实例编程iPhone 录音和播放是本文要介绍的内容，最近准备做一个关于录音和播放的项目！查了一些资料，很简单的做了一个，下面我就分享一下iPhone的录音和播放的使用心得。iPhone的录音和播放使用到了media层的内容，media层处于cocoa层之下，用到的很大一部分都是c语言的结构。

1、引入框架。

#import <AVFoundation/AVFoundation.h>

2、创建录音项。

-(void)prepareToRecord 
{ 
AVAudioSession*audioSession=[AVAudioSessionsharedInstance]; 
NSError*err=nil; 
[audioSessionsetCategory:AVAudioSessionCategoryPlayAndRecorderror:&err]; 
if(err){ 
NSLog(@"audioSession:%@%d%@",[errdomain],[errcode],[[erruserInfo]description]); 
return; 
} 
[audioSessionsetActive:YESerror:&err]; 
err=nil; 
if(err){ 
NSLog(@"audioSession:%@%d%@",[errdomain],[errcode],[[erruserInfo]description]); 
return; 
} 
recordSetting=[[NSMutableDictionaryalloc]init]; 
[recordSettingsetValue:[NSNumbernumberWithInt:kAudioFormatLinearPCM]forKey:AVFormatIDKey]; 
[recordSettingsetValue:[NSNumbernumberWithFloat:44100.0]forKey:AVSampleRateKey]; 
[recordSettingsetValue:[NSNumbernumberWithInt:2]forKey:AVNumberOfChannelsKey]; 
[recordSettingsetValue:[NSNumbernumberWithInt:16]forKey:AVLinearPCMBitDepthKey]; 
[recordSettingsetValue:[NSNumbernumberWithBool:NO]forKey:AVLinearPCMIsBigEndianKey]; 
[recordSettingsetValue:[NSNumbernumberWithBool:NO]forKey:AVLinearPCMIsFloatKey]; 
//Createanewdatedfile 
NSDate*now=[NSDatedateWithTimeIntervalSinceNow:0]; 
NSString*caldate=[nowdescription]; 
recorderFilePath=[[NSStringstringWithFormat:@"%@/%@.caf",DOCUMENTS_FOLDER,caldate]retain]; 
NSURL*url=[NSURLfileURLWithPath:recorderFilePath]; 
err=nil; 
recorder=[[AVAudioRecorderalloc]initWithURL:urlsettings:recordSettingerror:&err]; 
if(!recorder){ 
NSLog(@"recorder:%@%d%@",[errdomain],[errcode],[[erruserInfo]description]); 
UIAlertView*alert= 
[[UIAlertViewalloc]initWithTitle:@"Warning" 
message:[errlocalizedDescription] 
delegate:nil 
cancelButtonTitle:@"OK" 
otherButtonTitles:nil]; 
[alertshow]; 
[alertrelease]; 
return; 
} 
//preparetorecord 
[recordersetDelegate:self]; 
[recorderprepareToRecord]; 
recorder.meteringEnabled=YES; 
BOOLaudioHWAvailable=audioSession.inputIsAvailable; 
if(!audioHWAvailable){ 
UIAlertView*cantRecordAlert= 
[[UIAlertViewalloc]initWithTitle:@"Warning" 
message:@"Audioinputhardwarenotavailable" 
delegate:nil 
cancelButtonTitle:@"OK" 
otherButtonTitles:nil]; 
[cantRecordAlertshow]; 
[cantRecordAlertrelease]; 
return; 
} 
}

以上这个方法就是创建了录音项，其中包括录音的路径和一些音频属性，但只是准备录音还没有录，如果要录的话还要加入以下的方法：

(void)startrecorder 
{ 
[recorderrecord]; 
}

这样就在我们创建的路径下开始了录音。完成录音很简单：

(void)stopRecording{ 
[recorderstop]; 
}

这里顺便提一下录音的代理方法：

-(void)audioRecorderDidFinishRecording:(AVAudioRecorder*)aRecordersuccessfully:(BOOL)flag 
{ 
NSLog(@"recordersuccessfully"); 
UIAlertView*recorderSuccessful=[[UIAlertViewalloc]initWithTitle:@""message:@"录音成功"
delegate:selfcancelButtonTitle:@"OK"otherButtonTitles:nil]; 
[recorderSuccessfulshow]; 
[recorderSuccessfulrelease]; 
} 
-(void)audioRecorderEncodeErrorDidOccur:(AVAudioRecorder*)arecordererror:(NSError*)error 
{ 
btnRecorder.enabled=NO; 
UIAlertView*recorderFailed=[[UIAlertViewalloc]initWithTitle:@""message:@"发生错误"
delegate:selfcancelButtonTitle:@"OK"otherButtonTitles:nil]; 
[recorderFailedshow]; 
[recorderFailedrelease]; 
}

以上两个代理方法分别指定了录音的成功或失败。

录音中有一个的录音对象有一个averagePowerForChannel和peakPowerForChannel的属性分别为声音的最高振幅和平均振幅，有了他们就可以做一个动态的振幅的录音效果。

-(void)updateAudioDisplay{ 
if(isStart==NO){ 
currentTimeLabel.text=@"--:--"; 
}else{ 
doublecurrentTime=recorder.currentTime; 
currentTimeLabel.text=[NSStringstringWithFormat:@"d:d", 
(int)currentTime/60, 
(int)currentTime%60]; 
//START:code.RecordViewController.setlevelmeters 
[recorderupdateMeters]; 
[leftLevelMetersetPower:[recorderaveragePowerForChannel:0] 
peak:[recorderpeakPowerForChannel:0]]; 
if(!rightLevelMeter.hidden){ 
[rightLevelMetersetPower:[recorderaveragePowerForChannel:1] 
peak:[recorderpeakPowerForChannel:1]]; 
} 
//END:code.RecordViewController.setlevelmeters 
} 
} 
以上就是录音相关的内容。 
下面说一下播放的方法： 
voidSystemSoundsDemoCompletionProc( 
SystemSoundIDsoundID, 
void*clientData) 
{ 
AudioServicesDisposeSystemSoundID(soundID); 
((AudioRecorderPlayerAppDelegate*)clientData).statusLabel.text=@"Stopped"; 
} 
-(void)playAudio 
{ 
//START:code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound 
//createasystemsoundidfortheselectedrow 
SystemSoundIDsoundID; 
OSStatuserr=kAudioServicesNoError; 
//specialcase:vibrate//震动 
//soundID=kSystemSoundID_Vibrate;//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.vibratesystemsound"/>
//findcorrespondingCAFfile 
//NSString*cafName=[NSStringstringWithFormat:@"%@",recorderFilePath];//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.rowtonumberstring"/>
NSURL*url=[NSURLfileURLWithPath:recorderFilePath]; 
//NSString*cafPath= 
//[[NSBundlemainBundle]pathForResource:cafNameofType:@"caf"];//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.findcafinbundle"/>
//NSURL*cafURL=[NSURLfileURLWithPath:url];//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.
createsystemsound.fileurlwithpath"/>
err=AudioServicesCreateSystemSoundID((CFURLRef)url,&soundID);//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.createsystemsound"/>
//END:code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound 
//START:code.SystemSoundsDemo.SystemSoundsDemoViewController.registercompletionprocandplaysound 
if(err==kAudioServicesNoError){ 
//setupcallbackforsoundcompletion 
err=AudioServicesAddSystemSoundCompletion//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.
createsystemsound.addcompletionproc"/>
(soundID,//soundtomonitor 
NULL,//runloop(NULL==main) 
NULL,//runloopmode(NULL==default) 
SystemSoundsDemoCompletionProc,//callbackfunction//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.completionprocroutine"/>
self//datatoprovideoncallback 
);//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.addcompletionprocend"/>
statusLabel.text=@"Playing";//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.setlabel"/>
AudioServicesPlaySystemSound(soundID);//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.playsound"/>
} 
if(err!=kAudioServicesNoError){//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.errorblockstart"/>
CFErrorReferror=CFErrorCreate(NULL,kCFErrorDomainOSStatus,err,NULL);//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.createcferror"/>
NSString*errorDesc=(NSString*)CFErrorCopyDescription(error);//<labelid="code.SystemSoundsDemo.
SystemSoundsDemoViewController.createsystemsound.copycferrordescription"/>
UIAlertView*cantPlayAlert= 
[[UIAlertViewalloc]initWithTitle:@"CannotPlay:" 
message:errorDesc 
delegate:nil 
cancelButtonTitle:@"OK" 
otherButtonTitles:nil]; 
[cantPlayAlertshow]; 
[cantPlayAlertrelease]; 
[errorDescrelease];//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.releaseerrordescription"/>
CFRelease(error);//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.releaseerror"/>
}//<labelid="code.SystemSoundsDemo.SystemSoundsDemoViewController.createsystemsound.errorblockend"/>
//END:code.SystemSoundsDemo.SystemSoundsDemoViewController.registercompletionprocandplaysound 
}

通过以上的方法就应该能够实现播放，播放的时候也是可以加入振幅过程的，大家可以试试！这样一个iPhone录音机就做好了！哈哈

小结：实例编程iPhone 录音和播放的内容介绍完了，希望本文对你有所帮助。