iOS7之定制View Controller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:

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

-(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：

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

-(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：

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

-(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：

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. -(void) didClickedDismissButton:(ToViewController *)viewController
10. {
11. [self dismissViewControllerAnimated:YES completion:nil];
12. }
13. - (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
14. {
15. return self.presentAnimation;
16. }
17. -(id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
18. {
19. return self.cubeAnimation;
20. }
21. -(id <UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator
22. {
23. return self.interactionAnimation.interacting? self.interactionAnimation:nil;
24. }

-(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