推动视图控制器时"从左到右"的无缝动画？

Question

我有一个带有根视图控制器的应用程序和两个额外的视图控制器.出于设计原因,这些应该看起来是根VC的左侧或右侧.这种空间关系应该以它们出现在屏幕上时呈现给用户的方式来表示.也就是说,通过推动动画.

当按下一个新的视图控制器时,它从右边进入屏幕,这样就可以正常工作或者我的两个VC之一.另一方面,我基于这个例子创建了一个自定义segue,它将使VC从左到右显示.

这可行,但动画本身并不是无缝的.看起来好像视图从左侧推到根VC上 - 看起来好像在视图出现之前有一个黑色背景可见.

我想知道是否有人会知道如何获得一个完全镜像版本的默认"推"(即从右到左)动画？

Answer 1

看看这篇文章.除了过渡本身之外,它只是你想要的.简而言之:

1)创建一个对象来执行动画

@interface Animator : NSObject <UIViewControllerAnimatedTransitioning>
@end

2)成为导航控制器的委托,并在此导航控制器委托方法上回答该动画师的实例:

// in your vc.m
@interface ViewController () <UINavigationControllerDelegate>  // add this

// in view did load
self.navigationController.delegate = self;

// implement this to pass your animator as the thing to be in charge of the transition animation
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController*)fromVC toViewController:(UIViewController*)toVC {

    if (operation == UINavigationControllerOperationPush) {
        return [[Animator alloc] init];
    }
    return nil;
}

3)在你的动画师中,回答持续时间:

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 0.25;
}

4)所有这些都来自文章.剩下要做的唯一事情是实现从左到右的幻灯片.(我更改了文章的代码,从左到右滑动):

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

    CGRect fromVCFrame = fromViewController.view.frame;

    CGFloat width = toViewController.view.frame.size.width;
    [[transitionContext containerView] addSubview:toViewController.view];
    toViewController.view.frame = CGRectOffset(fromVCFrame, -width, 0);

    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        fromViewController.view.frame = CGRectOffset(fromVCFrame, width, 0);
        toViewController.view.frame = fromVCFrame;
    } completion:^(BOOL finished) {
        fromViewController.view.frame = fromVCFrame;
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

我在一个小项目中尝试了所有这些,它的工作非常顺利.