在应用程序的某个时刻,会出现一个特定的UIViewController,我们将其称为mainViewController(缩短的mainVC).
mainVC通过代码使用以下代码呈现另一个视图控制器(出于隐私原因,我删除了部分代码)：
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"SecondaryStoryboard" bundle:secondaryBundle]; SecondViewController *secondVC = [storyboard instantiateInitialViewController]; [self presentViewController:secondVC animated:YES completion:nil];
因此,第二个VC将在稍后呈现另一个名为thirdVC的视图控制器.这是使用自定义segue完成的,在上面的代码中使用的故事板中设置,代码如下所示：
@implementation VCCustomPushSegue
- (void)perform {
UIView *sourceView = ((UIViewController *)self.sourceViewController).view;
UIView *destinationView = ((UIViewController *)self.destinationViewController).view;
UIWindow *window = [[[UIApplication sharedApplication] delegate] window];
destinationView.center = CGPointMake(sourceView.center.x + sourceView.frame.size.width,destinationView.center.y);
[window insertSubview:destinationView aboveSubview:sourceView];
[UIView animateWithDuration:0.4
animations:^{
destinationView.center = CGPointMake(sourceView.center.x,destinationView.center.y);
sourceView.center = CGPointMake(0 - sourceView.center.x,destinationView.center.y);
}
completion:^(BOOL finished){
[self.sourceViewController presentViewController:self.destinationViewController animated:NO completion:nil];
}];
}
@end
正如您所看到的,这个segue以模态方式(通过使用presentViewController :)以自定义动画(从右到左的幻灯片)呈现目标视图控制器.
所以基本上到这里一切都很好.我用经典的模态动画(从底部向上滑动)呈现第二个VC,并使用我的自定义过渡呈现第三个VC.
但是当我想要解雇第三个VC时,我想要的是直接回到mainVC.所以我从第三个VC调用以下内容：
self.modalTransitionStyle = UIModalTransitionStyleCoverVertical; [self.presentingViewController.presentingViewController dismissViewControllerAnimated:_animate completion:nil];
这样,我正在调用dismissViewControllerAnimated：直接在mainVC上调用(由self.presentingViewController.presentingViewController引用),我期待第三个VC被动画解散,而第二个VC只是在没有动画的情况下消失.
正如Apple在UIViewController类文档中所说：
The presenting view controller is responsible for dismissing the view
controller it presented. If you call this method on the presented view
controller itself,it automatically forwards the message to the
presenting view controller.If you present several view controllers in succession,thus building a
stack of presented view controllers,calling this method on a view
controller lower in the stack dismisses its immediate child view
controller and all view controllers above that child on the stack.
When this happens,only the top-most view is dismissed in an animated
fashion; any intermediate view controllers are simply removed from the
stack. The top-most view is dismissed using its modal transition
style,which may differ from the styles used by other view controllers
lower in the stack.
问题是它不会发生什么.在我的场景中,第三个VC消失,并显示第二个VC被解雇,经典模态幻灯片到底部动画.
我究竟做错了什么 ？
编辑：
所以@codeFi的答案可能在一个经典项目中工作,但问题在于我正在研究一个框架.所以mainVC将在客户端应用程序中,而第二个VC和第三个VC在我的框架中,在一个单独的故事板中.除了在我的代码中对它的引用之外,我没有任何其他方式访问mainVC,所以很遗憾,unwind segues不是一个选项.
解决方法
if (self.presentedViewController.presentedViewController) {
[self.presentedViewController.view addSubview:[[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO]];
}
[self dismissViewControllerAnimated:YES completion:nil];
不漂亮,但它似乎工作.
注意：如果您的secondVC有一个导航栏,您需要在快照屏幕和将快照作为子视图添加到secondVC之间隐藏导航栏,否则快照将显示在导航栏下方,因此看似显示双导航在解雇动画期间的酒吧.码：
if (self.presentedViewController.presentedViewController) {
UIView *snapshot = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO];
[self.presentedViewController.navigationController setNavigationBarHidden:YES animated:NO];
[self.presentedViewController.view addSubview:snapshot];
}
[self dismissViewControllerAnimated:YES completion:nil];
