AVFoundation拍摄照片（iOS10新框架）

@interface ViewController () <AVCapturePhotoCaptureDelegate>

@property (nonatomic, strong) AVCaptureSession *captureSession; // 会话
@property (nonatomic, strong) AVCaptureDevice *captureDevice;   // 输入设备
@property (nonatomic, strong) AVCaptureDeviceInput *captureDeviceInput; // 输入源
@property (nonatomic, strong) AVCapturePhotoOutput *photoOutput;    // 图像输出
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer; // 预览画面
@property (nonatomic, strong) AVCapturePhotoSettings *photoSettings;    // 图像设置
@property (nonatomic, assign) AVCaptureFlashMode mode;
@property (nonatomic, assign) AVCaptureDevicePosition position;

@end

- (void)setupCaptureSession {

    self.position = AVCaptureDevicePositionBack;
    // 1. 创建会话
    self.captureSession = [[AVCaptureSession alloc] init];
    self.captureSession.sessionPreset = AVCaptureSessionPresetPhoto;    // 画质

    // 2. 创建输入设备
    self.captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    // 3. 创建输入源
    self.captureDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:self.captureDevice error:nil];

    // 4. 创建图像输出
    self.photoOutput = [[AVCapturePhotoOutput alloc] init];  //iOS10

    // 5. 连接输入与会话
    if ([self.captureSession canAddInput:self.captureDeviceInput]) {
        [self.captureSession addInput:self.captureDeviceInput];
    }

    // 6. 连接输出与会话
    if ([self.captureSession canAddOutput:self.photoOutput]) {
        [self.captureSession addOutput:self.photoOutput];
    }

    // 7. 预览画面
    self.previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.captureSession];
    self.previewLayer.frame = self.view.bounds;
    [self.view.layer insertSublayer:self.previewLayer atIndex:0];

    [self.captureSession startRunning];

}

// 拍摄
- (IBAction)startButtonAction:(UIButton *)sender {

    self.photoSettings = [AVCapturePhotoSettings photoSettingsWithFormat:@{AVVideoCodecKey:AVVideoCodecJPEG}];
    [self.photoSettings setFlashMode:self.mode];
    [self.photoOutput capturePhotoWithSettings:self.photoSettings delegate:self];

}

// 闪光灯开关
- (IBAction)lightAction:(UIButton *)sender {

    if (self.mode == AVCaptureFlashModeOn) {
        [self setMode:AVCaptureFlashModeOff];
    } else {
        [self setMode:AVCaptureFlashModeOn];
    }
}

// 切换前后摄像头
- (IBAction)cameraPosition:(UIButton *)sender {
    if (self.position == AVCaptureDevicePositionBack) {
        self.position = AVCaptureDevicePositionFront;
    } else {
        self.position = AVCaptureDevicePositionBack;
    }
    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithDeviceType:AVCaptureDeviceTypeBuiltInWideAngleCamera mediaType:AVMediaTypeVideo position:self.position];
    if (device) {
        self.captureDevice = device;
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:self.captureDevice error:nil];
        [self.captureSession beginConfiguration];
        [self.captureSession removeInput:self.captureDeviceInput];
        if ([self.captureSession canAddInput:input]) {
            [self.captureSession addInput:input];
            self.captureDeviceInput = input;
            [self.captureSession commitConfiguration];
        }
    }
}

#pragma mark - AVCapturePhotoCaptureDelegate
- (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];
    UIImage *image = [UIImage imageWithData:imageData];
    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
    NSLog(@"%s", __FUNCTION__);
}