Problems with AVAudioPlayer

问题

I'm new to the iPhone-Development.

I want to play a Sound when an UIButton is tapped. I tried the following:

ViewController.h:

@interface JahrenzeitenViewController : UIViewController <AVAudioPlayerDelegate> {

    UIButton *button_PlaySound;
    AVAudioPlayer *audioPlayer;
}

@property (nonatomic, retain) IBOutlet UIButton *button_PlaySound;

ViewController.m

- (IBAction)playSound {

    //[audioPlayer release];
    //audioPlayer = nil;

    NSString *audioFilePath = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"wav"];
    NSURL *audioFileURL = [NSURL fileURLWithPath:audioFilePath];
    NSError *error = nil;
    audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:audioFileURL error:&error];
    [audioPlayer setDelegate:self];
    [audioPlayer prepareToPlay];
    [audioPlayer play];
    if (audioPlayer == nil) 
        NSLog(@"Error playing sound. %@", [error description]);
    else
        [audioPlayer play];

If I try to run the App, I get the following error:

Undefined symbols for architecture i386: "_OBJC_CLASS_$_AVAudioPlayer", referenced from: objc-class-ref in JahrenzeitenViewController.o ld: symbol(s) not found for architecture i386 collect2: ld returned 1 exit status

I also tried to change the Line

audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:audioFileURL error:&error];

to

audioPlayer = [audioPlayer initWithContentsOfURL:audioFileURL error:&error];

Then I don't get the error above, but its still not playing and i get the DebugMessage from my NSLog in the "playSound"-Method:

Error playing sound. (NULL)

I hope you can help me. Thank you in advance :)

回答1:

You need to add the AVFoundation framework to your project. (right-click on your main target then add existing framework).

回答2:

To add to the other answers.

You should always look at the documentation of a class 'I.e AVAudioPlayer. That you are unfamiliar with when you intend to use it. There at the top of the documentation ( Class Reference) for the the Class, is a table showing what framework the class belongs to:

Once you know this add the framework to the project. And also import it into the header (.h) file as others have pointed out

回答3:

thank you, it worked. I didn't know that I have to add the Framework :S

I used the following instructions:

1. In the project navigator, select your project
2. Select your target
3. Select the 'Build Phases' tab
4. Open 'Link Binaries With Libraries' expander
5. Click the '+' button
6. Select your framework

回答4:

Pls add the AVFoundation framework to your project. And i think you should add <AVFoundation/AVFoundation.h> along with <AudioToolbox/AudioToolbox.h>

来源：https://stackoverflow.com/questions/5376437/problems-with-avaudioplayer