iOS檢測攝像頭、指南針、陀螺儀的狀態的代碼

//檢查前后攝像頭


(void)cameraBtnAction:(id)sender
{
  BOOL cameraAvailable = [UIImagePickerController isCameraDeviceAvailable:
                                      UIImagePickerControllerCameraDeviceRear];//前

  BOOL frontCameraAvailable = [UIImagePickerController isCameraDeviceAvailable:
                                              UIImagePickerControllerCameraDeviceFront];//后

}

//檢查指南針 CoreLocation.framework  <CoreLocation/CoreLocation.h>

(void)magnetometerBtnAction:(id)sender
{
  BOOL magnetometerAvailbale = [CLLocationManager headingAvailable];
}

//檢查聲音支持 AVFoundation.framework <AVFoundation/AVFoundation.h>

(bool)audioBtnAction:(id)sender
{
  //返回一個AVAudioSession實例

  AVAudioSession *audioSession = [AVAudioSession sharedInstance];
  BOOL audioAvailable = audioSession.inputAvailable;//bool值。獲取是否支持
}

//檢查錄像支持 MobileCoreServices.framework <MobileCoreServices/MobileCoreServices.h>

(BOOL)isvideoCameraAvailable
{
  //簡單檢查所有的可用的媒體資源類型，然后檢查返回的數組，
  //如果其中包含了kUTTypeMovie的NSString類型對象，就證明攝像頭支持錄像
  UIImagePickerController picker = [[UIImagePickerController alloc]init];
  //返回所支持的media的類型數組
  NSArray sourceTypes = [UIImagePickerController availableMediaTypesForSourceType:picker.sourceType];
  [picker release];
  if (![sourceTypes containsObject:(NSString *)kUTTypeMovie]) {//containsObject確定數組中是否包含后面的對象
  return NO;

  }
  return YES;
}

//檢查陀螺儀可用 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
}</pre>