在非常多场景中。我们都须要实现各种动画。这回我们来尝试搞一下控制器间跳转的modal动画。

 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    ZYSecondViewController *second = [[ZYSecondViewController alloc]init];

    second.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;


    [self presentViewController:second animated:YES completion:nil];

}

• 上面是系统提供的动画的样式，可是系统提供的动画有时候满足不了我们的需求，所以我们就要自己定义动画了。我们接下来。就重点的来说一下自己定义动画这一块的内容。

• 准备工作：我之前写过的单例：一行代码搞定单例

• 以及一些坐标的扩展，这里我们直接调用一下：

• ZYtransition.h（单例）

#import "Singleton.h"
@interface ZYtransition : NSObject <UIViewControllerTransitioningDelegate>
SingletonH(transition)
@end

• ZYtransition.m

#import "ZYtransition.h"
#import "ZYAnimatedTransitioning.h"
#import "ZYPresentationController.h"
@implementation ZYtransition
SingletonM(transition)

 - (UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented presentingViewController:(UIViewController *)presenting sourceViewController:(UIViewController *)source
{

    ZYPresentationController *pc = [[ZYPresentationController alloc]initWithPresentedViewController:presented presentingViewController:presenting];
    return pc;
}
 - (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
    ZYAnimatedTransitioning *anim = [[ZYAnimatedTransitioning alloc]init];
    anim.presented = YES;
    return anim;
}

 - (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
    ZYAnimatedTransitioning *anim = [[ZYAnimatedTransitioning alloc]init];
    anim.presented = NO;
    return anim;
}

• ZYAnimatedTransitioning.h (负责动画)

@interface ZYAnimatedTransitioning : NSObject<UIViewControllerAnimatedTransitioning>
@property(nonatomic,assign)BOOL presented;
@end

• ZYAnimatedTransitioning.m

const NSTimeInterval duraton  = 0.5;
@implementation ZYAnimatedTransitioning
 - (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext
{
    return  duraton;
}
 - (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
    //   UITransitionContextToViewKey
    //   UITransitionContextFromViewKey

    if (self.presented)
    {
        UIView *toView =  [transitionContext viewForKey:UITransitionContextToViewKey];

        toView.y = -toView.height;

        [UIView animateWithDuration:duraton animations:^{
            toView.y = 0;
        } completion:^(BOOL finished) {
            [transitionContext completeTransition:YES];

        }];
    }else
    {
        UIView *fromView =  [transitionContext viewForKey:UITransitionContextFromViewKey];

        [UIView animateWithDuration:duraton animations:^{
            fromView.y = -fromView.height;
        } completion:^(BOOL finished) {
            [transitionContext completeTransition:YES];

        }];
    }
}
@end

• 搞一个ZYPresentationController
  .h

@interface ZYPresentationController : UIPresentationController

.m

@implementation ZYPresentationController

- (void)presentationTransitionWillBegin
{

    self.presentedView.frame = self.containerView.bounds;
    [self.containerView addSubview:self.presentedView];
}
- (void)presentationTransitionDidEnd:(BOOL)completed
{
//    NSLog(@"%s",__func__);
}
- (void)dismissalTransitionWillBegin
{
//    NSLog(@"%s",__func__);
}
- (void)dismissalTransitionDidEnd:(BOOL)completed
{
    [self.presentedView removeFromSuperview];
}
@end

这种话，我们外面用起来就非常easy了：

#import "ViewController.h"
#import "ZYSecondViewController.h"
#import "ZYtransition.h"
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    ZYSecondViewController *second = [[ZYSecondViewController alloc]init];


    second.modalPresentationStyle = UIModalPresentationCustom;


    second.transitioningDelegate = [ZYtransition sharedtransition];

    [self presentViewController:second animated:YES completion:nil];

}


@end

外面仅仅须要跟平时一样。然后设置显示的样式为自己定义，然后制定代理。就能实现modal的自己定义动画效果了。