IOS-闪光灯操作

enum {

AVCaptureDevicePositionBack                = 1,

AVCaptureDevicePositionFront               = 2

};

typedef NSInteger AVCaptureDevicePosition;

闪光灯开关

enum {

AVCaptureFlashModeOff  = 0,

AVCaptureFlashModeOn   = 1,

AVCaptureFlashModeAuto = 2

};

typedef NSInteger AVCaptureFlashMode;

手电筒开关

enum {

AVCaptureTorchModeOff  = 0,

AVCaptureTorchModeOn   = 1,

AVCaptureTorchModeAuto = 2,

};

typedef NSInteger AVCaptureTorchMode;

焦距调整

enum {

AVCaptureFocusModeLocked              = 0,

AVCaptureFocusModeAutoFocus           = 1,

AVCaptureFocusModeContinuousAutoFocus = 2,

};

typedef NSInteger AVCaptureFocusMode;

曝光量调节

enum {

AVCaptureExposureModeLocked = 0,

AVCaptureExposureModeAutoExpose = 1,

AVCaptureExposureModeContinuousAutoExposure = 2,

};

typedef NSInteger AVCaptureExposureMode;

白平衡

enum {

AVCaptureWhiteBalanceModeLocked         = 0,

AVCaptureWhiteBalanceModeAutoWhiteBalance         = 1,

    AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance = 2,

};

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];
}

from：http://stackoverflow.com/a/3204078