效果图
原理
自动定义 present 和 dismiss 动画,设置 viewController 的 transitioningDelegate 为自定义类对象(ImageOpeningTransitioningDelegate),自己实现过渡动画即可,本文主要讲解present自定义过渡实现
1.设置 transitioningDelegate 为 self.customTransitioningDelegate,该对象遵循 UIViewControllerTransitioningDelegate 协议,
...
VideoDetailsViewController *detailsViewController = [[VideoDetailsViewController alloc] init];
detailsViewController.transitioningDelegate = self.customTransitioningDelegate;
...
[self presentViewController:detailsViewController animated:YES completion:nil];
2.在 present 控制器时,会调用其animationControllerForPresentedController:presentingController: 方法,该方法需要返回一个遵守 UIViewControllerAnimatedTransitioning 协议的对象,这里我们单独抽象出一个类(ImageOpeningPresenter),
-(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
return [ImageOpeningPresenter new];
}
UIViewControllerAnimatedTransitioning 协议需要实现的方法
@protocol UIViewControllerAnimatedTransitioning <NSObject>
// 过渡动画需要的事件
- (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext;
// 过渡上下文, transitionContext 包含参与过渡的对象,比如目标控制器和源控制器,拿到这两个控制器我们就可以写交互动画了
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext;
@optional
3.重写 animateTransition: 方法
通过 transitionContext 获取源控制器和目标控制器
ViewController *sourceViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
VideoDetailsViewController *targetViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
获取 containerView ,这个视图是最底层的 view,相当于整个过渡动画的舞台,所有对象的动画过程都在它上面呈现
UIView *containerView = [transitionContext containerView];
过渡动画代码
/// 完整动画代码在 ImageOpeningPresenter.m 文件 animateTransition: 方法中
NSTimeInterval animationDuration = [self transitionDuration:transitionContext];
...
[UIView animateWithDuration:animationDuration delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{
...
}
completion:^(BOOL finished) {
...
// 转场结束,这个代码很关键,一定要调用
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
