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                = 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：

 1 AVCaptureDevice* d = nil; // find a device by position
 2 NSArray* allDevices = [AVCaptureDevice devices];
 3 for (AVCaptureDevice* currentDevice in allDevices) {
 4     if (currentDevice.position == AVCaptureDevicePositionBack) {
 5             d = currentDevice;
 6     }
 7 } // at this point, d may still be nil, assuming we found something we like....
 8 NSError* err = nil;
 9 BOOL lockAcquired = [d lockForConfiguration:&err];
10 if (!lockAcquired) {
11     // log err and handle...
12 } else {
13     // flip on the flash mode
14     if ([d hasFlash] && [d isFlashModeSupported:AVCaptureFlashModeOn] ) {
15     [d setFlashMode:AVCaptureFlashModeOn];
16     }
17     [d unlockForConfiguration];
18 }