Question

嗨，我有一个应用程序，你必须按住一个按钮，吹进手机，它发出声音，这是代码：

      #import "AirInstrumentViewController.h"

@implementation AirInstrumentViewController
    @synthesize audiOfA;
       - (void)didReceiveMemoryWarning
      {
/ / Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.
}

   #pragma mark - View lifecycle



       - (void)viewDidLoad
  {
     [super viewDidLoad];


     NSURL *url = [NSURL fileURLWithPath:@"/dev/null"];

NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
                          [NSNumber numberWithFloat: 44100.0],                 AVSampleRateKey,
                          [NSNumber numberWithInt: kAudioFormatAppleLossless], AVFormatIDKey,
                          [NSNumber numberWithInt: 1],                         AVNumberOfChannelsKey,
                          [NSNumber numberWithInt: AVAudioQualityMax],         AVEncoderAudioQualityKey,
                          nil];

NSError *error;

recorder = [[AVAudioRecorder alloc] initWithURL:url settings:settings error:&error];

if (recorder) {
    [recorder prepareToRecord];
    recorder.meteringEnabled = YES;
    [recorder record];
    levelTimer = [NSTimer scheduledTimerWithTimeInterval: 0.03 target: self selector: @selector(levelTimerCallback:) userInfo: nil repeats: YES];
} else
    NSLog([error description]); 
}

          -  (void)levelTimerCallback:(NSTimer *)timer {
[recorder updateMeters];

const double ALPHA = 0.05;
double peakPowerForChannel = pow(10, (0.05 * [recorder peakPowerForChannel:0]));
lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults;  

if (lowPassResults > 0.55) {
    NSLog(@"Mic blow detected");

    if (aIsBeingTouched == YES) {
        NSString *musicString = [[NSBundle mainBundle] pathForResource:@"A" ofType:@"aifc"];
        audiOfA = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:musicString] error:NULL];
        [audiOfA play];

    } }else {

        [audiOfA stop];
    }


}

   -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {


UITouch *touch = [[event allTouches] anyObject];

CGPoint touchLocation = [touch locationInView:self.view];
if (CGRectContainsPoint(aImage.frame, touchLocation)) {

    aImage.image = [UIImage imageNamed:@"active.png"];
    aIsBeingTouched = YES;

          }
         }
             -(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
 [audiOfA stop];

aImage.image = [UIImage imageNamed:@"a.png"];

aIsBeingTouched = NO;

     }

- (void)viewDidUnload
     {

[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
   }



    @end

我希望你明白我想做什么。在这里： if（lowPassResults＆gt; 0.55）{ NSLog（@“麦克风检测”）;

if (aIsBeingTouched == YES) {
    NSString *musicString = [[NSBundle mainBundle] pathForResource:@"A" ofType:@"aifc"];
    audiOfA = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:musicString] error:NULL];
    [audiOfA play];

} }else {

    [audiOfA stop];
}


  }

声音持续时间更长，然后停止。触摸结束时也一样。如果我吹虽然没有按住图像，但是当我最终按住图像时，即使我没有吹也会播放，因为当它没有被按下时它被吹了，它可能已经记录了它或者有些东西！我不知道如何解决所有这些问题，请帮忙！

Answer 1

NSTimer是非常不可靠的。根据{{3}}，引用：

定时器的时间间隔的有效分辨率限制在50-100毫秒的量级

可能是因为你如此快速地调用它们（0.03秒或30毫秒非常快），NSTimer没有按照确切的间隔进行调用，因此它正在跳过。

您可能希望尝试多线程处理，以便与UI相关的所有内容在主线程上完成，AVAudio部分在单独的线程上完成。 Apple Documentation是一个解释NSOperation的链接，这是一种简单的方法，并且鉴于您提供的代码，它应该适合您。

希望有帮助！

立刻停止音乐

1 个答案: