IPhone之AVAudioRecorder

#import <AVFoundation/AVFoundation.h>  需要引入

//获取document目录的路径
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    - (NSString*) documentsPath {  
     if (! _documentsPath) {  
      NSArray *searchPaths =  
       NSSearchPathForDirectoriesInDomains  
       (NSDocumentDirectory, NSUserDomainMask, YES);  
      _documentsPath = [searchPaths objectAtIndex: 0];  
      [_documentsPath retain];  
     }  
     return _documentsPath;  
    }  
       
    //(document目录的路径)  
     NSString *destinationString = [[self documentsPath]  
       stringByAppendingPathComponent:filenameField.text];  
     NSURL *destinationURL = [NSURL fileURLWithPath: destinationString];  
    //初始化AVAudioRecorder  
     NSError *recorderSetupError = nil;  
     AVAudioRecorder audioRecorder = [[AVAudioRecorder alloc] initWithURL:destinationURL  
       settings:recordSettings error:&recorderSetupError];  
     [recordSettings release];  

第二个参数  settings是一个容纳键值对的NSDictionary有四种一般的键
1:一般的音频设置
2:线性PCM设置
3:编码器设置
4:采样率转换设置

NSMutableDictionary  需要加入五个设置值(线性PCM)
v

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    NSMutableDictionary *recordSettings =  
      [[NSMutableDictionary alloc] initWithCapacity:10];  
      //1 ID号  
      [recordSettings setObject:  
       [NSNumber numberWithInt: kAudioFormatLinearPCM] forKey: AVFormatIDKey];  
      float sampleRate =  
       [pcmSettingsViewController.sampleRateField.text floatValue];  
      //2 采样率  
      [recordSettings setObject:  
       [NSNumber numberWithFloat:sampleRate] forKey: AVSampleRateKey];  
         
      //3 通道的数目  
      [recordSettings setObject:  
       [NSNumber numberWithInt:  
        (pcmSettingsViewController.stereoSwitch.on ? 2 : 1)]  
       forKey:AVNumberOfChannelsKey];  
      int bitDepth =  
       [pcmSettingsViewController.sampleDepthField.text intValue];  
         
      //4 采样位数  默认 16  
      [recordSettings setObject:  
       [NSNumber numberWithInt:bitDepth] forKey:AVLinearPCMBitDepthKey];  
         
      //5  
      [recordSettings setObject:  
       [NSNumber numberWithBool:  
         pcmSettingsViewController.bigEndianSwitch.on]  
        forKey:AVLinearPCMIsBigEndianKey];  
       
      //6 采样信号是整数还是浮点数  
      [recordSettings setObject:  
       [NSNumber numberWithBool:  
         pcmSettingsViewController.floatingSamplesSwitch.on]  
        forKey:AVLinearPCMIsFloatKey]  


;

AVAudioRecorder成功创建后,使用他非常直接.它的三个基本方法如下
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  -(void) startRecording {  
     [audioRecorder record];  
    }  
    -(void) pauseRecording {  
     [audioRecorder pause];  
     recordPauseButton.selected = NO;  
    }  
    -(void) stopRecording {  
     [audioRecorder stop];  
    }