从iPod库播放歌曲

Question

我试图播放iPod库中的几首歌曲。我可以使用此代码播放一首歌曲：

MPMusicPlayerController *musicPlayer = [MPMusicPlayerController applicationMusicPlayer]; 
MPMediaPropertyPredicate *artist = [MPMediaPropertyPredicate predicateWithValue:@"Poker Face" forProperty:MPMediaItemPropertyTitle]; 

MPMediaQuery *myArtistQuery = [[MPMediaQuery alloc] init]; 
[myArtistQuery addFilterPredicate:artist]; 

[musicPlayer setQueueWithQuery:myArtistQuery]; 
[musicPlayer play]; 

它起着一个歌曲“扑克脸”，当我加入到以前的代码

MPMediaPropertyPredicate *artist1 = [MPMediaPropertyPredicate predicateWithValue:@"Born This Way" forProperty:MPMediaItemPropertyTitle] 

[myArtistQuery addFilterPredicate:artist1]; 

它起着什么。我有一些歌曲标题，如果它们存在，我想播放它们。

我该怎么做？

谢谢。

Answer 1

这里是解决方案。从播放的iPod库两首歌曲的艺术家

 

MPMusicPlayerController *musicPlayer = [MPMusicPlayerController applicationMusicPlayer]; 
MPMediaQuery *everything = [[MPMediaQuery alloc] init]; 

MPMediaPropertyPredicate *artist = [MPMediaPropertyPredicate predicateWithValue:@"AC/DC" forProperty:MPMediaItemPropertyArtist]; 
[everything addFilterPredicate:artist]; 
NSArray *itemsFromGenericQuery = [everything items]; 

NSMutableArray *array = [[NSMutableArray alloc] init]; 
for (MPMediaItem *song in itemsFromGenericQuery) { 
    NSString *songTitle = [song valueForProperty: MPMediaItemPropertyTitle]; 
    if ([songTitle isEqualToString:@"Highway to Hell"]) { 
     NSLog (@"%@", songTitle); 
     [array addObject:song]; 
    } 
    if ([songTitle isEqualToString:@"Thunderstruck"]) { 
     NSLog (@"%@", songTitle); 
     [array addObject:song]; 
    } 

} 

MPMediaItemCollection *collection = [[MPMediaItemCollection alloc] initWithItems:array]; 
[musicPlayer setQueueWithItemCollection:collection]; 
// NSLog(@"%@", [[MPMediaQuery songsQuery].items); 
[musicPlayer play];