1、硬件設備獲取

iOS10以后使用AVCaptureDeviceDiscoverySession獲取手機的相關硬件設備

/*AVCaptureDeviceType
  AVCaptureDeviceTypeBuiltInMicrophone   麥克風
 AVCaptureDeviceTypeBuiltInWideAngleCamera 內置廣角相機
 AVCaptureDeviceTypeBuiltInTelephotoCamera 內置長焦相機
 */
AVCaptureDeviceDiscoverySession *devicesIOS10 = [AVCaptureDeviceDiscoverySession  discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
        
NSArray *devicesIOS  = devicesIOS10.devices;
 for (AVCaptureDevice *device in devicesIOS) {
      if ([device position] == position) {
         return device;
     }
 }

2、攝像機拍照功能實現

iOS10之后使用AVCapturePhotoOutput實現相機的拍照功能。

AVCaptureDevice *audioCatureDevice = nil;
        /*AVCaptureDeviceType
         AVCaptureDeviceTypeBuiltInMicrophone   麥克風
         AVCaptureDeviceTypeBuiltInWideAngleCamera 內置廣角相機
         AVCaptureDeviceTypeBuiltInTelephotoCamera 內置長焦相機
         */
 //獲取后置攝像頭       
AVCaptureDeviceDiscoverySession *devicesIOS10 = [AVCaptureDeviceDiscoverySession  discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInMicrophone] mediaType:AVMediaTypeAudio position:AVCaptureDevicePositionUnspecified];
NSArray *devicesIOS  = devicesIOS10.devices;
if (devicesIOS.count>0) {
    audioCatureDevice = devicesIOS.firstObject;
}
    error = nil;
//初始化攝像頭輸入對象
    AVCaptureDeviceInput *audioCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioCatureDevice error:&error];
    if (error) {
        HJLog(@"獲取設備輸入對象時出現問題。");
        return;
    }
//將攝像頭輸入對象加入到aptureSession中
if ([self.captureSession canAddInput:self.captureDeviceInput]) {
        [self.captureSession addInput:self.captureDeviceInput];
    }
//初始化圖片輸出對象，并加入到aptureSession中
self.captureSession = [[AVCaptureSession alloc] init];
 self.captureImageOutputIOS10 = [[AVCapturePhotoOutput alloc] init];
 if ([self.captureSession canAddOutput:self.captureImageOutputIOS10]) {
        [self.captureSession addOutput:self.captureImageOutputIOS10];
   }
//初始化圖像預覽層。
    self.captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:self.captureSession];
    self.captureVideoPreviewLayer.frame = self.view.bounds;
    self.captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    [self.view.layer insertSublayer:self.captureVideoPreviewLayer atIndex:0];
    
    [self.captureSession startRunning];

capturePhotoWithSettings: delegate:方法為獲取相機當前截圖，AVCapturePhotoSettings對象在該方法每次調用時都應該從新創(chuàng)建，否則程序會崩潰。設置代理為當前控制器，并且在當前控制器實現代理方法。

 AVCaptureConnection *captureConnection = [self.captureImageOutputIOS10 connectionWithMediaType:AVMediaTypeVideo];
if (!captureConnection) {
      HJLog(@"拍照失?。?);
      return;
}
//每次需重新創(chuàng)建
AVCapturePhotoSettings *setting = [AVCapturePhotoSettings photoSettings];
//閃光燈狀態(tài)在此處設置
if (self.isFlash) {
      setting.flashMode = AVCaptureFlashModeOn;
 }else{
       setting.flashMode = AVCaptureFlashModeOff;
 }
 [self.captureImageOutputIOS10 capturePhotoWithSettings:setting delegate:self];

實現代理方法，獲取相機拍攝圖片（iOS 10到iOS 11）

#pragma mark -  captureOutput delegate
#ifdef __IPHONE_10_0
- (void)captureOutput:(AVCapturePhotoOutput *)captureOutput didFinishProcessingPhotoSampleBuffer:(nullable CMSampleBufferRef)photoSampleBuffer previewPhotoSampleBuffer:(nullable CMSampleBufferRef)previewPhotoSampleBuffer resolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings bracketSettings:(nullable AVCaptureBracketedStillImageSettings *)bracketSettings error:(nullable NSError *)error{
    NSData *imageData = [AVCapturePhotoOutput  JPEGPhotoDataRepresentationForJPEGSampleBuffer:photoSampleBuffer previewPhotoSampleBuffer:previewPhotoSampleBuffer];
    self.photoShowView.image = [UIImage imageWithData:imageData];
    [self.captureSession stopRunning];
    
}
#endif

iOS 11以后獲取拍攝圖片方法

#ifdef __IPHONE_11_0
- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhoto:(AVCapturePhoto *)photo error:(nullable NSError *)error{
    NSData *imageData = [photo  fileDataRepresentation];
    [self.captureSession stopRunning];
}

#endif