IOS-闪光灯操作

AVCaptureDevice.h主要用来获取iphone一些关于相机设备的属性。
前置和后置摄像头
enum {
AVCaptureDevicePositionBack                = ,
AVCaptureDevicePositionFront               =
};
typedef NSInteger AVCaptureDevicePosition;

闪光灯开关

enum {
AVCaptureFlashModeOff  = ,
AVCaptureFlashModeOn   = ,
AVCaptureFlashModeAuto =
};
typedef NSInteger AVCaptureFlashMode;

手电筒开关

enum {
AVCaptureTorchModeOff  = ,
AVCaptureTorchModeOn   = ,
AVCaptureTorchModeAuto = ,
};
typedef NSInteger AVCaptureTorchMode;

焦距调整

enum {
AVCaptureFocusModeLocked              = ,
AVCaptureFocusModeAutoFocus           = ,
AVCaptureFocusModeContinuousAutoFocus = ,
};
typedef NSInteger AVCaptureFocusMode;

曝光量调节

enum {
AVCaptureExposureModeLocked = ,
AVCaptureExposureModeAutoExpose = ,
AVCaptureExposureModeContinuousAutoExposure = ,
};
typedef NSInteger AVCaptureExposureMode;

白平衡

enum {
AVCaptureWhiteBalanceModeLocked         = ,
AVCaptureWhiteBalanceModeAutoWhiteBalance         = ,
    AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance = ,
};
typedef NSInteger AVCaptureWhiteBalanceMode;

开启闪光灯：

 AVCaptureDevice* d = nil; // find a device by position
 NSArray* allDevices = [AVCaptureDevice devices];
 for (AVCaptureDevice* currentDevice in allDevices) {
     if (currentDevice.position == AVCaptureDevicePositionBack) {
             d = currentDevice;
     }
 } // at this point, d may still be nil, assuming we found something we like....
 NSError* err = nil;
 BOOL lockAcquired = [d lockForConfiguration:&err];
 if (!lockAcquired) {
     // log err and handle...
 } else {
     // flip on the flash mode
     if ([d hasFlash] && [d isFlashModeSupported:AVCaptureFlashModeOn] ) {
     [d setFlashMode:AVCaptureFlashModeOn];
     }
     [d unlockForConfiguration];
 }