IOS，得到浮球液位麦克风updateMesters当麦克风被录制音频

Question

这里是我记录的代码现在通过示例UIlable浮点数怎样才能在麦克风水平声音输入

我想我会使用这个功能，但如何能我用这个在rec.h & rec.m文件

（无效）updateMeters

AVAudioSession * audioSession = [AVAudioSession sharedInstance]; 
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil]; 
[audioSession setActive:YES error:nil]; 
NSMutableDictionary* recordSetting = [[NSMutableDictionary alloc] init]; 
[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey]; 
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; 
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey]; 
recordedTmpName = [[NSString alloc] initWithFormat:@"%.0f.%@", [NSDate timeIntervalSinceReferenceDate] * 1000.0, @"aac"]; 
temporaryRecFile= [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:recordedTmpName]]; 
recorder = [[ AVAudioRecorder alloc] initWithURL:temporaryRecFile settings:recordSetting error:nil]; 
[recorder setDelegate:self]; 
[recorder prepareToRecord]; 
[recorder record]; 

Answer 1

在录制过程中，你必须定期调用updateMeters，和0123得到的平均功率- （浮点）averagePowerForChannel：（NSUInteger）广告channelNumber

[recorder setDelegate:self]; 
[recorder prepareToRecord]; 
recorder.meteringEnabled = YES; 
[recorder record]; 
NSTimer* timer = [NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(handleTimer) userInfo:nil repeats:YES]; 




- (void) handleTimer 
{ 
    [recorder updateMeters]; 
    label.text = [NSString stringWithFormat:@"lf",[recorder averagePowerForChannel:0]]; 
} 

要了解更多信息，请访问AVAudioRecorder Class Reference