iOS 自定义转场动画篇

前言: 自定义转场动画其实并不难, 关键在于能够明白思路, 也就是操作步骤. 本篇博客主要以present转场动画为例, 进行分析, 操作, 如有错误欢迎简信与我交流.

不进行修改的话,

presentViewController:animated:completion:

相信这个方法很多人都是用过, 称作模态推出界面, 默认都是从屏幕下方推出新的控制器.

自定义的目的就是为了修改固定的推出方式, 同时加上你想要的动画.

一个关键的概念:

UIViewControllerAnimatedTransitioning

控制动画的协议, 需要自己实现这个. 下面来一看看代码如何进行实现.

@interface ViewController ()<UIViewControllerTransitioningDelegate>

跳转点击方法

- (void)click:(UIButton *)sender
{
ModelViewController *modalViewController = [ModelViewController new];
// 指定代理
modalViewController.transitioningDelegate = self;
// Style = 自定义方式
modalViewController.modalPresentationStyle = UIModalPresentationCustom;
[self presentViewController:modalViewController
animated:YES
completion:NULL];
}

UIViewControllerTransitioningDelegate

// 修改动画的两个相关的协议方法, 建议仔细查看UIViewControllerTransitioningDelegate里面的注释
-(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented
presentingController:(UIViewController *)presenting
sourceController:(UIViewController *)source
{
// 推出动画 - 下面会给出代码 我参照POP动画Demo写的.
return [PresentAnimator new];
}

- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
// 退出
return [DismissAnimator new];
}
// 想要实现手势控制可在这个方法中进行修改
-(id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator {

}

关键在于动画如何实现 分别进行的实现PresentAnimator, DismissAnimator的实现.

UIViewControllerAnimatedTransitioning

使用这个协议进行修改.

@interface PresentAnimator : NSObject <UIViewControllerAnimatedTransitioning>

PresentAnimator.m

// 交互所用时间
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 0.5f;
}
// 具体动画方式, 上面提到的POP
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
// 这里拿到即将新推出的VC的View
UIView *toView = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;
// 这里设置退出view具体如何设置
toView.frame = CGRectMake(0,0, SCREEN_WIDTH, SCREEN_HEIGHT);
toView.center = CGPointMake(transitionContext.containerView.center.x, -transitionContext.containerView.center.y);

[transitionContext.containerView addSubview:toView];
// pop动画
POPSpringAnimation *positionAnim = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerPositionY];
positionAnim.toValue = @(transitionContext.containerView.center.y);
positionAnim.springBounciness = 10;
[positionAnim setCompletionBlock:^(POPAnimation *anim, BOOL finished) {
[transitionContext completeTransition:YES];
}];
POPSpringAnimation *scaleAnim = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
scaleAnim.springBounciness = 20;
scaleAnim.fromValue = [NSValue valueWithCGPoint:CGPointMake(1.2, 1.4)];

[toView.layer pop_addAnimation:positionAnim forKey:@"positionAnimation"];
[toView.layer pop_addAnimation:scaleAnim forKey:@"scaleAnimation"];
}

DismissAnimator.m

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 0.5f;
}

- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
// fromVC 很好理解吧?? 就是从哪个控制器推过来回到哪里去.
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
POPBasicAnimation *offscreenAnimation = [POPBasicAnimation animationWithPropertyNamed:kPOPLayerPositionY];
offscreenAnimation.toValue = @(-fromVC.view.layer.position.y);
[offscreenAnimation setCompletionBlock:^(POPAnimation *anim, BOOL finished) {
[transitionContext completeTransition:YES];
}];
[fromVC.view.layer pop_addAnimation:offscreenAnimation forKey:@"offscreenAnimation"];
}

顺便值得一提的是UINavigationController转场的动画也是可以自定义的. 通过这个

UINavigationControllerDelegate

来完成

// 签订这个协议
self.navigationController.delegate = self;

- (id<UIViewControllerAnimatedTransitioning>) navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC
{

if (operation == UINavigationControllerOperationPush) {
// 动画的方式不变
return [PresentAnimator new];
}else{
return nil;
}
}