ios转场动画总结

1.简单push动画和present动画

[self.navigationController.view.layer addAnimation:[self pushAnimation] forKey:@""];
[self.navigationController pushViewController:[] animated:NO];

[self.view.window.layer addAnimation:[self presentAnimation] forKey:nil];
[self presentViewController:second animated:NO completion:nil]; 

//系统的API
- (void)addAnimation:(CAAnimation *)anim forKey:(nullable NSString *)key;

自定义push动画，然后在push时添加到navigationController中
CATransition -> CAAnimation -> NSObject

    CATransition *transition = [CATransition animation];
    transition.duration = 0.6;
    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];
    
    //动画类型，一下是系统API的介绍
    /* The name of the transition. Current legal transition types include
     * `fade', `moveIn', `push' and `reveal'. Defaults to `fade'. */
    transition.type = @"";

    /*私有API
     cube                   立方体效果
     pageCurl               向上翻一页
     pageUnCurl             向下翻一页
     rippleEffect           水滴波动效果
     suckEffect             变成小布块飞走的感觉
     oglFlip                上下翻转
     cameraIrisHollowClose  相机镜头关闭效果
     cameraIrisHollowOpen   相机镜头打开效果
     */

最后push或present页面就可以完成动画

2.非交互式转场动画

1.需要当前的navigationController遵循<UINavigationControllerDelegate>并实现其代理方法

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

可以在此代理方法中判断当前是push还是pop

2.我们需要在代理方法中返回一个UIViewControllerAnimatedTransitioning对象，于是我们创建一个类继承自NSObject，遵循<UIViewControllerAnimatedTransitioning>协议，并实现其代理方法
代理方法主要有以下2个

// This is used for percent driven interactive transitions, as well as for
// container controllers that have companion animations that might need to
// synchronize with the main animation.
- (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext;

// This method can only  be a nop if the transition is interactive and not a percentDriven interactive transition.
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext;

第一个方法将返回动画的时长
第二个方法将具体实现动画

//转场过渡的容器view
UIView *containerView = [transitionContext containerView];
//FromVC
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIView *fromView = fromViewController.view;

//ToVC
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *toView = toViewController.view;

NSInteger toVCCount = [toViewController.navigationController.viewControllers indexOfObject:toViewController];
NSInteger fromVCCount = [fromViewController.navigationController.viewControllers indexOfObject:fromViewController];
if (toVCCount > fromVCCount) {
   //push
    [containerView addSubview:fromView];
    [containerView addSubview:toView];
}
else{
  //pop
    [containerView addSubview:toView];
    [containerView addSubview:fromView];
}

[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        //具体的动画实现

  } completion:^(BOOL finished) {
        BOOL wasCancelled = [transitionContext transitionWasCancelled];
        //设置transitionContext通知系统动画执行完毕
        [transitionContext completeTransition:!wasCancelled];
}];

实现酷狗的转场动画
分别创建两个类继承自NSObject，遵循<UIViewControllerAnimatedTransitioning>协议，来实现push和pop的动画效果

1.push动画,将将push的view做仿射变换

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext;

//转场过渡的容器view
UIView *containerView = [transitionContext containerView];
//ToVC
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *toView = toViewController.view;
[containerView addSubview:toView];

//将toView绕原点旋转45度
toView.transform = 

2.pop动画同理

3.交互式转场动画

<UINavigationControllerDelegate>实现其代理方法

- (nullable id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController
                          interactionControllerForAnimationController:(id <UIViewControllerAnimatedTransitioning>) animationController

实现这个方法，系统转场时，就会知道当前是否有交互式的转场，有便执行交互转场，无则执行普通自定义的转场动画
UIPercentDrivenInteractiveTransition类是系统定义的，他遵循UIViewControllerInteractiveTransitioning协议
此类提供了了以下方法

// These methods should be called by the gesture recognizer or some other logic
// to drive the interaction. This style of interaction controller should only be
// used with an animator that implements a CA style transition in the animator's
// animateTransition: method. If this type of interaction controller is
// specified, the animateTransition: method must ensure to call the
// UIViewControllerTransitionParameters completeTransition: method. The other
// interactive methods on UIViewControllerContextTransitioning should NOT be
// called. If there is an interruptible animator, these methods will either scrub or continue 
// the transition in the forward or reverse directions.

- (void)updateInteractiveTransition:(CGFloat)percentComplete;
- (void)cancelInteractiveTransition;
- (void)finishInteractiveTransition;

根据pop时传递的手势信息来计算滑动百分比，从而完成交互动画和取消动画