首先，支持并感谢@wazrx 的 http://www.jianshu.com/p/45434f73019e和@onevcat 的https://onevcat.com/2013/10/vc-transition-in-ios7/ 对于转场动画的讲解和实现，非常详细，本人也是看过他们的文章后受的启发，快速实现了基于本项目需求的转场动画效果。
效果如下：（gif是我们的美术大师帮忙做的演示动效，实际的效果要比这个好，可通过文章最后链接下载我们的app：柠檬跑步，查看效果）
地图切换.gif
我的需求是两个页面push、pop之间的切换，所以自定义了push的转场动画，首先需要个遵循<UIViewControllerAnimatedTransitioning>协议的管理对象，并实现其两个方法：
XWCircleSpreadTransition.h
#import <UIKit/UIKit.h>
typedef NS_ENUM(NSUInteger, XWCircleSpreadTransitionType) {
XWCircleSpreadTransitionTypePush = 0,
XWCircleSpreadTransitionTypePop
};
@interface XWCircleSpreadTransition : NSObject<UIViewControllerAnimatedTransitioning>
@property (nonatomic, assign) XWCircleSpreadTransitionType type;
+ (instancetype)transitionWithTransitionType:(XWCircleSpreadTransitionType)type;
- (instancetype)initWithTransitionType:(XWCircleSpreadTransitionType)type;@endXWCircleSpreadTransition.m
#import "XWCircleSpreadTransition.h"
@implementation XWCircleSpreadTransition
+ (instancetype)transitionWithTransitionType:(XWCircleSpreadTransitionType)type{
return [[self alloc] initWithTransitionType:type];
}
- (instancetype)initWithTransitionType:(XWCircleSpreadTransitionType)type{
self = [super init];
if (self) {
_type = type;
}
return self;
}
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
return 0.7;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
switch (_type) {
case XWCircleSpreadTransitionTypePush:
[self presentAnimation:transitionContext];
break;
case XWCircleSpreadTransitionTypePop:
[self dismissAnimation:transitionContext];
break;
}
}
- (void)dismissAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIView *containerView = [transitionContext containerView];
[containerView insertSubview:toVC.view atIndex:0]; //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.mapBtnFrame];
UIBezierPath *endCycle = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 0, 0)]; //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"];
}
- (void)presentAnimation:(id<UIViewControllerContextTransitioning>)transitionContext{ UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; UIView *containerView = [transitionContext containerView];
[containerView addSubview:toVC.view]; //画两个圆路径// UIBezierPath *startCycle = [UIBezierPath bezierPathWithOvalInRect:fromVC.mapBtnFrame];
UIBezierPath *startCycle = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 0, 0)]; CGFloat x = MAX(100, containerView.frame.size.width - 100); CGFloat y = MAX(100, containerView.frame.size.height - 100); CGFloat radius = sqrtf(pow(x, 2) + pow(y, 2)); 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];
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;
maskLayerAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[maskLayerAnimation setValue:transitionContext forKey:@"transitionContext"];
[maskLayer addAnimation:maskLayerAnimation forKey:@"path"];
}
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
switch (_type) {
case XWCircleSpreadTransitionTypePush:{
id<UIViewControllerContextTransitioning> transitionContext = [anim valueForKey:@"transitionContext"]; [transitionContext completeTransition:YES];
UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];
toView.layer.mask = nil;
UIViewController *vc = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; vc.view.layer.mask = nil; }
break;
case XWCircleSpreadTransitionTypePop:{
id<UIViewControllerContextTransitioning> transitionContext = [anim valueForKey:@"transitionContext"];
[transitionContext completeTransition:YES];
UIViewController *vc = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
vc.view.layer.mask = nil; }
break;
}
}
@end剩下的就是在ViewControllerA中实现代理<UINavigationControllerDelegate>中的animationControllerForOperation：
#pragma mark -
#pragma mark - UINavigation Delegate
-(id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC {
if (fromVC == self) {
return [XWCircleSpreadTransition transitionWithTransitionType:XWCircleSpreadTransitionTypePush];
}
if (toVC == self) {
return [XWCircleSpreadTransition transitionWithTransitionType:XWCircleSpreadTransitionTypePop];
}
return nil;
}到此，这个简单的转场动画已经实现完毕，而且动画效果可以自定义成自己想要的展现形式。