iOS7之定制ViewController切换效果

在iOS5和iOS6前，View Controller的切换主要有4种：

• 1. Push/Pop，NavigationViewController常干的事儿
• 2. Tab，TabViewController点击
• 3. PResent Modal，调用ViewController的presentViewController:animated:completion:方法
• 4. Add ChildViewController，调用- (void)addChildViewController:(UIViewController *)childController方法

在使用Add ChildViewController的方式时，一般使用transitionFromViewController:toViewController:…的Animation block中可以实现一些简单的切换效果，这样做有2大不足：

• 1. 代码高度耦合，VC切换部分的代码直接写在container中，难以分离重用；
• 2. 支持的切换效果比较有限，因为其只能使用UIView动画来切换，管理起来也略显麻烦

于是，苹果在iOS7中引入了一些新的API来帮助开发者更容易，更松耦合地定义ViewController的转换效果。
知识点
用法 从上面的知识点图中可以看出，新的API主要提供了2种VC切换的方式，一种是动画式切换，即定义一种从一个VC到另一个VC的动画效果，切换的时候自动播放，第二种是交互式切换，这种方式同样需要定义动画效果，只是这个动画效果会根据跟随交互式手势来切换VC并同时播放动画效果。 这两种方式的用法略有不同。
动画式切换

• 首先定义一个动画类实现接口UIViewControllerAnimatedTransitioning， 实现接口的2个方法，一个是动画效果的时间，一个是动画效果（- (void)animateTransition:(id )transitionContext ），实现动画效果时可以从参数transitionContext中获取到切换时的上下文信息，比方说从哪个VC切换到哪个VC等。
• 在需切换的VC中实现UIViewControllerTransitioningDelegate，并实现animationController*方法，返回一个步骤1定义的动画变量。
• 调用展现VC切换方法，presentViewController等。

交互式切换

• 定义一个类实现接口UIViewControllerInteractiveTransitioning，iOS7提供了一个默认的基于百分比的动画实现UIPercentDrivenInteractiveTransition，大家不想太麻烦可以直接扩展这个类。该类需要绑定需要实现手势控制的VC，同时把手势操作添加到该VC上，然后在处理手势动作的时候，调用接口中的方法去更新当前的动画进度。
• 定以切换时的动画效果类。和动画式切换的方式一致
• 在需切换的VC中实现UIViewControllerTransitioningDelegate，实现interactiveController方法，返回步骤1定义的类，实现animationController方法返回步骤2定义的动画效果。

实战 下图是我实现的一个VC切换的效果图，（注：App图片是网上随便找的，不代表个人喜好：）
实现代码： VC跳入动画的代码:

Object-c代码  

1. -(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext  
2. {  
3.     return 0.5f;  
4. }  
5.   
6. -(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext  
7. {  
8.   
9.     //Create the differents 3D animations  
10.     CATransform3D viewFromTransform;  
11.     CATransform3D viewToTransform;  
12.       
13.     UIView *generalContentView = [transitionContext containerView];  
14.     UIView *fromView = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view;  
15.     UIView *toView = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;  
16.   
17.       
18.     viewFromTransform = CATransform3DMakeRotation(ROTATION_ANGLE, 0.0, 1.0, 0.0);  
19.     viewToTransform = CATransform3DMakeRotation(-ROTATION_ANGLE, 0.0, 1.0, 0.0);  
20.     [toView.layer setAnchorPoint:CGPointMake(0, 0.5)];  
21.     [fromView.layer setAnchorPoint:CGPointMake(1, 0.5)];  
22.       
23. //    [generalContentView setTransform:CGAffineTransformMakeTranslation(generalContentView.frame.size.width/2.0, 0)];  
24.       
25.     viewFromTransform.m34 = PERSPECTIVE;  
26.     viewToTransform.m34 = PERSPECTIVE;  
27.       
28.     toView.layer.transform = viewToTransform;  
29.       
30.   
31.     //Add the to- view  
32.     [generalContentView addSubview:toView];  
33.       
34.     [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{  
35.         [generalContentView setTransform:CGAffineTransformMakeTranslation(-generalContentView.frame.size.width/2.0, 0)];  
36.           
37.         fromView.layer.transform = viewFromTransform;  
38.         toView.layer.transform = CATransform3DIdentity;  
39.           
40.     } completion:^(BOOL finished) {  
41.           
42.         //Set the final position of every elements transformed  
43.         [generalContentView setTransform:CGAffineTransformIdentity];  
44.         fromView.layer.transform = CATransform3DIdentity;  
45.         toView.layer.transform = CATransform3DIdentity;  
46.         [fromView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];  
47.         [toView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];  
48.           
49.           
50.         if ([transitionContext transitionWasCancelled]) {  
51.             [toView removeFromSuperview];  
52.         } else {  
53.             [fromView removeFromSuperview];  
54.         }  
55.           
56.         // inform the context of completion  
57.         [transitionContext completeTransition:![transitionContext transitionWasCancelled]];  
58.           
59.     }];  
60. }  

-(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{    return 0.5f;}-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{    //Create the differents 3D animations    CATransform3D viewFromTransform;    CATransform3D viewToTransform;        UIView *generalContentView = [transitionContext containerView];    UIView *fromView = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view;    UIView *toView = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;        viewFromTransform = CATransform3DMakeRotation(ROTATION_ANGLE, 0.0, 1.0, 0.0);    viewToTransform = CATransform3DMakeRotation(-ROTATION_ANGLE, 0.0, 1.0, 0.0);    [toView.layer setAnchorPoint:CGPointMake(0, 0.5)];    [fromView.layer setAnchorPoint:CGPointMake(1, 0.5)];    //    [generalContentView setTransform:CGAffineTransformMakeTranslation(generalContentView.frame.size.width/2.0, 0)];        viewFromTransform.m34 = PERSPECTIVE;    viewToTransform.m34 = PERSPECTIVE;        toView.layer.transform = viewToTransform;        //Add the to- view    [generalContentView addSubview:toView];        [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{        [generalContentView setTransform:CGAffineTransformMakeTranslation(-generalContentView.frame.size.width/2.0, 0)];                fromView.layer.transform = viewFromTransform;        toView.layer.transform = CATransform3DIdentity;            } completion:^(BOOL finished) {                //Set the final position of every elements transformed        [generalContentView setTransform:CGAffineTransformIdentity];        fromView.layer.transform = CATransform3DIdentity;        toView.layer.transform = CATransform3DIdentity;        [fromView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];        [toView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];                        if ([transitionContext transitionWasCancelled]) {            [toView removeFromSuperview];        } else {            [fromView removeFromSuperview];        }                // inform the context of completion        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];            }];}

手势交互代码：

Object-c代码  

1. -(void)wireToViewController:(UIViewController *)viewController  
2. {  
3.     self.presentingVC = viewController;  
4.     [self prepareGestureRecognizerInView:viewController.view];  
5. }  
6.   
7. - (void)prepareGestureRecognizerInView:(UIView*)view {  
8.     UIPanGestureRecognizer *gesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];  
9.     [view addGestureRecognizer:gesture];  
10. }  
11.   
12. -(CGFloat)completionSpeed  
13. {  
14.     return 1 - self.percentComplete;  
15. }  
16.   
17. - (void)handleGesture:(UIPanGestureRecognizer *)gestureRecognizer {  
18.     CGPoint translation = [gestureRecognizer translationInView:gestureRecognizer.view.superview];  
19.     switch (gestureRecognizer.state) {  
20.         case UIGestureRecognizerStateBegan:  
21.             // 1. Mark the interacting flag. Used when supplying it in delegate.  
22.             self.interacting = YES;  
23.             [self.presentingVC dismissViewControllerAnimated:YES completion:nil];  
24.             break;  
25.         case UIGestureRecognizerStateChanged: {  
26.             // 2. Calculate the percentage of guesture  
27.             CGFloat fraction = -translation.x / 300.0;  
28.             //Limit it between 0 and 1  
29.             fraction = fminf(fmaxf(fraction, 0.0), 1.0);  
30.             self.shouldComplete = (fraction > 0.5);  
31.               
32.             [self updateInteractiveTransition:fraction];  
33.             break;  
34.         }  
35.         case UIGestureRecognizerStateEnded:  
36.         case UIGestureRecognizerStateCancelled: {  
37.             // 3. Gesture over. Check if the transition should happen or not  
38.             self.interacting = NO;  
39.             if (!self.shouldComplete || gestureRecognizer.state == UIGestureRecognizerStateCancelled) {  
40.                 [self cancelInteractiveTransition];  
41.             } else {  
42.                 [self finishInteractiveTransition];  
43.             }  
44.             break;  
45.         }  
46.         default:  
47.             break;  
48.     }  
49. }  

-(void)wireToViewController:(UIViewController *)viewController{    self.presentingVC = viewController;    [self prepareGestureRecognizerInView:viewController.view];}- (void)prepareGestureRecognizerInView:(UIView*)view {    UIPanGestureRecognizer *gesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];    [view addGestureRecognizer:gesture];}-(CGFloat)completionSpeed{    return 1 - self.percentComplete;}- (void)handleGesture:(UIPanGestureRecognizer *)gestureRecognizer {    CGPoint translation = [gestureRecognizer translationInView:gestureRecognizer.view.superview];    switch (gestureRecognizer.state) {        case UIGestureRecognizerStateBegan:            // 1. Mark the interacting flag. Used when supplying it in delegate.            self.interacting = YES;            [self.presentingVC dismissViewControllerAnimated:YES completion:nil];            break;        case UIGestureRecognizerStateChanged: {            // 2. Calculate the percentage of guesture            CGFloat fraction = -translation.x / 300.0;            //Limit it between 0 and 1            fraction = fminf(fmaxf(fraction, 0.0), 1.0);            self.shouldComplete = (fraction > 0.5);                        [self updateInteractiveTransition:fraction];            break;        }        case UIGestureRecognizerStateEnded:        case UIGestureRecognizerStateCancelled: {            // 3. Gesture over. Check if the transition should happen or not            self.interacting = NO;            if (!self.shouldComplete || gestureRecognizer.state == UIGestureRecognizerStateCancelled) {                [self cancelInteractiveTransition];            } else {                [self finishInteractiveTransition];            }            break;        }        default:            break;    }}

根据手势3D切换的动画代码：

Object-c代码  

1. -(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext  
2. {  
3.     return 0.5f;  
4. }  
5.   
6. -(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext  
7. {  
8.   
9.     //Create the differents 3D animations  
10.     CATransform3D viewFromTransform;  
11.     CATransform3D viewToTransform;  
12.       
13.     UIView *generalContentView = [transitionContext containerView];  
14.     UIView *fromView = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view;  
15.     UIView *toView = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;  
16.   
17.       
18.     viewFromTransform = CATransform3DMakeRotation(ROTATION_ANGLE, 0.0, 1.0, 0.0);  
19.     viewToTransform = CATransform3DMakeRotation(-ROTATION_ANGLE, 0.0, 1.0, 0.0);  
20.     [toView.layer setAnchorPoint:CGPointMake(0, 0.5)];  
21.     [fromView.layer setAnchorPoint:CGPointMake(1, 0.5)];  
22.       
23. //    [generalContentView setTransform:CGAffineTransformMakeTranslation(generalContentView.frame.size.width/2.0, 0)];  
24.       
25.     viewFromTransform.m34 = PERSPECTIVE;  
26.     viewToTransform.m34 = PERSPECTIVE;  
27.       
28.     toView.layer.transform = viewToTransform;  
29.       
30.   
31.     //Add the to- view  
32.     [generalContentView addSubview:toView];  
33.       
34.     [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{  
35.         [generalContentView setTransform:CGAffineTransformMakeTranslation(-generalContentView.frame.size.width/2.0, 0)];  
36.           
37.         fromView.layer.transform = viewFromTransform;  
38.         toView.layer.transform = CATransform3DIdentity;  
39.           
40.     } completion:^(BOOL finished) {  
41.           
42.         //Set the final position of every elements transformed  
43.         [generalContentView setTransform:CGAffineTransformIdentity];  
44.         fromView.layer.transform = CATransform3DIdentity;  
45.         toView.layer.transform = CATransform3DIdentity;  
46.         [fromView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];  
47.         [toView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];  
48.           
49.           
50.         if ([transitionContext transitionWasCancelled]) {  
51.             [toView removeFromSuperview];  
52.         } else {  
53.             [fromView removeFromSuperview];  
54.         }  
55.           
56.         // inform the context of completion  
57.         [transitionContext completeTransition:![transitionContext transitionWasCancelled]];  
58.           
59.     }];  
60. }  

-(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{    return 0.5f;}-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{    //Create the differents 3D animations    CATransform3D viewFromTransform;    CATransform3D viewToTransform;        UIView *generalContentView = [transitionContext containerView];    UIView *fromView = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view;    UIView *toView = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view;        viewFromTransform = CATransform3DMakeRotation(ROTATION_ANGLE, 0.0, 1.0, 0.0);    viewToTransform = CATransform3DMakeRotation(-ROTATION_ANGLE, 0.0, 1.0, 0.0);    [toView.layer setAnchorPoint:CGPointMake(0, 0.5)];    [fromView.layer setAnchorPoint:CGPointMake(1, 0.5)];    //    [generalContentView setTransform:CGAffineTransformMakeTranslation(generalContentView.frame.size.width/2.0, 0)];        viewFromTransform.m34 = PERSPECTIVE;    viewToTransform.m34 = PERSPECTIVE;        toView.layer.transform = viewToTransform;        //Add the to- view    [generalContentView addSubview:toView];        [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{        [generalContentView setTransform:CGAffineTransformMakeTranslation(-generalContentView.frame.size.width/2.0, 0)];                fromView.layer.transform = viewFromTransform;        toView.layer.transform = CATransform3DIdentity;            } completion:^(BOOL finished) {                //Set the final position of every elements transformed        [generalContentView setTransform:CGAffineTransformIdentity];        fromView.layer.transform = CATransform3DIdentity;        toView.layer.transform = CATransform3DIdentity;        [fromView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];        [toView.layer setAnchorPoint:CGPointMake(0.5f, 0.5f)];                        if ([transitionContext transitionWasCancelled]) {            [toView removeFromSuperview];        } else {            [fromView removeFromSuperview];        }                // inform the context of completion        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];            }];}

待切换的VC的动画效果配置代码：

Object-c代码  

1. -(IBAction)changeViewController:(id)sender  
2. {  
3.     ToViewController *vc =[[ToViewController alloc] init];  
4.     vc.delegate = self;  
5.     vc.transitioningDelegate = self;  
6.     [self.interactionAnimation wireToViewController:vc];  
7.     [self presentViewController:vc animated:YES completion:nil];  
8. }  
9.   
10. -(void) didClickedDismissButton:(ToViewController *)viewController  
11. {  
12.     [self dismissViewControllerAnimated:YES completion:nil];  
13. }  
14.   
15. - (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source  
16. {  
17.     return self.presentAnimation;  
18. }  
19.   
20. -(id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed  
21. {  
22.     return self.cubeAnimation;  
23. }  
24.   
25. -(id <UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator  
26. {  
27.     return self.interactionAnimation.interacting? self.interactionAnimation:nil;  
28. }  

-(IBAction)changeViewController:(id)sender{    ToViewController *vc =[[ToViewController alloc] init];    vc.delegate = self;    vc.transitioningDelegate = self;    [self.interactionAnimation wireToViewController:vc];    [self presentViewController:vc animated:YES completion:nil];}-(void) didClickedDismissButton:(ToViewController *)viewController{    [self dismissViewControllerAnimated:YES completion:nil];}- (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{    return self.presentAnimation;}-(id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed{    return self.cubeAnimation;}-(id <UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator{    return self.interactionAnimation.interacting? self.interactionAnimation:nil;}

整个示例的完整代码已提交到Github上：https://github.com/xianlinbox/iOS7_New/tree/master/iOS7_New/VCTransitions