- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{   
    // bug fixes: UIIMagePickerController使用中偷换StatusBar颜色的问题
    if ([navigationController isKindOfClass:[UIImagePickerController class]] &&
        ((UIImagePickerController *)navigationController).sourceType ==     UIImagePickerControllerSourceTypePhotoLibrary) {
        [[UIApplication sharedApplication] setStatusBarHidden:NO];
        [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:NO];
    }
}