objective-c - 播放 iPod 库中的歌曲

Question

我正在尝试播放 iPod 库中的几首歌曲。我可以使用以下代码播放一首歌曲：

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];

当我添加到以前的代码时，它会播放一首歌曲“Poker Face”

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

[myArtistQuery addFilterPredicate:artist1]; 

它什么都不播放。我有一系列歌曲标题，如果它们存在，我想播放它们。

我怎样才能做到这一点？

谢谢你。

Answer 1

这是解决方案。播放艺术家 iPod 库中的两首歌曲

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];