AVAuthorizationStatus state = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo]; ／／获取相机的访问权限
四种枚举 值。
AVAuthorizationStatusNotDetermined = 0,
AVAuthorizationStatusRestricted,
AVAuthorizationStatusDenied,
AVAuthorizationStatusAuthorized
ALAuthorizationStatus state = [ALAssetsLibrary authorizationStatus]; 获取相册的访问权限
ALAuthorizationStatusNotDetermined = 0, // User has not yet made a choice with regards to this application
ALAuthorizationStatusRestricted, // This application is not authorized to access photo data.
// The user cannot change this application’s status, possibly due to active restrictions
// such as parental controls being in place.
ALAuthorizationStatusDenied, // User has explicitly denied this application access to photos data.
ALAuthorizationStatusAuthorized // User has authorized this application to access photos data.