ios - Objective-C没有已知的选择器'playAtTime'的类方法

我正在尝试使用AVAudioPlayer和playAtTime在用户设置的时间对警报进行编程，当我使用此代码[AVAudioPlayer playAtTime:dateTimeString];尝试使其在用户设置的时间播放时，出现此错误no known class method for selector 'playAtTime'。我的其余代码如下

 #import "ViewController.h"

 @interface ViewController()
 {
      AVAudioPlayer *_myPlayer;
 }
@end

@implementation ViewController

 - (void)viewDidLoad
{
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.

NSString *path = [NSString stringWithFormat:@"%@/drum01.mp3", [[NSBundle mainBundle] resourcePath]];
NSURL *soundUrl = [NSURL fileURLWithPath:path];
_alarmPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundUrl error:nil];

}

-(IBAction) alarmSetButtonTapped:(id)sender {

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSString *dateTimeString = [dateFormatter stringFromDate: dateTimePicker.date ];
NSLog( @"Set button tapped : %@", dateTimeString );

[AVAudioPlayer playAtTime:dateTimeString];

[self scheduleLocalNotificationWithDate: dateTimePicker.date];

}

- (void)didReceiveMemoryWarning
{
  [super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end

还有viewcontroller.h

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

@interface ViewController : UIViewController <AVAudioPlayerDelegate>
  {
     IBOutlet UIDatePicker *dateTimePicker;
  }


 -(IBAction) alarmSetButtonTapped:(id)sender;

 @end

如何解决此错误并使用playAtTime？

谢谢

最佳答案

-[AVAudioPlayer playAtTime:]方法是实例方法，而不是类方法，因此必须在实例（例如_alarmPlayer）上调用它。此外，其参数是NSTimeInterval，而不是字符串。

无论如何，此方法都无法满足您的要求。它用于从播放器以外的其他位置启动播放器；参数表示应该从样本开始多远。它不会计划在将来的某个时间播放音频样本。

关于ios - Objective-C没有已知的选择器'playAtTime'的类方法，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32676517/