-(void)Eduqu{     NSError *err=nil;     NSString *str=[NSStringstringWithFormat:@"http://127.0.0.1/audio/upload/%d.aif",I];     NSURL *fileUrl=[NSURL URLWithString:str];     NSData *data=[NSData dataWithContentsOfURL:fileUrl];     //設定後台播放     [[AVAudioSessionsharedInstance]setCategory:AVAudioSessionCategoryPlaybackerror:&err];     //設定激活狀態     [[AVAudioSession sharedInstance]setActive:YES error:&err];     //播放     player=[[AVAudioPlayer alloc]initWithData:data error:&err];          [player play];   }