内容简介:iOS-转场动画
记录iOS中常见Modal、Push转场动画的学习及实践
相关api的记录及介绍
/*这个接口用来提供切换上下文给开发者使用,包含了从哪个VC到哪个VC等各类信息*/ @protocol UIViewControllerContextTransitioning -(UIView *)containerView; VC切换所发生的view容器,开发者应该将切出的view移除,将切入的view加入到该view容器中。 -(UIViewController *)viewControllerForKey:(NSString *)key; 提供一个key,返回对应的VC。现在的SDK中key的选择只有UITransitionContextFromViewControllerKey和UITransitionContextToViewControllerKey两种,分别表示将要切出和切入的VC。 -(CGRect)initialFrameForViewController:(UIViewController *)vc; 某个VC的初始位置,可以用来做动画的计算。 -(CGRect)finalFrameForViewController:(UIViewController *)vc; 与上面的方法对应,得到切换结束时某个VC应在的frame。 -(void)completeTransition:(BOOL)didComplete; 向这个context报告切换已经完成。 /* 自定义转场动画中使用 */ /*这个接口负责切换的具体内容,也即“切换中应该发生什么”。开发者在做自定义切换效果时大部分代码会是用来实现这个接口*/ @protocol UIViewControllerAnimatedTransitioning -(NSTimeInterval)transitionDuration:(id < UIViewControllerContextTransitioning >)transitionContext; 系统给出一个切换上下文,我们根据上下文环境返回这个切换所需要的花费时间 -(void)animateTransition:(id < UIViewControllerContextTransitioning >)transitionContext; 在进行切换的时候将调用该方法,我们对于切换时的UIView的设置和动画都在这个方法中完成。 /* ViewController中调用 */ @protocol UIViewControllerTransitioningDelegate // 动画 -(id< UIViewControllerAnimatedTransitioning >)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source; -(id< UIViewControllerAnimatedTransitioning >)animationControllerForDismissedController:(UIViewController *)dismissed; // 交互 -(id< UIViewControllerInteractiveTransitioning >)interactionControllerForPresentation:(id < UIViewControllerAnimatedTransitioning >)animator; -(id< UIViewControllerInteractiveTransitioning >)interactionControllerForDismissal:(id < UIViewControllerAnimatedTransitioning >)animator; /* UIViewControllerInteractiveTransitioning 提供百分比控制交互切换*/ -(Float)completionSpeed 返回速度 1 - self.percentComplete; -(void)updateInteractiveTransition:(CGFloat)percentComplete 更新百分比,一般通过手势识别的长度之类的来计算一个值,然后进行更新。之后的例子里会看到详细的用法 -(void)cancelInteractiveTransition 报告交互取消,返回切换前的状态 –(void)finishInteractiveTransition 报告交互完成,更新到切换后的状态
-
注意点
locationInView:获取到的是手指点击屏幕实时的坐标点;
translationInView:获取到的是手指移动后,在相对坐标中的偏移量
Modal
注意:当我们在被modal出的控制器中,向self发送dismissViewController的方法时,这个消息,会被直接转发到显示它的VC中去
Present
BouncePresentTransition的具体实现
#import <Foundation/Foundation.h> #import <UIKit/UIKit.h> @interface SPBouncePresentTransition : NSObject<UIViewControllerAnimatedTransitioning> @end
#import "SPBouncePresentTransition.h" @implementation SPBouncePresentTransition - (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{ return 0.8f; } - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{ // 获取相关ViewController UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; // UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; CGRect bounds = [UIScreen mainScreen].bounds; // 设置被modal出界面view的frame CGRect finalFrame = [transitionContext finalFrameForViewController:toVC]; // 设置目标界面frame的offset,即初始位置 toVC.view.frame = CGRectOffset(finalFrame, 0, bounds.size.height); // 取出containerView,将目标vc的view进行添加 UIView *containerView = [transitionContext containerView]; [containerView addSubview:toVC.view]; // 设置view的frame动画效果 [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 usingSpringWithDamping:0.6 initialSpringVelocity:0.0 options:UIViewAnimationOptionCurveLinear animations:^{ toVC.view.frame = finalFrame; } completion:^(BOOL finished) { // 提交transion完成 [transitionContext completeTransition:YES]; }]; } @end
在viewcontroller中如何使用
1.遵守 UIViewControllerTransitioningDelegate
协议
2.设置modal的vc的 transitioningDelegate
属性
3.实现代理方法
-(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
具体可参照如下代码
#pragma mark - Transition - (void)testForModalTransition{ SPModalViewController *vc = [[SPModalViewController alloc] init]; vc.transitioningDelegate = self;// 设置代理 vc.dismissAction = ^{ [self dismissViewControllerAnimated:YES completion:nil]; }; [self presentViewController:vc animated:YES completion:nil]; } // 代理方法 // init /* self.bouncePresent = [[SPBouncePresentTransition alloc]init]; */ -(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{ return self.bouncePresent; }
效果如下
Dismiss
滑动效果的转场实现
需要注意的是,务必同时实现两个代理方法
触发顺序,为 动画类->交互类
,系统会优先处理 animationControllerForDismissedController
方法,如果有,则dismiss操作均为自定义dismissTransition(demo中的transitionDuration已经设置为1.5s,效果可如gif动图所示),如果没有设置,那么则为系统的dismiss动画。
// 动画类 - (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
// 交互类 - (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator
具体可参照如下代码
1.NormalDismiss
#import <Foundation/Foundation.h> #import <UIKit/UIKit.h> @interface SPNormalDismissTransition : NSObject<UIViewControllerAnimatedTransitioning> @end
#import "SPNormalDismissTransition.h" @implementation SPNormalDismissTransition - (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{ return 1.5f; } - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{ UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; CGRect initialFrame = [transitionContext initialFrameForViewController:fromVC]; CGRect finalFrame = CGRectOffset(initialFrame, 0, [UIScreen mainScreen].bounds.size.height); UIView *containerView = [transitionContext containerView];// 承载当前活动vc的view的containerView [containerView addSubview:toVC.view]; [containerView sendSubviewToBack:toVC.view];// 将视图置于下层 [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{ fromVC.view.frame = finalFrame; } completion:^(BOOL finished) { [transitionContext completeTransition:![transitionContext transitionWasCancelled]]; }]; } @end
2.SwipeTransition
#import <UIKit/UIKit.h> @interface SPPercentSwipeTransition : UIPercentDrivenInteractiveTransition @property (nonatomic, assign) BOOL interacting;// 用来判断是否处理交互 - (void)addSwipeTransition2viewController:(UIViewController *)viewController;// 传入要添加panRecognizer的viewController @end
#import "SPPercentSwipeTransition.h" @interface SPPercentSwipeTransition() @property (nonatomic, weak) UIViewController *presenedController;// 当前被modal出的控制器 注意weak的使用,强引用造成无法释放 @property (nonatomic, assign) BOOL canEndTransition;// 当超过屏幕高度的1/4时,我们认为交互可以结束 @end @implementation SPPercentSwipeTransition - (void)addSwipeTransition2viewController:(UIViewController *)viewController{ self.presenedController = viewController; [self addRecognizer2View:viewController.view]; } - (void)addRecognizer2View:(UIView *)view{ UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] init]; [view addGestureRecognizer:pan]; [pan addTarget:self action:@selector(handleRecognizer:)]; } - (void)handleRecognizer:(UIPanGestureRecognizer *)recognizer{ CGRect screenBounds = [UIScreen mainScreen].bounds; CGPoint point = [recognizer translationInView:recognizer.view.superview];// translationInView switch (recognizer.state) { case UIGestureRecognizerStateBegan: self.interacting = YES; [self.presentingController dismissViewControllerAnimated:YES completion:nil]; break; case UIGestureRecognizerStateChanged: { CGFloat actionPoint = point.y/(screenBounds.size.height /2);// 有效距离为屏幕高度的一半 actionPoint = fminf(fmaxf(actionPoint, 0.0), 1.0); self.canEndTransition = actionPoint > 0.5;// 滑动超过屏幕高度的1/4则可完成转场 [self updateInteractiveTransition:actionPoint]; } break; case UIGestureRecognizerStateEnded: case UIGestureRecognizerStateCancelled: { self.interacting = NO; if (self.canEndTransition) { [self finishInteractiveTransition]; } else if (!self.canEndTransition || recognizer.state == UIGestureRecognizerStateCancelled) { [self cancelInteractiveTransition]; } } break; default: break; } } - (CGFloat)completionSpeed{// 返回转场的速度 return 1 - self.percentComplete; }
效果如下
SemiModal
实现一个常见的semi半挂式modal,将我们上述的AnimationTransition(present)、NormalDismiss部分稍作处理即可
效果如下:
首先分析实现思路:
1.semi部分,在 bouncePresentTransition
中的toVC的view进行圆角处理,同时设置它在containerView中的frame为目标样式
2.背景部分,将当前fromVC的view进行截图,添加到转场容器 containerView
中,然后改变它的 transform
中的scale属性,进行等比例缩放,同时将底层viewController的view进行隐藏处理
3.因为上文中,我们已经处理了基于 UIPercentDrivenInteractiveTransition
的 swipeTransition
,所以不需要再关心百分比变化
4.上文中处理的 normalDismiss
,只是简单的对视图进行了切换,因为考虑到semi的样式会对底层viewController的view进行隐藏处理,所以我们需要特别注意,在transition完成时,要将目标vc的view显示出来
思路有了,那么接下来就是实现,具体请看代码:
截图方法
- (UIImage *)getSnapShotFromView:(UIView *)view{ CGRect rect = view.bounds; UIGraphicsBeginImageContextWithOptions(rect.size, false, 0); [view.layer renderInContext:UIGraphicsGetCurrentContext()]; UIImage *snapShot = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return snapShot; }
改造的bouncePresent
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{ // 获取相关ViewController UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; CGRect bounds = [UIScreen mainScreen].bounds; // 设置被modal出界面view的frame // CGRect finalFrame = [transitionContext finalFrameForViewController:toVC]; // -- semi效果 -- CGRect finalFrame = CGRectMake(0, bounds.size.height/3, bounds.size.width, bounds.size.height); // 设置目标界面frame的offset,即初始位置 toVC.view.frame = CGRectOffset(finalFrame, 0, bounds.size.height); // -- semi效果 -- toVC.view.layer.cornerRadius = 15; [toVC.view.layer masksToBounds]; UIImageView *snapView = [[UIImageView alloc] initWithImage:[self getSnapShotFromView:fromVC.view]]; snapView.frame = fromVC.view.bounds; snapView.tag = 404;//标记一下 // 将fromvc的view隐藏掉 fromVC.view.hidden = YES; // 取出containerView(视图管理容器),将目标vc的view进行添加 UIView *containerView = [transitionContext containerView]; // -- semi效果 -- [containerView addSubview:snapView]; // 注意添加顺序 [containerView addSubview:toVC.view]; // 设置view的frame动画效果 [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 usingSpringWithDamping:0.6 initialSpringVelocity:0.0 options:UIViewAnimationOptionCurveLinear animations:^{ toVC.view.frame = finalFrame; snapView.transform = CGAffineTransformMakeScale(0.85, 0.85); } completion:^(BOOL finished) { // 提交transion完成 if ([transitionContext transitionWasCancelled]) { [transitionContext completeTransition:NO]; [snapView removeFromSuperview]; fromVC.view.hidden = NO; // 注意隐藏操作 }else{ [transitionContext completeTransition:YES]; } }]; }
改造的normalDismiss
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{ UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; CGRect initialFrame = [transitionContext initialFrameForViewController:fromVC]; CGRect finalFrame = CGRectOffset(initialFrame, 0, [UIScreen mainScreen].bounds.size.height); UIView *containerView = [transitionContext containerView];// 承载当transitionview的containerView UIView *snapView = nil;// 取出截图 tag = 404 for (UIView *sub in containerView.subviews) { if (sub.tag == 404) { snapView = sub; break; } } [containerView addSubview:toVC.view]; [containerView sendSubviewToBack:toVC.view];// 将视图置于下层 [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{ fromVC.view.frame = finalFrame; snapView.transform = CGAffineTransformIdentity; } completion:^(BOOL finished) { BOOL transitionComplete = ![transitionContext transitionWasCancelled]; [transitionContext completeTransition:transitionComplete]; if (transitionComplete) { toVC.view.hidden = NO; [snapView removeFromSuperview]; }else{ toVC.view.hidden = YES; } }]; }
Push&Pop
Push
在viewcontroller中如何使用
1.遵守 UINavigationControllerDelegate
协议
2.设置 viewcontroller.navigationController.delegate
的代理
3.实现代理方法
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC
这里需要 特别注意 一点,对于Push和Pop,都会在此方法中返回,需要我们对 operation
进行类型判断,返回正确类型的自定义transition
同时要考虑一种特殊情况,就是自己并非第一层viewController时,从自身pop出去的情况
if (fromVC == self && operation == UINavigationControllerOperationPop) {// 从自己pop出去 return nil; }
(我们可以发现,Push同上文中提到的Modal的处理方式一致,只是遵守的协议不同)
先看效果
分析一下思路:
1.将点击的Cell中的imageView,传入到转场容器container中,转换其坐标、截图并添加(注意同toVC.view的添加顺序),我们命名为snapView
2.获取fromVC中的目标图片位置,设置为snapview的终点frame
大概看一下我们如何实现,写一下几个比较关键的地方
// 1.fromVC,处理点击CollectionView的点击事件 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ PushCell *cell = (PushCell *)[collectionView cellForItemAtIndexPath:indexPath]; self.transImgView = cell.transImg; SPGakkiViewController *gakki = [[SPGakkiViewController alloc] init]; [self.navigationController pushViewController:gakki animated:YES]; } // 2.transition中的写法 SPGakkiViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; SPPushViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; // 获取视图容器 UIView *containerView = [transitionContext containerView]; // 获取需要变换的视图 UIImageView *transImgView = fromVC.transImgView; UIView *snapView = [transImgView snapshotViewAfterScreenUpdates:NO]; snapView.frame = [transImgView convertRect:transImgView.bounds toView:containerView]; // 先隐藏视图 toVC.showContent = NO; [containerView addSubview:toVC.view]; [containerView addSubview:snapView]; // 动画部分 [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:1/0.6 options:UIViewAnimationOptionCurveEaseInOut animations:^{ snapView.frame = toVC.targetFrame; } completion:^(BOOL finished) { snapView.hidden = YES; toVC.showContent = YES; [snapView removeFromSuperview]; [transitionContext completeTransition:![transitionContext transitionWasCancelled]]; }];
Pop
效果如下
如果一路写到这里,想必已经明白转场动画的基本使用,所以我们不再赘述,只附效果的实现代码
SPPushViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; SPGakkiViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; // 获取视图容器 UIView *containerView = [transitionContext containerView]; [containerView addSubview:toVC.view]; toVC.view.alpha = 0; // 截图 UIView *snapView = [fromVC.imageView snapshotViewAfterScreenUpdates:NO]; // 隐藏 fromVC.showContent = NO; // 目标位置 CGRect startFrame = fromVC.targetFrame; CGRect targetFrame = [toVC.transImgView convertRect:toVC.transImgView.bounds toView:containerView]; snapView.frame = startFrame; [containerView addSubview:snapView]; // 开始动画 [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:1/0.6 options:UIViewAnimationOptionCurveEaseInOut animations:^{ snapView.frame = targetFrame; snapView.alpha = 0; toVC.view.alpha = 1; } completion:^(BOOL finished) { snapView.hidden = YES; [snapView removeFromSuperview]; [transitionContext completeTransition:![transitionContext transitionWasCancelled]]; }];
注意!注意!注意! [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
务必在动画结束时上报转场结束状态(此处手动鲜血红)
返回手势
只需要我们在之前写的 percentSwipeTransition
中稍加改造即可,我们将它稍加封装,代码如下
#import <UIKit/UIKit.h> typedef NS_ENUM(NSInteger,SPTransitionType) { SPTransitionTypePush, SPTransitionTypeModal }; @interface SPPercentSwipeTransition : UIPercentDrivenInteractiveTransition @property (nonatomic, assign) BOOL interacting; - (void)addSwipeTransition2viewController:(UIViewController *)viewController withType:(SPTransitionType)type; @end
#import "SPPercentSwipeTransition.h" @interface SPPercentSwipeTransition() @property (nonatomic, weak) UIViewController *presentingController; @property (nonatomic, assign) BOOL canEndTransition; @property (nonatomic, assign) SPTransitionType currentType; @end @implementation SPPercentSwipeTransition - (void)addSwipeTransition2viewController:(UIViewController *)viewController withType:(SPTransitionType)type{ self.currentType = type; [self addSwipeTransition2viewController:viewController]; } - (void)addSwipeTransition2viewController:(UIViewController *)viewController{ self.presentingController = viewController; [self addRecognizer2View:viewController.view]; } - (void)addRecognizer2View:(UIView *)view{ UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] init]; [view addGestureRecognizer:pan]; [pan addTarget:self action:@selector(handleRecognizer:)]; } - (void)handleRecognizer:(UIPanGestureRecognizer *)recognizer{ switch (recognizer.state) { case UIGestureRecognizerStateBegan: self.interacting = YES; [self moveBackWithTransitionType:_currentType]; break; case UIGestureRecognizerStateChanged: [self handleTransitionWithType:_currentType andRecognizer:recognizer]; break; case UIGestureRecognizerStateEnded: case UIGestureRecognizerStateCancelled: { self.interacting = NO; if (self.canEndTransition) { [self finishInteractiveTransition]; } else if (!self.canEndTransition || recognizer.state == UIGestureRecognizerStateCancelled) { [self cancelInteractiveTransition]; } } break; default: break; } } - (void)moveBackWithTransitionType:(SPTransitionType)type{ switch (type) { case SPTransitionTypeModal: [self.presentingController dismissViewControllerAnimated:YES completion:nil]; break; case SPTransitionTypePush: [self.presentingController.navigationController popViewControllerAnimated:YES]; break; } } - (void)handleTransitionWithType:(SPTransitionType)type andRecognizer:(UIPanGestureRecognizer *)recognizer{ CGRect screenBounds = [UIScreen mainScreen].bounds; CGPoint point = [recognizer translationInView:recognizer.view.superview];// translationInView switch (type) { case SPTransitionTypePush: { CGFloat percent = point.x/(screenBounds.size.width /2);// 有效距离为屏幕宽度的一半 percent = fminf(fmax(percent, 0.0), 1.0); self.canEndTransition = percent > 0.5;// 活动超过屏幕宽度的1/4则可完成转场 [self updateInteractiveTransition:percent]; } break; case SPTransitionTypeModal: { CGFloat actionPoint = point.y/(screenBounds.size.height /2);// 有效距离为屏幕高度的一半 actionPoint = fminf(fmaxf(actionPoint, 0.0), 1.0); self.canEndTransition = actionPoint > 0.5;// 滑动超过屏幕高度的1/4则可完成转场 [self updateInteractiveTransition:actionPoint]; } break; } } - (CGFloat)completionSpeed{ return 1 - self.percentComplete; } @end
因为加入了手势处理,所以我们需要将Pop中上报转场完成的地方稍加改动
考虑手势取消转场的情况,取消时,将fromVC的内容再次显示即可
// 开始动画 [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:1/0.6 options:UIViewAnimationOptionCurveEaseInOut animations:^{ snapView.frame = targetFrame; snapView.alpha = 0; toVC.view.alpha = 1; } completion:^(BOOL finished) { BOOL completeTransiton = ![transitionContext transitionWasCancelled]; snapView.hidden = YES; if (!completeTransiton) fromVC.showContent = YES; [snapView removeFromSuperview]; [transitionContext completeTransition:completeTransiton]; }];
看一下我们的最终效果
以上所述就是小编给大家介绍的《iOS-转场动画》,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持!
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