IOS。我不能播放调用 NSObject 类的 mp3，但是它可以直接从 UIViewController 工作

我可以直接在 ViewController 中使用 AVAudioPlayer 框架播放 mp3 文件作为按钮的操作，但是如果我想播放相同的 mp3 调用 NSObject 类中的选择器，则失败。谢谢你的建议。

从 ViewController (audioPlayerDemo.xcodeproj) 播放 mp3 并且可以正常工作:

框架文件夹中包含的 AVFoundation.framework

APDViewController.h

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

    @interface APDViewController : UIViewController <AVAudioPlayerDelegate>
    {
    }
    @property (strong,nonatomic) AVAudioPlayer *audioPlay;

    - (IBAction)playid)sender;

APDViewController.m

    @implementation APDViewController

    @synthesize audioPlay;

    - (IBAction)playid)sender
    {
        NSError *error = nil;
        NSData *dataAudio = [[NSData alloc] initWithContentsOfFile:
           @"/Users/User/Documents/AudioPlayerDemo/AudioPlayerDemo/hello world.mp3"options:0 error:&error];
        if(error){
            NSLog(@" error loading data: %@ ", [error localizedDescription]);
        }
        else{
            audioPlay = [[AVAudioPlayer alloc] initWithData:dataAudio error:&error];
            if(error){
                NSLog(@" error loading audio: %@ ", [error localizedDescription]);
            }
            else{
                audioPlay.delegate = self;
                [audioPlay prepareToPlay];
                [audioPlay play];
            }
        } 
    }

    -(void)audioPlayerDidFinishPlaying:
    (AVAudioPlayer *)player successfullyBOOL)flag
    {
        if (player == audioPlay){
            audioPlay = nil;
            NSLog(@"audioplay = nil");
        }
    }

但是，如果我想播放调用 NSObject 类 (AudioPlayClass.xcodeproj) 的相同 .mp3，则没有错误，也没有任何声音。这里的代码不起作用:

框架文件夹中包含的 AVFoundation.framework

APCplayObject.h

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

    @interface APCplayObject : NSObject <AVAudioPlayerDelegate>
    {
    }
    @property (strong,nonatomic) AVAudioPlayer *audioPlay;

    - (void)playAudio;

    @end

APCplayObject.m

    #import "APCplayObject.h"
    @implementation APCplayObject

    @synthesize audioPlay;

    -(void)playAudio{

        NSError *error = nil;
        NSData *dataAudio = [[NSData alloc] initWithContentsOfFile:
           @"/Users/User/Documents/AudioPlayerClass/AudioPlayerClass/hello world.mp3"options:0 error:&error];
        if(error){
            NSLog(@" error loading data: %@ ", [error localizedDescription]);
        }
        else{
            audioPlay = [[AVAudioPlayer alloc] initWithData:dataAudio error:&error];
            if(error){
                NSLog(@" error loading audio: %@ ", [error localizedDescription]);
            }
            else{
                audioPlay.delegate = self;
                [audioPlay prepareToPlay];
                [audioPlay play];
            }
        }
    }

    -(void)audioPlayerDidFinishPlaying:
    (AVAudioPlayer *)player successfullyBOOL)flag  
    {
        if (player == audioPlay){
            audioPlay = nil;
            NSLog(@"audioplay = nil");
        }
    }

APCviewController.m，调用者作为一个按钮的 Action :

    - (IBAction)callPlayid)sender {
        APCplayObject *a = [[APCplayObject alloc] init];
        [a playAudio];

    }

提前致谢。

---

Best Answer-推荐答案

问题是在你开始播放音频后，变量a超出了范围，因此被销毁了。

当方法退出时，您需要创建一个声明的属性来保存您的 APCplayObject。

所以，在 APCviewController.h 中你可以这样做:

@property (strong,nonatomic) APCplayObject *playObject;

然后将 callPlay 改为:

- (IBAction)callPlayid)sender {
    if (!self.playObject)  // Use this line if you only want to create one playObject, take it out to create a new one every time.
        self.playObject = [[APCplayObject alloc] init];
    [self.playObject playAudio];

}

关于IOS。我不能播放调用 NSObject 类的 mp3，但是它可以直接从 UIViewController 工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17584728/