前言
首先, push/pop 动效在iOS7.0以后系统就已经提供了相关的代理方法, 在代理方法中我们可以自定义切换动画.
自定义push,pop动画是由UINavigationController的代理方法中提供的.
用于实现自定义动画的代理(UINavigationControllerDelegate)方法如下:
- (nullable id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController
interactionControllerForAnimationController:(id <UIViewControllerAnimatedTransitioning>) animationController NS_AVAILABLE_IOS(7_0);
- (nullable id <UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController *)fromVC
toViewController:(UIViewController *)toVC NS_AVAILABLE_IOS(7_0);
1. 实现自定义push,pop动画
一般的自定义动画通过navigationController:animationControllerForOperation:fromViewController:toViewController:这个代理方法实现, 这个代理方法返回id<UIViewControllerAnimatedTransitioning>类型的对象, 也就是说, 只需要定义好实现UIViewControllerAnimatedTransitioning协议的一个类即可.
1. UIViewControllerAnimatedTransitioning协议
UIViewControllerAnimatedTransitioning协议定义如下所示, 不解释:
@protocol UIViewControllerAnimatedTransitioning <NSObject>
// 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;
@optional
// This is a convenience and if implemented will be invoked by the system when the transition context's completeTransition: method is invoked.
- (void)animationEnded:(BOOL) transitionCompleted;
@end
代码中实现这个协议时候思路是这样的, 整体上是继承的结构, 因为动画具体的动效效果可能有n种, 但是基本方法和判断都是相同的. 父类遵循协议并实现如上的几个代理, 父类实现几个类方法来快速创建对象, 并提供其它初始化方法; 父类完成基本的逻辑判断和方法调用, 子类继承父类, 具体实现动效效果. 由于Objective-C中没有抽象方法, 例子在父类中声明方法, 空实现, 子类重写父类相关的方法. 父类如下所示:
WHBaseAnimationTransitioning.h
#import <UIKit/UIKit.h>
#import "UIViewController+WHAnimationTransitioningSnapshot.h"
@interface WHBaseAnimationTransitioning : NSObject <UIViewControllerAnimatedTransitioning>
@property (nonatomic, strong, readwrite) UIPercentDrivenInteractiveTransition *interactivePopTransition;
/// 创建动画效果的实例对象并设置动画类型, push or pop
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType;
/// 创建动画效果的实例对象并设置动画类型和间隔时间
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType duration:(NSTimeInterval)duration;
/// 创建动画效果实例对象并设置动画类型/间隔时间/可交互属性
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType duration:(NSTimeInterval)duration interactivePopTransition:(UIPercentDrivenInteractiveTransition *)interactivePopTransition;
- (instancetype)initWithType:(UINavigationControllerOperation)transitionType duration:(NSTimeInterval)duration;
#pragma mark - 真正实现 push, pop 动画的方法, 具体实现交给子类
- (void)push:(id<UIViewControllerContextTransitioning>)transitionContext;
- (void)pop:(id<UIViewControllerContextTransitioning>)transitionContext;
- (void)pushEnded;
- (void)popEnded;
@end
WHBaseAnimationTransitioning.m
#import "WHBaseAnimationTransitioning.h"
/// 默认动画执行时间间隔
const static NSTimeInterval WHAnimationTransitioningDuration = 0.6;
@interface WHBaseAnimationTransitioning ()
@property (nonatomic, assign) NSTimeInterval duration;
@property (nonatomic, assign) UINavigationControllerOperation transitionType;
@end
@implementation WHBaseAnimationTransitioning
- (instancetype)init {
if (self = [self initWithType:UINavigationControllerOperationPush duration:WHAnimationTransitioningDuration]) {
}
return self;
}
// 主要的构造方法
- (instancetype)initWithType:(UINavigationControllerOperation)transitionType duration:(NSTimeInterval)duration {
if (self = [super init]) {
self.duration = duration;
self.transitionType = transitionType;
}
return self;
}
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType {
return [self transitionWithType:transitionType duration:WHAnimationTransitioningDuration];
}
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType
duration:(NSTimeInterval)duration {
return [self transitionWithType:transitionType duration:duration interactivePopTransition:nil];
}
+ (instancetype)transitionWithType:(UINavigationControllerOperation)transitionType duration:(NSTimeInterval)duration interactivePopTransition:(UIPercentDrivenInteractiveTransition *)interactivePopTransition {
WHBaseAnimationTransitioning *animationTransitioning = [[self alloc] initWithType:transitionType duration:duration];
animationTransitioning.interactivePopTransition = interactivePopTransition;
return animationTransitioning;
}
- (void)push:(id<UIViewControllerContextTransitioning>)transitionContext {}
- (void)pop:(id<UIViewControllerContextTransitioning>)transitionContext {}
- (void)pushEnded {}
- (void)popEnded {}
#pragma mark - UIViewControllerAnimatedTransitioning
- (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext {
return self.duration;
}
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext {
if (self.transitionType == UINavigationControllerOperationPush) {
[self push:transitionContext];
}
else if (self.transitionType == UINavigationControllerOperationPop) {
[self pop:transitionContext];
}
}
- (void)animationEnded:(BOOL) transitionCompleted {
if (!transitionCompleted) return;
if (self.transitionType == UINavigationControllerOperationPush) {
[self pushEnded];
}
else if (self.transitionType == UINavigationControllerOperationPop) {
[self popEnded];
}
}
@end
2. 具体实现动画
动画效果如下:
代码如下:
#import "WHBaseAnimationTransitioning.h"
@interface WHBackPriorViewAnimation : WHBaseAnimationTransitioning
@end
@implementation WHBackPriorViewAnimation
- (void)push:(id<UIViewControllerContextTransitioning>)transitionContext {
UIViewController * fromVc = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController * toVc = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
NSTimeInterval duration = [self transitionDuration:transitionContext];
CGRect bounds = [[UIScreen mainScreen] bounds];
fromVc.view.hidden = YES;
[[transitionContext containerView] addSubview:fromVc.snapshot];
[[transitionContext containerView] addSubview:toVc.view];
[[toVc.navigationController.view superview] insertSubview:fromVc.snapshot belowSubview:toVc.navigationController.view];
toVc.navigationController.view.transform = CGAffineTransformMakeTranslation(CGRectGetWidth(bounds), 0.0);
[UIView animateWithDuration:duration
delay:0
usingSpringWithDamping:1.0
initialSpringVelocity:0.0f
options:UIViewAnimationOptionCurveLinear
animations:^{
fromVc.snapshot.alpha = 0.3;
fromVc.snapshot.transform = CGAffineTransformMakeScale(0.965, 0.965);
toVc.navigationController.view.transform = CGAffineTransformMakeTranslation(0.0, 0.0);
}
completion:^(BOOL finished) {
fromVc.view.hidden = NO;
[fromVc.snapshot removeFromSuperview];
[toVc.snapshot removeFromSuperview];
[transitionContext completeTransition:YES];
}];
}
- (void)pop:(id<UIViewControllerContextTransitioning>)transitionContext {
UIViewController * fromVc = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController * toVc = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
NSTimeInterval duration = [self transitionDuration:transitionContext];
CGRect bounds = [[UIScreen mainScreen] bounds];
[fromVc.view addSubview:fromVc.snapshot];
fromVc.navigationController.navigationBar.hidden = YES;
fromVc.view.transform = CGAffineTransformMakeTranslation(0.0, 0.0);
toVc.view.hidden = YES;
toVc.snapshot.alpha = 0.3;
toVc.snapshot.transform = CGAffineTransformMakeScale(0.965, 0.965);
[[transitionContext containerView] addSubview:toVc.view];
[[transitionContext containerView] addSubview:toVc.snapshot];
[[transitionContext containerView] sendSubviewToBack:toVc.snapshot];
[UIView animateWithDuration:duration
delay:0
usingSpringWithDamping:1.0
initialSpringVelocity:0.1f
options:UIViewAnimationOptionCurveLinear
animations:^{
fromVc.view.transform = CGAffineTransformMakeTranslation(CGRectGetWidth(bounds), 0.0);
toVc.snapshot.alpha = 1.0;
toVc.snapshot.transform = CGAffineTransformIdentity;
}
completion:^(BOOL finished) {
toVc.navigationController.navigationBar.hidden = NO;
toVc.view.hidden = NO;
[fromVc.snapshot removeFromSuperview];
[toVc.snapshot removeFromSuperview];
fromVc.snapshot = nil;
// Reset toViewController's `snapshot` to nil
if (![transitionContext transitionWasCancelled]) {
toVc.snapshot = nil;
}
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
}
@end
到此为止, 已经成功实现自定义push, pop动画.
2. 实现可交互的pop动画
交互式的动画, 这个概念太大, 这里介绍的是使用手势pop动画的实现过程.
1. 动画效果
动画效果如下所示:
2. 实现过程
手势pop动画, 主要是要监听手势变化, 然后根据手势变化更新动画. 我的实现思路是, 在BaseViewController中给控制器添加手势并监听, 如果是右滑则开始执行pop动画, 具体代码如下所示:
// 判断是否是根控制器 并添加手势
if (self.navigationController != nil && self != self.navigationController.viewControllers.firstObject) {
UIPanGestureRecognizer *popRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePopRecognizer:)];
[self.view addGestureRecognizer:popRecognizer];
popRecognizer.delegate = self;
}
#pragma mark - UIPanGestureRecognizer handlers
// 实现监听手势变化的代理方法
- (void)handlePopRecognizer:(UIPanGestureRecognizer *)recognizer {
CGFloat progress = [recognizer translationInView:self.view].x / CGRectGetWidth(self.view.frame);
progress = MIN(1.0, MAX(0.0, progress));
if (recognizer.state == UIGestureRecognizerStateBegan) {
// Create a interactive transition and pop the view controller
self.interactivePopTransition = [[UIPercentDrivenInteractiveTransition alloc] init];
[self.navigationController popViewControllerAnimated:YES];
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
// Update the interactive transition's progress
[self.interactivePopTransition updateInteractiveTransition:progress];
} else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {
// Finish or cancel the interactive transition
if (progress > 0.25) {
[self.interactivePopTransition finishInteractiveTransition];
} else {
[self.interactivePopTransition cancelInteractiveTransition];
}
self.interactivePopTransition = nil;
}
}
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)recognizer {
return [recognizer velocityInView:self.view].x > 0;
}
BaseViewController中实现以上方法即可, 要想实现侧滑功能, 还需要实现NAVi的一个代理方法:navigationController:interactionControllerForAnimationController:, 在这个代理方法中返回遵循UIViewControllerInteractiveTransitioning协议的对象即可.
- (nullable id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController
interactionControllerForAnimationController:(WHBaseAnimationTransitioning *) animationController {
return animationController.interactivePopTransition;
}
至此, 手势实现pop效果已经实现完毕, 如有任何疑问, 欢迎交流.
另有其它几种动效效果, 详见github源码.
如果您觉得本文有用, 欢迎star支持一下 😃 .
源码地址: https://github.com/hell03W/SwitchControllerAnimation
后记
博文作者：hell03W
博文出处: http://my.oschina.net/whforever
github: https://github.com/hell03W
oschina: http://my.oschina.net/whforever
jianshu: http://www.jianshu.com/users/ea059360a6f6
本文版权归作者，欢迎转载，但须保留此段声明，并给出原文链接，谢谢合作！
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