检测设备摄像头、指南针、录音、陀螺仪状态的iOS代码

//检查前后摄像头  BOOL cameraAvailable = [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];//前  BOOL frontCameraAvailable = [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];//后    //检查指南针 CoreLocation.framework  <CoreLocation/CoreLocation.h>  BOOL magnetometerAvailbale = [CLLocationManager headingAvailable];    //检查声音支持 AVFoundation.framework <AVFoundation/AVFoundation.h>  AVAudioSession *audioSession = [AVAudioSession sharedInstance];  //返回一个AVAudioSession实例  BOOL audioAvailable = audioSession.inputAvailable;//bool值。获取是否支持    //检查录像支持 MobileCoreServices.framework <MobileCoreServices/MobileCoreServices.h>  - (BOOL)isvideoCameraAvailable  {      //简单检查所有的可用的媒体资源类型，然后检查返回的数组，如果其中包含了kUTTypeMovie的NSString类型对象，就证明摄像头支持录像      UIImagePickerController *picker = [[UIImagePickerController alloc]init];      NSArray *sourceTypes = [UIImagePickerController availableMediaTypesForSourceType:picker.sourceType];//返回所支持的media的类型数组      [picker release];        if (![sourceTypes containsObject:(NSString *)kUTTypeMovie]) {//containsObject确定数组中是否包含后面的对象          return NO;      }      return YES;  }        //检查陀螺仪可用 CoreMotion.framework <CoreMotion/CoreMotion.h>  - (BOOL) isGyroscopeAvailable  {  #ifdef __IPHONE_4_0//4.0之后才有      CMMotionManager *motionManager = [[CMMotionManager alloc]init];      BOOL gyroscopeAvailable = motionManager.gyroAvailable;      [motionManager release];      return gyroscopeAvailable;  #else      return NO;  #endif  }