(id)sender
 {
-
+    [self.currentPlayer seekForward];
 }
 
 - (IBAction)seekBackward:(id)sender
 {
-
+    [self.currentPlayer seekBackward];
 }
 
 #pragma mark - Private
@@ -223,17 +221,33 @@ - (NSUInteger)_indexOfTrack:(id<SMKTrack>)track
 - (void)_beginPlayingItemAtIndex:(NSUInteger)index
 {
     id<SMKTrack> track = [[self.items objectAtIndex:index] track];
-    self.currentPlayer = [[track playerClass] new];
+    id<SMKPlayer> player = [[track playerClass] new];
+    NSLog(@"now playing %@ with %@", [track name], player);
+    self.currentPlayer = player;
     __weak SMKQueueController *weakSelf = self;
-    [self.currentPlayer playTrack:track completionHandler:^(NSError *error) {
+    [player playTrack:track completionHandler:^(NSError *error) {
+        SMKQueueController *strongSelf = weakSelf;
         if (error) {
-            SMKQueueController *strongSelf = weakSelf;
             SMKGenericErrorLog([NSString stringWithFormat:@"Error playing track %@", track], error);
             [strongSelf removeObjectFromItemsAtIndex:index];
             strongSelf.currentPlayer = nil;
-            if (index < [self.items count])
-                [self _beginPlayingItemAtIndex:index];
+            if (index < [strongSelf countOfItems])
+                [strongSelf _beginPlayingItemAtIndex:index];
+        } else {
+            [strongSelf _recalculateIndexOfCurrentTrack];
         }
     }];
+    [player setFinishedTrackBlock:^(id<SMKPlayer> player, id<SMKTrack> track, NSError *error) {
+        SMKQueueController *strongSelf = weakSelf;
+        [strongSelf next:nil];
+    }];
 }
+
+- (void)_recalculateIndexOfCurrentTrack
+{
+    self.indexOfCurrentTrack = [self _indexOfTrack:self.currentTrack];
+}
+@end
+
+@implementation SMKQueueItem
 @end

SNRMusicKit.xcodeproj/project.pbxproj

@@ -118,6 +118,8 @@
 		036994CF15E3F3EB003BCCBE /* UIImageView+AFNetworking.m in Sources */ = {isa = PBXBuildFile; fileRef = 036994A615E3F3EB003BCCBE /* UIImageView+AFNetworking.m */; settings = {COMPILER_FLAGS = "-fno-objc-arc"; }; };
 		036994D015E3F461003BCCBE /* CoreData.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 036991F615E3EAE1003BCCBE /* CoreData.framework */; };
 		036994D215E3F475003BCCBE /* CoreData.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 036994D115E3F475003BCCBE /* CoreData.framework */; };
+		036F857515EEC45100DF72B9 /* SMKQueueController.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = 0371CF9915EDECF200B304CC /* SMKQueueController.h */; };
+		036F857615EEC54500DF72B9 /* SMKAVQueuePlayer.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = 03FBEC9D15E6E0C100A67DEE /* SMKAVQueuePlayer.h */; };
 		0370109C15E5535500FEAF6F /* SMKiTunesSyncOperation.h in Headers */ = {isa = PBXBuildFile; fileRef = 0370109A15E5535500FEAF6F /* SMKiTunesSyncOperation.h */; };
 		0370109D15E5535500FEAF6F /* SMKiTunesSyncOperation.m in Sources */ = {isa = PBXBuildFile; fileRef = 0370109B15E5535500FEAF6F /* SMKiTunesSyncOperation.m */; };
 		037010A015E5630000FEAF6F /* SMKiTunesConstants.h in Headers */ = {isa = PBXBuildFile; fileRef = 0370109E15E5630000FEAF6F /* SMKiTunesConstants.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -403,6 +405,8 @@
 				0306DB6B15EC199800D6409B /* SMKMPMediaTrack.h in CopyFiles */,
 				0371CF9515EDE47700B304CC /* SMKMPMediaAlbum.h in CopyFiles */,
 				0371CF9315EDE44C00B304CC /* SMKMPMusicPlayer.h in CopyFiles */,
+				036F857515EEC45100DF72B9 /* SMKQueueController.h in CopyFiles */,
+				036F857615EEC54500DF72B9 /* SMKAVQueuePlayer.h in CopyFiles */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};