使用AudioServicesAddSystemSoundCompletion时尝试从声音回调函数中隐藏按钮时出错 [英] Error when trying to hide a button from a sound callback function when using AudioServicesAddSystemSoundCompletion

问题描述

我正在尝试使用声音回调函数在声音文件完成播放后显示一个按钮.

 //定义回调AudioServicesAddSystemSoundCompletion(soundID，NULL，NULL，AudioPlaybackComplete，self.nextButton)； 

这是回调函数:

 静态void AudioPlaybackComplete(SystemSoundID ssID，void * clientData) 

{

  NSLog(@显示这些织补按钮");AudioServicesRemoveSystemSoundCompletion(ssID);//显示按钮，以便您可以切换到下一个动物[nextButton setHidden:YES]; 

}

我已将nextButton定义为头文件中的插座，并已正确引用.当 [nextButton setHidden:YES]; 尝试执行时，出现以下错误:"错误:'nextButton'未声明(此功能首次使用)".

我相信，因为这是一个静态函数，所以在引用此文件的实例变量时遇到了问题.关于如何使该方法不是静态的，或者使它正确引用按钮的任何想法?

谢谢

解决方案

我知道了.诀窍是将按钮传递给回调函数.

 //定义回调AudioServicesAddSystemSoundCompletion(soundID，NULL，NULL，AudioPlaybackComplete，self.nextButton)； 

然后是回调函数本身

 静态void AudioPlaybackComplete(SystemSoundID ssID，void * button){NSLog(@显示那些织补按钮");AudioServicesRemoveSystemSoundCompletion(ssID);//显示按钮，以便您可以切换到下一个动物[button setHidden:NO];} 

I'm trying to use a sound callback function to show a button once my sound file completes playing.

//defining the callback
AudioServicesAddSystemSoundCompletion (soundID, NULL, NULL, AudioPlaybackComplete, self.nextButton);

Here's the callback function:

static void AudioPlaybackComplete(SystemSoundID  ssID, void *clientData)

{

NSLog(@"Show those darn buttons");
AudioServicesRemoveSystemSoundCompletion (ssID);

//show the buttons so you can switch to the next animal
[nextButton setHidden:YES];

}

I've got nextButton defined as an outlet in the header file and referenced properly. I get the following error when the [nextButton setHidden:YES]; tries to execute: "error: 'nextButton' undeclared (first use in this function)".

I believe because this is a static function it's having problems referencing the instance variable form this file. Any thoughts on how I can have this method not be static, or have it reference the button properly?

Thanks

解决方案

Ah I figured it out. The trick was to pass in the button to the callback function.

    //defining the callback    
    AudioServicesAddSystemSoundCompletion (soundID, NULL, NULL, AudioPlaybackComplete, self.nextButton);

And then the callback function itself

static void AudioPlaybackComplete(SystemSoundID  ssID, void *button)
    {
        NSLog(@"Show those darn buttons");
        AudioServicesRemoveSystemSoundCompletion (ssID);

        //show the buttons so you can switch to the next animal
        [button setHidden:NO];
    }

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