更新,更简单的自定义转场集成！
写在前面
这两天闲下来好好的研究了一下自定义转场，关于这方面的文章网络上已经很多了，作为新手，我想通过这篇文章把自己这几天的相关学习心得记录一下，方便加深印响和以后的回顾，这是我第一写技术文章，不好之处请谅解，通过这几天的学习，我尝试实现了四个效果，废话不多说，先上效果图：
DEMO ONE：一个弹性的present动画，支持手势present和dismiss
弹性pop
DEMO TWO：一个类似于KeyNote的神奇移动效果push动画，支持手势pop
神奇移动
DEMO THREE：一个翻页push效果，支持手势PUSH和POP
翻页效果
DEMO FOUR：一个小圆点扩散present效果，支持手势dimiss
扩散效果
动手前
大家都知道从iOS7开始，苹果就提供了自定义转场的API，模态推送present和dismiss、导航控制器push和pop、标签控制器的控制器切换都可以自定义转场了，关于过多的理论我就不太多说明了，大家可以先参照onevcat大神的这篇博客：WWDC 2013 Session笔记 - iOS7中的ViewController切换，我想把整个自定义转场的步骤做个总结：
-
我们需要自定义一个遵循的
<UIViewControllerAnimatedTransitioning>协议的动画过渡管理对象，并实现两个必须实现的方法：//返回动画事件 - (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext; //所有的过渡动画事务都在这个方法里面完成 - (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext; 我们还需要自定义一个继承于
UIPercentDrivenInteractiveTransition的手势过渡管理对象，我把它成为百分比手势过渡管理对象，因为动画的过程是通过百分比控制的-
成为相应的代理，实现相应的代理方法，返回我们前两步自定义的对象就OK了 ！
模态推送需要实现如下4个代理方法，iOS8新的那个方法我暂时还没有发现它的用处，所以暂不讨论
//返回一个管理prenent动画过渡的对象 - (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source; //返回一个管理pop动画过渡的对象 - (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed; //返回一个管理prenent手势过渡的对象 - (nullable id <UIViewControllerInteractiveTransitioning>)interactionControllerForPresentation:(id <UIViewControllerAnimatedTransitioning>)animator; //返回一个管理pop动画过渡的对象 - (nullable id <UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id <UIViewControllerAnimatedTransitioning>)animator;导航控制器实现如下2个代理方法
//返回转场动画过渡管理对象 - (nullable id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController interactionControllerForAnimationController:(id <UIViewControllerAnimatedTransitioning>) animationController NS_AVAILABLE_IOS(7_0); //返回手势过渡管理对象 - (nullable id <UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC NS_AVAILABLE_IOS(7_0);标签控制器也有相应的两个方法
//返回转场动画过渡管理对象 - (nullable id <UIViewControllerInteractiveTransitioning>)tabBarController:(UITabBarController *)tabBarController interactionControllerForAnimationController: (id <UIViewControllerAnimatedTransitioning>)animationController NS_AVAILABLE_IOS(7_0); //返回手势过渡管理对象 - (nullable id <UIViewControllerAnimatedTransitioning>)tabBarController:(UITabBarController *)tabBarController animationControllerForTransitionFromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC NS_AVAILABLE_IOS(7_0); 如果看着这些常常的代理方法名头疼的话，没关系，先在demo中用起来吧，慢慢就习惯了，其实哪种自定义转场都只需要这3个步骤，如果不需要手势控制，步骤2还可以取消，现在就让我们动手来实现效果吧
动手吧！
demo one
1、我们首先创建2个控制器，为了方便我称做present操作的为vc1、被present的为vc2，点击一个控制器上的按钮可以push出另一个控制器
2、 然后我们创建一个过渡动画管理的类,遵循<UIViewControllerAnimatedTransitioning>协议，我这里是XWPresentOneTransition,由于我们要同时管理present和dismiss2个动画，你可以实现相应的两个类分别管理两个动画，但是我觉得用一个类来管理就好了，看着比较舒服，逻辑也比较紧密，因为present和dismiss的动画逻辑很类似，写在一起，可以相互参考，所以我定义了一个枚举和两个初始化方法：
XWPresentOneTransition.h
typedef NS_ENUM(NSUInteger, XWPresentOneTransitionType) {
XWPresentOneTransitionTypePresent = 0,//管理present动画
XWPresentOneTransitionTypeDismiss//管理dismiss动画
};
@interface XWPresentOneTransition : NSObject<UIViewControllerAnimatedTransitioning>
//根据定义的枚举初始化的两个方法
+ (instancetype)transitionWithTransitionType:(XWPresentOneTransitionType)type;
- (instancetype)initWithTransitionType:(XWPresentOneTransitionType)type;
3、 然后再.m文件里面实现必须实现的两个代理方法
@implementation XWPresentOneTransition
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
return 0.5;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
//为了将两种动画的逻辑分开，变得更加清晰，我们分开书写逻辑，
switch (_type) {
case XWPresentOneTransitionTypePresent:
[self presentAnimation:transitionContext];
break;
case XWPresentOneTransitionTypeDismiss:
[self dismissAnimation:transitionContext];
break;
}
}
//实现present动画逻辑代码
- (void)presentAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
}
//实现dismiss动画逻辑代码
- (void)dismissAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
}
4、 设置vc2的transitioningDelegate，我就设为它自己咯，我实在vc2的init方法中设置的，并实现代理方法
- (instancetype)init
{
self = [super init];
if (self) {
self.transitioningDelegate = self;
//为什么要设置为Custom，在最后说明.
self.modalPresentationStyle = UIModalPresentationCustom;
}
return self;
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{
//这里我们初始化presentType
return [XWPresentOneTransition transitionWithTransitionType:XWPresentOneTransitionTypePresent];
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed{
//这里我们初始化dismissType
return [XWPresentOneTransition transitionWithTransitionType:XWPresentOneTransitionTypeDismiss];
}
5、 至此我们所有的准备工作就做好了,下面只需要专心在presentAnimation:方法和dismissAnimation方法中实现动画逻辑就OK了，先看presentAnimation:
- (void)presentAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{`
//通过viewControllerForKey取出转场前后的两个控制器，这里toVC就是vc1、fromVC就是vc2
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
//snapshotViewAfterScreenUpdates可以对某个视图截图，我们采用对这个截图做动画代替直接对vc1做动画，因为在手势过渡中直接使用vc1动画会和手势有冲突， 如果不需要实现手势的话，就可以不是用截图视图了，大家可以自行尝试一下
UIView *tempView = [fromVC.view snapshotViewAfterScreenUpdates:NO];
tempView.frame = fromVC.view.frame;
//因为对截图做动画，vc1就可以隐藏了
fromVC.view.hidden = YES;
//这里有个重要的概念containerView，如果要对视图做转场动画，视图就必须要加入containerView中才能进行，可以理解containerView管理着所有做转场动画的视图
UIView *containerView = [transitionContext containerView];
//将截图视图和vc2的view都加入ContainerView中
[containerView addSubview:tempView];
[containerView addSubview:toVC.view];
//设置vc2的frame，因为这里vc2present出来不是全屏，且初始的时候在底部，如果不设置frame的话默认就是整个屏幕咯，这里containerView的frame就是整个屏幕
toVC.view.frame = CGRectMake(0, containerView.height, containerView.width, 400);
//开始动画吧，使用产生弹簧效果的动画API
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 usingSpringWithDamping:0.55 initialSpringVelocity:1.0 / 0.55 options:0 animations:^{
//首先我们让vc2向上移动
toVC.view.transform = CGAffineTransformMakeTranslation(0, -400);
//然后让截图视图缩小一点即可
tempView.transform = CGAffineTransformMakeScale(0.85, 0.85);
} completion:^(BOOL finished) {
//使用如下代码标记整个转场过程是否正常完成[transitionContext transitionWasCancelled]代表手势是否取消了，如果取消了就传NO表示转场失败，反之亦然，如果不用手势present的话直接传YES也是可以的，但是无论如何我们都必须标记转场的状态，系统才知道处理转场后的操作，否者认为你一直还在转场中，会出现无法交互的情况，切记！
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
//转场失败后的处理
if ([transitionContext transitionWasCancelled]) {
//失败后，我们要把vc1显示出来
fromVC.view.hidden = NO;
//然后移除截图视图，因为下次触发present会重新截图
[tempView removeFromSuperview];
}
}];
}
再看dismissAnimation 方法
- (void)dismissAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
//注意在dismiss的时候fromVC就是vc2了，toVC才是VC1了，注意这个关系
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
//参照present动画的逻辑，present成功后，containerView的最后一个子视图就是截图视图，我们将其取出准备动画
UIView *tempView = [transitionContext containerView].subviews[0];
//动画吧
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
//因为present的时候都是使用的transform，这里的动画只需要将transform恢复就可以了
fromVC.view.transform = CGAffineTransformIdentity;
tempView.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) {
if ([transitionContext transitionWasCancelled]) {
//失败了标记失败
[transitionContext completeTransition:NO];
}else{
//如果成功了，我们需要标记成功，同时让vc1显示出来，然后移除截图视图，
[transitionContext completeTransition:YES];
toVC.view.hidden = NO;
[tempView removeFromSuperview];
}
}];
}
6、如果不需要手势控制，这个转场就算完成了，下面我们来添加手势，首先创建一个手势过渡管理的类，我这里是XWInteractiveTransition,因为无论哪一种转场，手势控制的实质都是一样的，我干脆就把这个手势过渡管理的类封装了一下，具体可以在.h文件里面查看，在接下来的三个转场效果中我们都可以便捷的是使用它 .m文件说明
//通过这个方法给控制器的View添加相应的手势
- (void)addPanGestureForViewController:(UIViewController *)viewController{
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
//将传入的控制器保存，因为要利用它触发转场操作
self.vc = viewController;
[viewController.view addGestureRecognizer:pan];
}
//关键的手势过渡的过程
- (void)handleGesture:(UIPanGestureRecognizer *)panGesture{
//persent是根据panGesture的移动距离获取的，这里就不说明了，可具体去代码中查看
switch (panGesture.state) {
case UIGestureRecognizerStateBegan:
//手势开始的时候标记手势状态，并开始相应的事件，它的作用在使用这个类的时候说明
self.interation = YES;
//手势开始是触发对应的转场操作，方法代码在后面
[self startGesture];
break;
case UIGestureRecognizerStateChanged:{
//手势过程中，通过updateInteractiveTransition设置转场过程进行的百分比，然后系统会根据百分比自动布局控件，不用我们控制了
[self updateInteractiveTransition:persent];
break;
}
case UIGestureRecognizerStateEnded:{
//手势完成后结束标记并且判断移动距离是否过半，过则finishInteractiveTransition完成转场操作，否者取消转场操作，转场失败
self.interation = NO;
if (persent > 0.5) {
[self finishInteractiveTransition];
}else{
[self cancelInteractiveTransition];
}
break;
}
default:
break;
}
}
//触发对应转场操作的代码如下，根据type(type是我自定义的枚举值)我们去判断是触发哪种操作，对于push和present由于要传入需要push和present的控制器，为了解耦，我用block把这个操作交个控制器去做了，让这个手势过渡管理者可以充分被复用
- (void)startGesture{
switch (_type) {
case XWInteractiveTransitionTypePresent:{
if (_presentConifg) {
_presentConifg();
}
}
break;
case XWInteractiveTransitionTypeDismiss:
[_vc dismissViewControllerAnimated:YES completion:nil];
break;
case XWInteractiveTransitionTypePush:{
if (_pushConifg) {
_pushConifg();
}
}
break;
case XWInteractiveTransitionTypePop:
[_vc.navigationController popViewControllerAnimated:YES];
break;
}
}
7、 手势过渡管理者就算完毕了，这个手势管理者可以用到其他任何的模态和导航控制器转场中，以后都不用在写了，现在把他用起来，在vc2和vc1中创建相应的手势过渡管理者，并放到相应的代理方法去返回它
//创建dismiss手势过渡管理者，present的手势过渡要在vc1中创建，因为present的手势是加载vc1的view上的，我选择通过代理吧vc1中创建的手势过渡管理者传过来
self.interactiveDismiss = [XWInteractiveTransition interactiveTransitionWithTransitionType:XWInteractiveTransitionTypeDismiss GestureDirection:XWInteractiveTransitionGestureDirectionDown];
[self.interactiveDismiss addPanGestureForViewController:self];
[_interactivePush addPanGestureForViewController:self.navigationController];
//返回dissmiss的手势过渡管理
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal: (id<UIViewControllerAnimatedTransitioning>)animator{
//在没有用手势触发的dismiss的时候需要传nil，否者无法点击dimiss，所以interation就是用来判断是否是手势触发转场的
return _interactiveDismiss.interation ? _interactiveDismiss : nil;
}
//返回present的手势管理，这个手势管理者是在vc1中创建的，我用代理传过来的
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForPresentation: (id<UIViewControllerAnimatedTransitioning>)animator{
XWInteractiveTransition *interactivePresent = [_delegate interactiveTransitionForPresent];
return interactivePresent.interation ? interactivePresent : nil;
}
8、 终于完成了，再来看一下效果，是不是还不错！
弹性pop
DEMO TWO
1、 创建动画过渡管理者的代码就不重复说明了，我仿造demo1，利用枚举创建了一个同时管理push和pop的管理者，然后动画的逻辑代码集中在doPushAnimation和doPopAnimation中，很多内容都在demo1中说明了，下面的注释就比较简单了，来看看
//Push动画逻辑
- (void)doPushAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
XWMagicMoveController *fromVC = (XWMagicMoveController *)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
XWMagicMovePushController *toVC = (XWMagicMovePushController *)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
//拿到当前点击的cell的imageView
XWMagicMoveCell *cell = (XWMagicMoveCell *)[fromVC.collectionView cellForItemAtIndexPath:fromVC.currentIndexPath];
UIView *containerView = [transitionContext containerView];
//snapshotViewAfterScreenUpdates 对cell的imageView截图保存成另一个视图用于过渡，并将视图转换到当前控制器的坐标
UIView *tempView = [cell.imageView snapshotViewAfterScreenUpdates:NO];
tempView.frame = [cell.imageView convertRect:cell.imageView.bounds toView: containerView];
//设置动画前的各个控件的状态
cell.imageView.hidden = YES;
toVC.view.alpha = 0;
toVC.imageView.hidden = YES;
//tempView 添加到containerView中，要保证在最前方，所以后添加
[containerView addSubview:toVC.view];
[containerView addSubview:tempView];
//开始做动画
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 usingSpringWithDamping:0.55 initialSpringVelocity:1 / 0.55 options:0 animations:^{
tempView.frame = [toVC.imageView convertRect:toVC.imageView.bounds toView:containerView];
toVC.view.alpha = 1;
} completion:^(BOOL finished) {
//tempView先隐藏不销毁，pop的时候还会用
tempView.hidden = YES;
toVC.imageView.hidden = NO;
//如果动画过渡取消了就标记不完成，否则才完成，这里可以直接写YES，如果有手势过渡才需要判断，必须标记，否则系统不会中动画完成的部署，会出现无法交互之类的bug
[transitionContext completeTransition:YES];
}];
}
//Pop动画逻辑
- (void)doPopAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
XWMagicMovePushController *fromVC = (XWMagicMovePushController *)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
XWMagicMoveController *toVC = (XWMagicMoveController *)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
XWMagicMoveCell *cell = (XWMagicMoveCell *)[toVC.collectionView cellForItemAtIndexPath:toVC.currentIndexPath];
UIView *containerView = [transitionContext containerView];
//这里的lastView就是push时候初始化的那个tempView
UIView *tempView = containerView.subviews.lastObject;
//设置初始状态
cell.imageView.hidden = YES;
fromVC.imageView.hidden = YES;
tempView.hidden = NO;
[containerView insertSubview:toVC.view atIndex:0];
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 usingSpringWithDamping:0.55 initialSpringVelocity:1 / 0.55 options:0 animations:^{
tempView.frame = [cell.imageView convertRect:cell.imageView.bounds toView:containerView];
fromVC.view.alpha = 0;
} completion:^(BOOL finished) {
//由于加入了手势必须判断
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
if ([transitionContext transitionWasCancelled]) {//手势取消了，原来隐藏的imageView要显示出来
//失败了隐藏tempView，显示fromVC.imageView
tempView.hidden = YES;
fromVC.imageView.hidden = NO;
}else{//手势成功，cell的imageView也要显示出来
//成功了移除tempView，下一次pop的时候又要创建，然后显示cell的imageView
cell.imageView.hidden = NO;
[tempView removeFromSuperview];
}
}];
}
2、 然后将这个动画过渡管理者和demo1中创建的手势过渡管理者分别放到正确的代理方法中，用起来就可以了
神奇移动
DEMO THREE
1、 直接看看doPushAnimation和doPopAnimation的动画逻辑，这次使用了CAGradientLayer给动画的过程增加了阴影
//Push动画逻辑
- (void)doPushAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
//还是使用截图大法来完成动画，不然还是会有奇妙的bug;
UIView *tempView = [fromVC.view snapshotViewAfterScreenUpdates:NO];
tempView.frame = fromVC.view.frame;
UIView *containerView = [transitionContext containerView];
//将将要动画的视图加入containerView
[containerView addSubview:toVC.view];
[containerView addSubview:tempView];
fromVC.view.hidden = YES;
[containerView insertSubview:toVC.view atIndex:0];
//设置AnchorPoint，并增加3D透视效果
[tempView setAnchorPointTo:CGPointMake(0, 0.5)];
CATransform3D transfrom3d = CATransform3DIdentity;
transfrom3d.m34 = -0.002;
containerView.layer.sublayerTransform = transfrom3d;
//增加阴影
CAGradientLayer *fromGradient = [CAGradientLayer layer];
fromGradient.frame = fromVC.view.bounds;
fromGradient.colors = @[(id)[UIColor blackColor].CGColor,
(id)[UIColor blackColor].CGColor];
fromGradient.startPoint = CGPointMake(0.0, 0.5);
fromGradient.endPoint = CGPointMake(0.8, 0.5);
UIView *fromShadow = [[UIView alloc]initWithFrame:fromVC.view.bounds];
fromShadow.backgroundColor = [UIColor clearColor];
[fromShadow.layer insertSublayer:fromGradient atIndex:1];
fromShadow.alpha = 0.0;
[tempView addSubview:fromShadow];
CAGradientLayer *toGradient = [CAGradientLayer layer];
toGradient.frame = fromVC.view.bounds;
toGradient.colors = @[(id)[UIColor blackColor].CGColor,
(id)[UIColor blackColor].CGColor];
toGradient.startPoint = CGPointMake(0.0, 0.5);
toGradient.endPoint = CGPointMake(0.8, 0.5);
UIView *toShadow = [[UIView alloc]initWithFrame:fromVC.view.bounds];
toShadow.backgroundColor = [UIColor clearColor];
[toShadow.layer insertSublayer:toGradient atIndex:1];
toShadow.alpha = 1.0;
[toVC.view addSubview:toShadow];
//动画吧
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
//翻转截图视图
tempView.layer.transform = CATransform3DMakeRotation(-M_PI_2, 0, 1, 0);
//给阴影效果动画
fromShadow.alpha = 1.0;
toShadow.alpha = 0.0;
} completion:^(BOOL finished) {
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
if ([transitionContext transitionWasCancelled]) {
//失败后记得移除截图，下次push又会创建
[tempView removeFromSuperview];
fromVC.view.hidden = NO;
}
}];
}}
//Pop动画逻辑
- (void)doPopAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *containerView = [transitionContext containerView];
//拿到push时候的的截图视图
UIView *tempView = containerView.subviews.lastObject;
[containerView addSubview:toVC.view];
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
//把截图视图翻转回来
tempView.layer.transform = CATransform3DIdentity;
fromVC.view.subviews.lastObject.alpha = 1.0;
tempView.subviews.lastObject.alpha = 0.0;
} completion:^(BOOL finished) {
if ([transitionContext transitionWasCancelled]) {
[transitionContext completeTransition:NO];
}else{
[transitionContext completeTransition:YES];
[tempView removeFromSuperview];
toVC.view.hidden = NO;
}
}];}
2、 最后用上去在加上手势就是这个样子啦
翻页效果
DEMO FOUR
1、 直接看看doPresentAnimation和doDismissAnimation的动画逻辑，这次使用了CASharpLayer和UIBezierPath
//Present动画逻辑
- (void)presentAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
//拿到控制器获取button的frame来设置动画的开始结束的路径
UINavigationController *fromVC = (UINavigationController *)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
XWCircleSpreadController *temp = fromVC.viewControllers.lastObject;
UIView *containerView = [transitionContext containerView];
[containerView addSubview:toVC.view];
//画两个圆路径
UIBezierPath *startCycle = [UIBezierPath bezierPathWithOvalInRect:temp.buttonFrame];
//通过如下方法计算获取在x和y方向按钮距离边缘的最大值，然后利用勾股定理即可算出最大半径
CGFloat x = MAX(temp.buttonFrame.origin.x, containerView.frame.size.width - temp.buttonFrame.origin.x);
CGFloat y = MAX(temp.buttonFrame.origin.y, containerView.frame.size.height - temp.buttonFrame.origin.y);
//勾股定理计算半径
CGFloat radius = sqrtf(pow(x, 2) + pow(y, 2));
//以按钮中心为圆心，按钮中心到屏幕边缘的最大距离为半径，得到转场后的path
UIBezierPath *endCycle = [UIBezierPath bezierPathWithArcCenter:containerView.center radius:radius startAngle:0 endAngle:M_PI * 2 clockwise:YES];
//创建CAShapeLayer进行遮盖
CAShapeLayer *maskLayer = [CAShapeLayer layer];
//设置layer的path保证动画后layer不会回弹
maskLayer.path = endCycle.CGPath;
//将maskLayer作为toVC.View的遮盖
toVC.view.layer.mask = maskLayer;
//创建路径动画
CABasicAnimation *maskLayerAnimation = [CABasicAnimation animationWithKeyPath:@"path"];
maskLayerAnimation.delegate = self;
//动画是加到layer上的，所以必须为CGPath，再将CGPath桥接为OC对象
maskLayerAnimation.fromValue = (__bridge id)(startCycle.CGPath);
maskLayerAnimation.toValue = (__bridge id)((endCycle.CGPath));
maskLayerAnimation.duration = [self transitionDuration:transitionContext];
maskLayerAnimation.delegate = self;
//设置淡入淡出
maskLayerAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[maskLayerAnimation setValue:transitionContext forKey:@"transitionContext"];
[maskLayer addAnimation:maskLayerAnimation forKey:@"path"];
}
//Dismiss动画逻辑
- (void)dismissAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UINavigationController *toVC = (UINavigationController *)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
XWCircleSpreadController *temp = toVC.viewControllers.lastObject;
UIView *containerView = [transitionContext containerView];
//画两个圆路径
CGFloat radius = sqrtf(containerView.frame.size.height * containerView.frame.size.height + containerView.frame.size.width * containerView.frame.size.width) / 2;
UIBezierPath *startCycle = [UIBezierPath bezierPathWithArcCenter:containerView.center radius:radius startAngle:0 endAngle:M_PI * 2 clockwise:YES];
UIBezierPath *endCycle = [UIBezierPath bezierPathWithOvalInRect:temp.buttonFrame];
//创建CAShapeLayer进行遮盖
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.fillColor = [UIColor greenColor].CGColor;
maskLayer.path = endCycle.CGPath;
fromVC.view.layer.mask = maskLayer;
//创建路径动画
CABasicAnimation *maskLayerAnimation = [CABasicAnimation animationWithKeyPath:@"path"];
maskLayerAnimation.delegate = self;
maskLayerAnimation.fromValue = (__bridge id)(startCycle.CGPath);
maskLayerAnimation.toValue = (__bridge id)((endCycle.CGPath));
maskLayerAnimation.duration = [self transitionDuration:transitionContext];
maskLayerAnimation.delegate = self;
maskLayerAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[maskLayerAnimation setValue:transitionContext forKey:@"transitionContext"];
[maskLayer addAnimation:maskLayerAnimation forKey:@"path"];
}
2、最后在animationDidStop的代理方法中处理到动画的完成逻辑，处理方式都类似
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
switch (_type) {
case XWCircleSpreadTransitionTypePresent:{
id<UIViewControllerContextTransitioning> transitionContext = [anim valueForKey:@"transitionContext"];
[transitionContext completeTransition:YES];
[transitionContext viewControllerForKey:UITransitionContextToViewKey].view.layer.mask = nil;
}
break;
case XWCircleSpreadTransitionTypeDismiss:{
id<UIViewControllerContextTransitioning> transitionContext = [anim valueForKey:@"transitionContext"];
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
if ([transitionContext transitionWasCancelled]) {
[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view.layer.mask = nil;
}
}
break;
}
}
3、 最后用上去在加上手势就是这个样子啦
扩散效果
总结
1、关于：self.modalPresentationStyle = UIModalPresentationCustom;我查看了视图层级后发现，如果使用了Custom，在present动画完成的时候，presentingView也就是demo one中的vc1的view会从containerView中移除，只是移除，并未销毁，此时还被持有着(dismiss后还得回来呢！)，如果设置custom，那么present完成后，它一直都在containerView中，只是在最后面，所以需不需要设置custom可以看动画完成后的情况，是否还需要看见presentingViewController，但是记住如果没有设置custom，在disMiss的动画逻辑中，要把它加回containerView中，不然就不在咯~！
2、感觉写了好多东西，其实只要弄懂了转场的逻辑，其实就只需要写动画的逻辑就行了，其他东西都是固定的，而且苹果提供的这种控制转场的方式可充分解耦，除了写的手势过渡管理可以拿到任何地方使用，所有的动画过渡管理者都可以很轻松的复用到其他转场中，都不用分是何种转场，demo没有写标签控制器的转场，实现方法也是完全类似的，大家可以尝试一下，四个demo的github地址：自定义转场动画demo
