如何在自定义过渡中更新StatusBar样式

我正在使用iOS 7UIviewControllerAnimatedTransitioning协议来呈现ViewController带有自定义动画的模态。动画正常工作，但是，我希望新呈现的ViewController状态栏样式与呈现的VC不同。

我看到的是-(UIStatusBarStyle)preferredStatusBarStyle在PRESENTING ViewController（实际上是几次）上被调用，而从未在新呈现的上被调用ViewController。如果删除自定义动画，则状态栏上的所有内容均会按预期工作。

我需要在animateTransition函数中做一些特别的事情来更新根视图控制器吗？我尝试过手动设置statusBar，[UIApplication sharedApplication] setStatusBarStyle但是它不起作用（我认为是因为我使用的是基于ios 7视图控制器的状态栏样式）。

这是我的animateTransition代码：

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UICollectionViewCell *activeCell;
    if ([self.collectionView.visibleCells containsObject:self.cellForActiveIdeaVC]) {
        activeCell = self.cellForActiveIdeaVC;
    }

    UIView *container = transitionContext.containerView;
    UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIView *fromView = fromVC.view;
    UIView *toView = toVC.view;

    CGRect beginFrame;
    if (activeCell) {
        beginFrame = [container convertRect:activeCell.bounds fromView:activeCell];
    } else {
        beginFrame = CGRectMake(container.width / 2, container.height / 2, 0, 0);
    }

    CGRect endFrame = [transitionContext initialFrameForViewController:fromVC];

    UIView *move = nil;
    if (toVC.isBeingPresented) {
        toView.frame = endFrame;
        move = [toView snapshotViewAfterScreenUpdates:YES];
        move.frame = beginFrame;
    } else {
        if (activeCell) {
            move = [activeCell snapshotViewAfterScreenUpdates:YES];
        } else {
            move = [fromView snapshotViewAfterScreenUpdates:YES];
        }
        move.frame = fromView.frame;
        [fromView removeFromSuperview];
    }
    [container addSubview:move];

    [UIView animateWithDuration:.5
                          delay:0
         usingSpringWithDamping:700
          initialSpringVelocity:15
                        options:0
                     animations:^{
                         move.frame = toVC.isBeingPresented ?  endFrame : beginFrame;
                     }
                     completion:^(BOOL finished) {
                         [move removeFromSuperview];

                         if (toVC.isBeingPresented) {
                             toView.frame = endFrame;
                             [container addSubview:toView];
                         } else {
                             if (self.cellForActiveIdeaVC) {
                                 self.cellForActiveIdeaVC = nil;
                             }
                         }

                         [transitionContext completeTransition:YES];
                     }];
}

任何指针，不胜感激！