作品链接：
http://www.jianshu.com/users/1e0f5e6f73f6/top_articles
1.导入第三方框架

#import <AVFoundation/AVFoundation.h>

2.声明录音对象

@property (nonatomic, strong) AVAudioRecorder *recorder;

3.#pragma mark - 懒加载代码

- (AVAudioRecorder *)recorder
{
    if (_recorder == nil) {
        // 1.创建沙盒路径
        NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
        
        // 2.拼接音频文件
        NSString *filePath = [path stringByAppendingPathComponent:@"123.mp3"];
        
        // 3.转化成url file://
        NSURL *url = [NSURL fileURLWithPath:filePath];
        
        // 4.设置录音的参数
        NSDictionary *settingRecorder = @{
                                          // 音质
                                          AVEncoderAudioQualityKey : [NSNumber numberWithInteger:AVAudioQualityLow],
                                          // 比特率
                                          AVEncoderBitRateKey : [NSNumber numberWithInteger:16],
                                          // 采样率
                                          AVSampleRateKey : [NSNumber numberWithFloat:8000],
                                          // 声道  视频2.1 录音 2.
                                          AVNumberOfChannelsKey : [NSNumber numberWithInteger:2]
                                          };
        
        
        // 5.创建录音对象
        self.recorder = [[AVAudioRecorder alloc] initWithURL:url settings:settingRecorder error:nil];
        
        NSLog(@"%@,%@",filePath,path);
    }
    return _recorder;
}

3.#pragma mark - 点击事件

// 开始录音
- (IBAction)start {
    [self.recorder record];
}

// 结束录音
- (IBAction)stop {
    [self.recorder stop];
}