一站式音樂立即

Question

嗨，我有一個應用程序，你必須按下一個按鈕後吹至手機併發出聲音，這裏是代碼：

 #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 

我希望你明白我想去做。在此處： 如果（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]; 
} 


    } 

聲音持續時間更長，然後停止。相同的觸摸結束。如果我在拍下圖像的同時擊倒 ，那麼當我最終把圖像放下時，即使我沒有吹，因爲我在沒有按下時發出聲音，它可能會記錄下它或者有些東西！我不知道如何解決所有這些問題，請幫助！

Answer 1

NSTimer是非常不可靠的。按照Apple Documentation，報價：

的計時器的時間間隔的有效分辨率被限制在50-100毫秒

的順序

這可能是因爲你在呼喚他們，所以很快（0.03秒或30毫秒非常快），NSTimer沒有在確切的時間間隔被調用，因此它正在跳過。

您可能需要嘗試多線程處理，以便在主線程上完成與UI相關的所有操作，並且AVAudio部分在單獨的線程上完成。 This是一個解釋NSOperation的鏈接，這是一個簡單的方法來完成此操作，並且根據您提供的代碼應該適合您。

希望有助於！