CoreAnimation：将动画对象转移到下一个UIViewController

Question

我目前使用这个核心动画; （iOS 5中，ARC）

- (void)onTimer 
{ 
    // build a view from our image 
    UIImageView* flakeView = [[UIImageView alloc] initWithImage:flakeImage]; 

    // use the random() function to randomize up our flake attributes 
    int startX = round(random() % 320); 
    int endX = startX; //round(random() % 320); 
    double scale = 1/round(random() % 100) + 1.0; 
    double speed = 1/round(random() % 100) + 1.0; 

    // set the flake start position 
    flakeView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale); 
    flakeView.alpha = 0.8; 

    // put the flake in our main view 
    [self.view addSubview:flakeView]; 
    [self.view sendSubviewToBack:flakeView]; 

    [UIView beginAnimations:nil context:(__bridge void*)flakeView]; 
    // set up how fast the flake will fall 
    [UIView setAnimationDuration:10 * speed]; 

    // set the postion where flake will move to 
    flakeView.frame = CGRectMake(endX, 500.0, 25.0 * scale, 25.0 * scale); 

    // set a stop callback so we can cleanup the flake when it reaches the 
    // end of its animation 
    [UIView setAnimationDidStopSelector:@selector(onAnimationComplete:finished:context:)]; 
    [UIView setAnimationDelegate:self]; 
    [UIView commitAnimations]; 

} 
- (void)onAnimationComplete:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context { 

    UIImageView *flakeView = (__bridge UIImageView*)context; 
    [flakeView removeFromSuperview]; 
    flakeView = nil; 
} 

火;

[NSTimer scheduledTimerWithTimeInterval:(0.3) target:self selector:@selector(onTimer) userInfo:nil repeats:YES]; 

有了这段代码，就有10个雪片被呈现，掉下来。

借助此代码以及一些自定义视图转换，我正在尝试使导航操作变得流畅。问题是我无法找到正确的方法将这些（动画）上下文转移到下一个UIViewController，所以所有的动画片雪花将继续保持他们离开的位置，并且下一个UIViewController的NSTimer将激发新的动画。

任何帮助和建议将appriciated。

Answer 1

也许你可以把你的上下文放在你这个类的私有扩展中。
我喜欢：@property (nonatomic,weak)IBOutlet UIImageView*context;

Answer 2

我怀疑你是否可以传递一个动画视图到另一个视图控制器。我怀疑当你从它的超级视图中删除它时，它会终止任何动画。

您可能会更好地编写跟踪在数组中动画的视图的代码。当需要创建新的视图控制器时，查询每个图像视图的图层的presentationLayer并获取它的位置。然后从当前视图控制器中删除所有雪花视图，并将整个数组以及一系列位置传递给新的视图控制器。然后在新视图控制器的viewDidLoad中，将雪花视图数组添加到它们以前的位置，并开始动画到它们以前的结束位置，并启动动画计时器以开始添加更多的雪花。

Answer 3

.h文件中

.m文件

+ (id)sharedManager { 
    static BeanManager *sharedMyManager = nil; 
    static dispatch_once_t onceToken; 
    dispatch_once(&onceToken, ^{ 
     sharedMyManager = [[self alloc] init]; 
    }); 
    return sharedMyManager; 
} 

- (id)init { 
    if (self = [super init]) { 
     coffeebean = [UIImage imageNamed:@"coffeebean"]; 

     // assign self as navigation controllers delegate 
     AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate]; 
     [appDelegate.navigationController setDelegate:self]; 

     self.currentViewController = appDelegate.navigationController.visibleViewController; 

     beanDictionary = [[NSMutableDictionary alloc] init]; 

     NSLog(@"%@ : Allocating",[self class]); 

     [self validate]; 
    } 
    return self; 
} 

- (void)dealloc { 
    if (isDebugging) { 
     NSLog(@"%@: Deallocating", [self class]); 
    } 
} 

#pragma mark - UINavigationController 
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated 
{ 
    if (isDebugging) { 
     NSLog(@"%@: Pushing %d beans to new view",[self class], [[beanDictionary allKeys] count]); 
    } 
    for (UIImageView *animatingBeans in [beanDictionary allValues]) { 
     [viewController.view addSubview:animatingBeans]; 
     [viewController.view sendSubviewToBack:animatingBeans]; 
    } 

    self.currentViewController = viewController; 
} 

#pragma mark - Internals 
- (void)validate 
{ 
    beanTimer = [NSTimer scheduledTimerWithTimeInterval:(0.3) target:self selector:@selector(onTimerWithBlock) userInfo:nil repeats:YES]; 
} 

- (void)invalidate 
{ 
    [beanTimer invalidate]; 
} 

- (void)onTimerWithBlock 
{ 
    // build a view from our flake image 
    UIImageView* beanView = [[UIImageView alloc] initWithImage:coffeebean]; 

    // use the random() function to randomize up our flake attributes 
    int startX = round(random() % 320); 
    int endX = startX; //round(random() % 320); 
    double scale = 1/round(random() % 100) + 1.0; 
    double speed = 1/round(random() % 100) + 1.0; 

    // set the flake start position 
    beanView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale); 
    beanView.alpha = 0.8; 
    beanView.tag = contextTag; 

    [beanDictionary setObject:beanView forKey:[NSString stringWithFormat:@"%d",contextTag]]; 

    if (contextTag > 1000) { 
     contextTag = 0; 
    } 
    contextTag++; 

    // put the flake in our main view 
    [self.currentViewController.view addSubview:beanView]; 
    [self.currentViewController.view sendSubviewToBack:beanView]; 

    [UIView animateWithDuration:(speed * 10) animations:^{ 

     [beanView setFrame:CGRectMake(endX, 500.0, 25.0 * scale, 25.0 * scale)]; 

    } completion:^(BOOL finished) 
    { 
     [beanDictionary removeObjectForKey:[NSString stringWithFormat:@"%d",beanView.tag]]; 
     if (isDebugging) { 
      NSLog(@"%@: Dictionary Count %d",[self class], [[beanDictionary allKeys] count]); 
     } 
     [beanView removeFromSuperview]; 
    }]; 
} 

此代码似乎做的工作。就目前而言，我并没有将它用作Singleton，但是如果我将扩展这些代码，它应该作为一个单例来实现，只是为了澄清。我使用的是NSDictionary而不是NSArray，它可以像现在这样工作，再次考虑我可能会添加一些功能，因此我将其设置为NSDictionary