//检查前后摄像头 
- (void)cameraBtnAction:(id)sender 
{ 
    BOOL cameraAvailable = [UIImagePickerController isCameraDeviceAvailable: 
                                            UIImagePickerControllerCameraDeviceRear];//前 
    BOOL frontCameraAvailable = [UIImagePickerController isCameraDeviceAvailable: 
                                                    UIImagePickerControllerCameraDeviceFront];//后 
} 
  
//检查指南针 CoreLocation.framework  <CoreLocation/CoreLocation.h> 
- (void)magnetometerBtnAction:(id)sender 
{ 
    BOOL magnetometerAvailbale = [CLLocationManager headingAvailable]; 
} 
  
//检查声音支持 AVFoundation.framework <AVFoundation/AVFoundation.h> 
- (bool)audioBtnAction:(id)sender 
{ 
    //返回一个AVAudioSession实例    
    AVAudioSession *audioSession = [AVAudioSession sharedInstance]; 
    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]; 
    //返回所支持的media的类型数组 
    NSArray *sourceTypes = [UIImagePickerController availableMediaTypesForSourceType:picker.sourceType]; 
    [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 
}