Objective c 网络类没有'；t将数据发送给学员目标C

我是Objective-C新手，我正在尝试创建一个类来处理应用程序的

URLSession

任务，以便从

SoundCloud

下载和播放歌曲，并使用

协议和委托将其传递给
SongPlayer
类

我的NetworkManager.h文件：

#import <Foundation/Foundation.h>

@protocol NetworkDelegateProtocol<NSObject>
-(void) didReceiveData:(id) data;
@end

@interface NetworkManager : NSObject

@property (nonatomic, weak) id<NetworkDelegateProtocol>delegate;
-(void) requestSong: (NSString *) songUrlStr;

@end

#import <UIKit/UIKit.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>

#import "NetworkManager.h"

@interface SongPlayer : NSObject <NetworkDelegateProtocol ,AVAudioPlayerDelegate>

@property NetworkManager *networkManager;

@property (nonatomic, weak) AVAudioPlayer *songPlayer;
@property (nonatomic, weak) NSData *songData;

@property BOOL didDownload;

@end

我的SongPlayer.h文件：

#import <Foundation/Foundation.h>

@protocol NetworkDelegateProtocol<NSObject>
-(void) didReceiveData:(id) data;
@end

@interface NetworkManager : NSObject

@property (nonatomic, weak) id<NetworkDelegateProtocol>delegate;
-(void) requestSong: (NSString *) songUrlStr;

@end

#import <UIKit/UIKit.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>

#import "NetworkManager.h"

@interface SongPlayer : NSObject <NetworkDelegateProtocol ,AVAudioPlayerDelegate>

@property NetworkManager *networkManager;

@property (nonatomic, weak) AVAudioPlayer *songPlayer;
@property (nonatomic, weak) NSData *songData;

@property BOOL didDownload;

@end

我在
songplayervewcontroller
类中将
SongPlayer
类设置为
Delegate
：

@implementation SongPlayerViewController {

    SongPlayer *songPlayer;
}

- (void)viewDidLoad {
    [super viewDidLoad];

songPlayer = [[SongPlayer alloc]init];

    songPlayer.networkManager.delegate = songPlayer;
NSArray *songUrlArray = [[NSArray alloc] initWithObjects: baseSongUrlStr, songId, endSongUrlStr, nil];
NSString *requestUrl = [songUrlArray componentsJoinedByString:@""];
NetworkManager *network = [[NetworkManager alloc] init];
[self setupSong];

[network requestSong:requestUrl];

}
@结束

当我尝试调试它时，
dataTaskWithURL
已完成，
NetworkManager
类接收
数据
，但它从未将其发送给
委托

先谢谢你

注：在我的
NetworkManager
课程中，我有另一个
URLSession
任务来按名称获取歌曲列表，该任务非常有效。
在设置代理时，您的
SongPlayer
上的
NetworkManager
属性可能为零，因此。。。在Objective-C中，什么都没有发生

@implementation SongPlayerViewController {

    SongPlayer *songPlayer;

...

- (void)viewDidLoad {
    [super viewDidLoad];

    songPlayer = [[SongPlayer alloc]init];
    NetworkManager *network = [[NetworkManager alloc] init];   // do this here
    songPlayer.networkManager = network;                       // set before use
    songPlayer.networkManager.delegate = songPlayer;

    NSArray *songUrlArray = [[NSArray alloc] initWithObjects: baseSongUrlStr, songId, endSongUrlStr, nil];
    NSString *requestUrl = [songUrlArray componentsJoinedByString:@""];
    [self setupSong];

    [network requestSong:requestUrl];
} 
@end

正如他在评论中所建议的，我必须更改songPlayer.networkManager.delegate=songPlayer；to network.delegate=songPlayer；在视图控制器和它的工作！
再次感谢。
你在哪里调用requestSong？我的错误，我在SongPlayerServiceController类的viewDidLoad中调用requestSong，刚刚编辑了文章。谢谢。你在哪里初始化SongPlayer？呃，在同一个地方（SongPlayServiceWController类中的viewDidLoad），你的方法签名是错误的-（无效）didReceiveData：（id）数据；应该是id而不是NSData。