CoreAnimation：將動畫對象轉移到下一個UIViewController

Question

我目前使用這個核心動畫; （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]; 

有了這段代碼，就有10個雪片被呈現，掉下來。

藉助此代碼以及一些自定義視圖轉換，我正在嘗試使導航操作變得流暢。問題是我無法找到正確的方法將這些（動畫）上下文轉移到下一個UIViewController，所以所有的動畫片雪花將繼續保持他們離開的位置，並且下一個UIViewController的NSTimer將激發新的動畫。

任何幫助和建議將appriciated。

Answer 1

也許你可以把你的上下文放在你這個類的私有擴展中。
我喜歡：@property (nonatomic,weak)IBOutlet UIImageView*context;

Answer 2

我懷疑你是否可以傳遞一個動畫視圖到另一個視圖控制器。我懷疑當你從它的超級視圖中刪除它時，它會終止任何動畫。

您可能會更好地編寫跟蹤在數組中動畫的視圖的代碼。當需要創建新的視圖控制器時，查詢每個圖像視圖的圖層的presentationLayer並獲取它的位置。然後從當前視圖控制器中刪除所有雪花視圖，並將整個數組以及一系列位置傳遞給新的視圖控制器。然後在新視圖控制器的viewDidLoad中，將雪花視圖數組添加到它們以前的位置，並開始動畫到它們以前的結束位置，並啓動動畫計時器以開始添加更多的雪花。

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]; 
    }]; 
} 

此代碼似乎做的工作。就目前而言，我並沒有將它用作Singleton，但是如果我將擴展這些代碼，它應該作爲一個單例來實現，只是爲了澄清。我使用的是NSDictionary而不是NSArray，它可以像現在這樣工作，再次考慮我可能會添加一些功能，因此我將其設置爲NSDictionary