WWDC 2013 Session笔记 - iOS7中的ViewController切换

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//ContainerVC.m

[self addChildViewController:toVC];
[fromVC willMoveToParentViewController:nil];
[self.view addSubview:toVC.view];

__weak id weakSelf = self;
[self transitionFromViewController:fromVC
toViewController:toVC duration:0.3
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{}
completion:^(BOOL finished) {
[fromVC.view removeFromSuperView];
[fromVC removeFromParentViewController];
[toVC didMoveToParentViewController:weakSelf];
}];

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//ModalViewController.h

@class ModalViewController;
@protocol ModalViewControllerDelegate <NSObject>

-(void) modalViewControllerDidClickedDismissButton:(ModalViewController *)viewController;

@end

@interface ModalViewController : UIViewController
@property (nonatomic, weak) id<ModalViewControllerDelegate> delegate;
@end

//ModalViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
self.view.backgroundColor = [UIColor lightGrayColor];

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
[button setTitle:@"Dismiss me" forState:UIControlStateNormal];
[button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
}

-(void) buttonClicked:(id)sender
{
if (self.delegate && [self.delegate respondsToSelector:@selector(modalViewControllerDidClickedDismissButton:)]) {
[self.delegate modalViewControllerDidClickedDismissButton:self];
}
}

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//MainViewController.m

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
[button setTitle:@"Click me" forState:UIControlStateNormal];
[button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
}

-(void) buttonClicked:(id)sender
{
ModalViewController *mvc =  [[ModalViewController alloc] init];
mvc.delegate = self;
[self presentViewController:mvc animated:YES completion:nil];
}

-(void)modalViewControllerDidClickedDismissButton:(ModalViewController *)viewController
{
[self dismissViewControllerAnimated:YES completion:nil];
}

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//BouncePresentAnimation.h
@interface BouncePresentAnimation : NSObject<UIViewControllerAnimatedTransitioning>

@end

//BouncePresentAnimation.m
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 0.8f;
}

- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
// 1. Get controllers from transition context
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

// 2. Set init frame for toVC
CGRect screenBounds = [[UIScreen mainScreen] bounds];
CGRect finalFrame = [transitionContext finalFrameForViewController:toVC];
toVC.view.frame = CGRectOffset(finalFrame, 0, screenBounds.size.height);

// 3. Add toVC's view to containerView
UIView *containerView = [transitionContext containerView];
[containerView addSubview:toVC.view];

// 4. Do animate now
NSTimeInterval duration = [self transitionDuration:transitionContext];
[UIView animateWithDuration:duration
delay:0.0
usingSpringWithDamping:0.6
initialSpringVelocity:0.0
options:UIViewAnimationOptionCurveLinear
animations:^{
toVC.view.frame = finalFrame;
} completion:^(BOOL finished) {
// 5. Tell context that we completed.
[transitionContext completeTransition:YES];
}];
}

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@interface MainViewController ()<ModalViewControllerDelegate, UIViewControllerTransitioningDelegate>
@property (nonatomic, strong) BouncePresentAnimation *presentAnimation;
@end

@implementation MainViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
_presentAnimation = [BouncePresentAnimation new];
}
return self;
}

-(void) buttonClicked:(id)sender
{
//...
mvc.transitioningDelegate = self;
//...
}

- (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
return self.presentAnimation;
}

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//SwipeUpInteractiveTransition.h
@interface SwipeUpInteractiveTransition : UIPercentDrivenInteractiveTransition

@property (nonatomic, assign) BOOL interacting;

- (void)wireToViewController:(UIViewController*)viewController;

@end

//SwipeUpInteractiveTransition.m
@interface SwipeUpInteractiveTransition()
@property (nonatomic, assign) BOOL shouldComplete;
@property (nonatomic, strong) UIViewController *presentingVC;
@end

@implementation SwipeUpInteractiveTransition
-(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.y / 400.0;
//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;
}
}

@end

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//MainViewController.m
@interface MainViewController ()<ModalViewControllerDelegate,UIViewControllerTransitioningDelegate>
//...
// 1. Add dismiss animation and transition controller
@property (nonatomic, strong) NormalDismissAnimation *dismissAnimation;
@property (nonatomic, strong) SwipeUpInteractiveTransition *transitionController;
@end

@implementation MainViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
//...
_dismissAnimation = [NormalDismissAnimation new];
_transitionController = [SwipeUpInteractiveTransition new];
//...
}

-(void) buttonClicked:(id)sender
{
//...
// 2. Bind current VC to transition controller.
[self.transitionController wireToViewController:mvc];
//...
}

// 3. Implement the methods to supply proper objects.
-(id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
return self.dismissAnimation;
}

-(id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator {
return self.transitionController.interacting ? self.transitionController : nil;
}