Soundcloud应用程序如何快速跳到下一首曲目？(How does Soundcloud app skip to next track so fast?)

我正在构建我的第一个应用程序，它是一个Soundcloud客户端。现在，每次选择播放曲目时，我都必须继续进行NSURLSessionDataTask获取以获取二进制数据，但这需要很长时间。当我跳到下一首曲目时，我必须在播放当前歌曲时提前输入逻辑以下载下一首歌曲...但是，如果用户快速跳过，这仍然很慢：/

Soundcloud本机应用程序立即跳过。它是如何工作的？我尝试过使用Soundcloud iOS SDK，但现在已弃用。

这是我的歌曲获取：

-(void)fetchTrack: (SCTrack*)selectedTrack completionHandler: (void(^)(NSData *trackData, NSString *error)) completionHandler; { NSString* clientID = @"41a5278fd8c704c3eb5a4a0ca38f9036"; NSString* streamURL = selectedTrack.stream_url; NSString* urlString = [NSString stringWithFormat:@"%@?client_id=%@", streamURL, clientID]; NSURL* url = [[NSURL alloc]initWithString:urlString]; NSLog(@"%@", urlString); NSMutableURLRequest* request = [[NSMutableURLRequest alloc]initWithURL:url]; request.HTTPMethod = @"GET"; NSURLSessionDataTask* dataTask = [[self session] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { NSHTTPURLResponse* callResponse = (NSHTTPURLResponse*)response; if ([callResponse isKindOfClass:[NSHTTPURLResponse class]]) { NSInteger responseCode = [callResponse statusCode]; if (responseCode >= 200 && responseCode <= 299) { NSData* trackData = data; NSLog(@"STREAM 200"); [[NSOperationQueue mainQueue]addOperationWithBlock:^{ NSLog(@"%@", data); completionHandler(trackData, nil); }]; }else{ NSLog(@"%ld", (long)responseCode); } } }]; [dataTask resume]; }

这就是我正在播放并尝试在当前曲目播放时获取下一首歌曲的方式：

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { self.selectedTrack = self.SCTrackList[indexPath.row]; self.selectedTrackRow = indexPath.row; [[SoundCloudAPI sharedInstance]fetchTrack:self.selectedTrack completionHandler:^(NSData *trackData, NSString *error) { self.player = [[AVAudioPlayer alloc]initWithData: trackData error:nil]; [self.player prepareToPlay]; [self.player play];; }]; [self prepareForNextTrack:self.selectedTrack]; } -(void)prepareForNextTrack: (SCTrack*)trackPlaying { self.selectedTrackRow += 1; self.selectedTrack = self.SCTrackList[self.selectedTrackRow]; [[SoundCloudAPI sharedInstance]fetchTrack:self.selectedTrack completionHandler:^(NSData *trackData, NSString *error) { self.trackDataToPlay = trackData; }]; } - (IBAction)nextPressed:(id)sender { self.player = [[AVAudioPlayer alloc]initWithData: self.trackDataToPlay error:nil]; [self.player prepareToPlay]; [self.player play];; [self prepareForNextTrack:self.selectedTrack]; }

另外，我是新手，所以我确信我的代码非常笨重，如果有人能指出改进的方法，我会很感激。

谢谢你指出了正确的方向！

I'm building my first app and it's a Soundcloud client. Right now, everytime a track is selected to play, I have to go on and do a NSURLSessionDataTask fetch to get the binary data, but this takes a long time. And when I skip, to the next track, I have to add the logic in to download the next song ahead of time when the current song is playing...though, this is still slow if the user skips quickly:/

The Soundcloud native app skips instantly. How do it work? I've tried using Soundcloud iOS SDK but it is now deprecated.

Here is my song fetch:

-(void)fetchTrack: (SCTrack*)selectedTrack completionHandler: (void(^)(NSData *trackData, NSString *error)) completionHandler; { NSString* clientID = @"41a5278fd8c704c3eb5a4a0ca38f9036"; NSString* streamURL = selectedTrack.stream_url; NSString* urlString = [NSString stringWithFormat:@"%@?client_id=%@", streamURL, clientID]; NSURL* url = [[NSURL alloc]initWithString:urlString]; NSLog(@"%@", urlString); NSMutableURLRequest* request = [[NSMutableURLRequest alloc]initWithURL:url]; request.HTTPMethod = @"GET"; NSURLSessionDataTask* dataTask = [[self session] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { NSHTTPURLResponse* callResponse = (NSHTTPURLResponse*)response; if ([callResponse isKindOfClass:[NSHTTPURLResponse class]]) { NSInteger responseCode = [callResponse statusCode]; if (responseCode >= 200 && responseCode <= 299) { NSData* trackData = data; NSLog(@"STREAM 200"); [[NSOperationQueue mainQueue]addOperationWithBlock:^{ NSLog(@"%@", data); completionHandler(trackData, nil); }]; }else{ NSLog(@"%ld", (long)responseCode); } } }]; [dataTask resume]; }

This is how I'm playing and attempting to fetch the next song while the current track is playing:

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { self.selectedTrack = self.SCTrackList[indexPath.row]; self.selectedTrackRow = indexPath.row; [[SoundCloudAPI sharedInstance]fetchTrack:self.selectedTrack completionHandler:^(NSData *trackData, NSString *error) { self.player = [[AVAudioPlayer alloc]initWithData: trackData error:nil]; [self.player prepareToPlay]; [self.player play];; }]; [self prepareForNextTrack:self.selectedTrack]; } -(void)prepareForNextTrack: (SCTrack*)trackPlaying { self.selectedTrackRow += 1; self.selectedTrack = self.SCTrackList[self.selectedTrackRow]; [[SoundCloudAPI sharedInstance]fetchTrack:self.selectedTrack completionHandler:^(NSData *trackData, NSString *error) { self.trackDataToPlay = trackData; }]; } - (IBAction)nextPressed:(id)sender { self.player = [[AVAudioPlayer alloc]initWithData: self.trackDataToPlay error:nil]; [self.player prepareToPlay]; [self.player play];; [self prepareForNextTrack:self.selectedTrack]; }

Also, I'm new, so I'm sure my code is pretty clunky and would appreciated if anyone can point out ways to improve.

Thanks for pointing in the right direction!

最满意答案

因此，我变得比以往更复杂。我所要做的就是使用dataWithContentsOfURL方法来检索在令牌中传递的歌曲。

NSData *data =[NSData dataWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@?oauth_token=%@",self.selectedTrack.stream_url, self.token]]];

当然，将数据放在AVAudioPlayer中。

基本上，摆脱我上面的fetchTrack函数。

So it turns I made things wayyyy more complicated than had to be. All I had to do was the dataWithContentsOfURL method to go retrieve the song passing in the token.

NSData *data =[NSData dataWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@?oauth_token=%@",self.selectedTrack.stream_url, self.token]]];

And of course, put the data in the AVAudioPlayer.

Basically, getting rid of my fetchTrack function above.

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