IOS - 移动到单独的类(class)时播放 mp3 失败

Question

我在类里面成功地播放了一个 mp3 文件。但是，当我将功能移出到单独的类时，它失败了。

这是工作代码:

标题:

#import <AVFoundation/AVFoundation.h>

@interface QuestionController : UIViewController 
<UITableViewDataSource, UITableViewDelegate, UISplitViewControllerDelegate>
{
    AVAudioPlayer *audioPlayer;

}

工作代码:

NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/A.mp3", [[NSBundle mainBundle] resourcePath]]];

    NSError *error;
    audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
    audioPlayer.numberOfLoops = 0;

    if (audioPlayer == nil)
        NSLog(@"audio errror: %@",[error description]);             
    else 
        [audioPlayer play];

这是新类(class):

标题:

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>


    @interface AudioPlayer : NSObject {

    }

    - (void *) playAudioFile:(NSString *) mp3File;

    @end

实现:

  #import "AudioPlayer.h"

    @implementation AudioPlayer

    - (void *) playAudioFile:(NSString *) mp3File {

        NSLog(@"mp3file to play: %@", mp3File ); 

        NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@", mp3File, [[NSBundle mainBundle] resourcePath]]];

        NSError *error;

        AVAudioPlayer *audioPlayer;
        audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
        audioPlayer.numberOfLoops = 0;

        if (audioPlayer == nil) {
            NSLog(@"audio errror: %@",[error description]);
        }
        else {
            [audioPlayer play];
        }
        [audioPlayer release];

        return 0; 
    }   

    @end

调用代码如下:

   AudioPlayer *audioPlayer = [[AudioPlayer alloc] init];

   [audioPlayer playAudioFile:@"/A.mp3"];

但是，当它在单独的类中运行时，它没有成功创建播放器并转到“audio player == nil”分支

这是输出:

012-07-21 07:14:54.480 MyQuiz[6655:207] mp3file to play: /A.mp3
2012-07-21 07:15:40.827 MyQuiz[6655:207] audio errror: Error Domain=NSOSStatusErrorDomain Code=-43 "The operation couldn’t be completed. (OSStatus error -43.)"

网址是“file://localhost/A.mp3”

知道我做错了什么吗？当我重构为单独的方法时，我总是遇到麻烦。真令人沮丧。

Answer 1

您的网址有误，请更改此行

NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@", mp3File, [[NSBundle mainBundle] resourcePath]]];

为此:

NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@%@", [[NSBundle mainBundle] resourcePath], mp3File]];