检查硬件是否安装有摄像头

 // 判断设备是否有摄像头- (BOOL) isCameraAvailable{    return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];}// 前面的摄像头是否可用- (BOOL) isFrontCameraAvailable{    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];}// 后面的摄像头是否可用- (BOOL) isRearCameraAvailable{    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];}<pre name="code" class="objc">// 判断是否支持某种多媒体类型：拍照，视频- (BOOL) cameraSupportsMedia:(NSString *)paramMediaType sourceType:(UIImagePickerControllerSourceType)paramSourceType{    __block BOOL result = NO;    if ([paramMediaType length] == 0){        NSLog(@"Media type is empty.");        return NO;    }    NSArray *availableMediaTypes =[UIImagePickerControlleravailableMediaTypesForSourceType:paramSourceType];    [availableMediaTypes enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL*stop) {                                                        NSString *mediaType = (NSString *)obj;                                                        if ([mediaTypeisEqualToString:paramMediaType]){                                                            result = YES;                                                            *stop= YES;                                                        }            }];    return result;}// 检查摄像头是否支持录像- (BOOL) doesCameraSupportShootingVideos{    return [self cameraSupportsMedia:( NSString *)kUTTypeMoviesourceType:UIImagePickerControllerSourceTypeCamera];}// 检查摄像头是否支持拍照- (BOOL) doesCameraSupportTakingPhotos{    return [self cameraSupportsMedia:( NSString *)kUTTypeImagesourceType:UIImagePickerControllerSourceTypeCamera];}#pragma mark - 相册文件选取相关// 相册是否可用- (BOOL) isPhotoLibraryAvailable{    return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary];}// 是否可以在相册中选择视频- (BOOL) canUserPickVideosFromPhotoLibrary{    return [self cameraSupportsMedia:( NSString *)kUTTypeMoviesourceType:UIImagePickerControllerSourceTypePhotoLibrary];}// 是否可以在相册中选择视频- (BOOL) canUserPickPhotosFromPhotoLibrary{    return [self cameraSupportsMedia:( NSString *)kUTTypeImagesourceType:UIImagePickerControllerSourceTypePhotoLibrary];}