#import 
     
      #import 
      
       @interface ViewController : UIViewController
       
        @property (weak, nonatomic) IBOutlet UILabel *infoLabel;@property (weak, nonatomic) IBOutlet UISlider *volumeSlider;@property (weak, nonatomic) IBOutlet UIButton *playButton;@property (weak, nonatomic) IBOutlet UITextField *artistTextField;@property (strong, nonatomic) MPMediaItemCollection *myCollection;@property (strong, nonatomic) MPMusicPlayerController *player;- (IBAction)addItems:(id)sender;- (IBAction)prevTapped:(id)sender;- (IBAction)playTapped:(id)sender;- (IBAction)nextTapped:(id)sender;- (IBAction)updateVolume:(id)sender;- (IBAction)queueMusicByArtist:(id)sender;@end
       
      
     

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController@synthesize infoLabel;@synthesize volumeSlider;@synthesize playButton;@synthesize artistTextField;- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.    self.infoLabel.text = @"...";        self.player = [MPMusicPlayerController applicationMusicPlayer];        [self setNotifications];        [self.player beginGeneratingPlaybackNotifications];        [self.player setShuffleMode:MPMusicShuffleModeOff];    self.player.repeatMode = MPMusicRepeatModeNone;        self.volumeSlider.value = self.player.volume;        self.artistTextField.delegate = self;    self.artistTextField.enablesReturnKeyAutomatically = YES;}-(void)setNotifications{    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];        [notificationCenter     addObserver: self     selector:    @selector(handleNowPlayingItemChanged:)     name:        MPMusicPlayerControllerNowPlayingItemDidChangeNotification     object:      self.player];        [notificationCenter     addObserver: self     selector:    @selector(handlePlaybackStateChanged:)     name:        MPMusicPlayerControllerPlaybackStateDidChangeNotification     object:      self.player];        [notificationCenter     addObserver: self     selector:    @selector(handleVolumeChangedFromHardware:)     name:        @"AVSystemController_SystemVolumeDidChangeNotification"     object:      nil];}-(void)handleVolumeChangedFromHardware:(id)sender{    [self.volumeSlider setValue:self.player.volume animated:YES];}- (void) handlePlaybackStateChanged: (id) notification{    MPMusicPlaybackState playbackState = [self.player playbackState];        if (playbackState == MPMusicPlaybackStateStopped)    {        [self.playButton setTitle:@"Play" forState:UIControlStateNormal];    }    else if (playbackState == MPMusicPlaybackStatePaused)    {        [self.playButton setTitle:@"Play" forState:UIControlStateNormal];    }    else if (playbackState == MPMusicPlaybackStatePlaying)    {        [self.playButton setTitle:@"Pause" forState:UIControlStateNormal];    }}- (void) handleNowPlayingItemChanged: (id) notification{    MPMediaItem *currentItemPlaying = [self.player nowPlayingItem];    if (currentItemPlaying)    {        NSString *info = [NSString stringWithFormat:@"%@ - %@", [currentItemPlaying valueForProperty:MPMediaItemPropertyTitle], [currentItemPlaying valueForProperty:MPMediaItemPropertyArtist]];        self.infoLabel.text = info;    }    else    {        self.infoLabel.text = @"...";    }}-(void)mediaPickerDidCancel:(MPMediaPickerController *)mediaPicker{    [self dismissViewControllerAnimated:YES completion:NULL];}-(void)mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection{    [self updateQueueWithMediaItemCollection:mediaItemCollection];    [self dismissViewControllerAnimated:YES completion:NULL];}-(void)updateQueueWithMediaItemCollection:(MPMediaItemCollection *)collection{    if (collection)    {        if (self.myCollection == nil)        {            self.myCollection = collection;            [self.player setQueueWithItemCollection: self.myCollection];            [self.player play];        }        else        {            BOOL wasPlaying = NO;            if (self.player.playbackState == MPMusicPlaybackStatePlaying)            {                wasPlaying = YES;            }                        MPMediaItem *nowPlayingItem        = self.player.nowPlayingItem;            NSTimeInterval currentPlaybackTime = self.player.currentPlaybackTime;                        NSMutableArray *combinedMediaItems =            [[self.myCollection items] mutableCopy];            NSArray *newMediaItems = [collection items];            [combinedMediaItems addObjectsFromArray: newMediaItems];                        self.myCollection = [MPMediaItemCollection collectionWithItems:combinedMediaItems];                        [self.player setQueueWithItemCollection:self.myCollection];                        self.player.nowPlayingItem      = nowPlayingItem;            self.player.currentPlaybackTime = currentPlaybackTime;                        if (wasPlaying)            {                [self.player play];            }        }    }}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (IBAction)addItems:(id)sender{    MPMediaPickerController *picker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];    picker.delegate = self;    picker.allowsPickingMultipleItems = YES;    picker.prompt =    NSLocalizedString (@"Add songs to play",                       "Prompt in media item picker");    [self presentViewController:picker animated:YES completion:NULL];}- (IBAction)prevTapped:(id)sender{    if ([self.player currentPlaybackTime] > 5.0)    {        [self.player skipToBeginning];    }    else    {        [self.player skipToPreviousItem];    }}- (IBAction)playTapped:(id)sender{    if ((self.myCollection != nil) && (self.player.playbackState != MPMusicPlaybackStatePlaying))    {        [self.player play];        [self.playButton setTitle:@"Pause" forState:UIControlStateNormal];    }    else if (self.player.playbackState == MPMusicPlaybackStatePlaying)    {        [self.player pause];        [self.playButton setTitle:@"Play" forState:UIControlStateNormal];    }}- (IBAction)nextTapped:(id)sender{    [self.player skipToNextItem];}- (IBAction)updateVolume:(id)sender{    self.player.volume = self.volumeSlider.value;}- (IBAction)queueMusicByArtist:(id)sender{    NSString *artist = self.artistTextField.text;    if (artist != nil && artist != @"")    {        MPMediaPropertyPredicate *artistPredicate = [MPMediaPropertyPredicate predicateWithValue:artist forProperty:MPMediaItemPropertyArtist comparisonType:MPMediaPredicateComparisonContains];        MPMediaQuery *query = [[MPMediaQuery alloc] init];        [query addFilterPredicate:artistPredicate];                NSArray *result = [query items];        if ([result count] > 0)        {            [self updateQueueWithMediaItemCollection:[MPMediaItemCollection collectionWithItems:result]];        }        else            self.infoLabel.text = @"Artist Not Found.";    }}-(BOOL)textFieldShouldReturn:(UITextField *)textField{    [textField resignFirstResponder];    [self queueMusicByArtist:self];    return NO;}