如何獲取動畫UIImageView的座標

Question

因此，我有一個UIImageView，它具有動畫UIImage。 UIImageView本身使用CAKeyframeAnimation和CGMutablePathRef來動畫，以在路徑中提供一些隨機性。我的問題是我需要跟蹤何時點擊動畫的UIIMageView。

我已經把頭撞在牆上了一會兒，看起來我應該將UITouch與UIImage的表現層在屏幕上的位置進行比較，但我無法弄清楚如何獲取它的座標。

所以主要的問題是，我如何獲得UIIMageView的座標，並在屏幕上進行動畫並將其與龍頭的出現位置進行比較？

如果我運行的代碼是正確的，現在，它會拋出一個錯誤：

- [CALayer的中心]：無法識別的選擇發送到實例0xa105150

它不再崩潰，但我仍然在對於如何確定UIImageView在屏幕上移動時的位置有所損失。

我的相關代碼如下。任何幫助將不勝感激。

- (void)animateCarrierFish 
{ 
    NSInteger getWhichFish = (arc4random()%[self.fishes count]); 
    NSArray *selectedFish = [NSArray arrayWithArray:[self.fishes objectAtIndex:getWhichFish]]; 
    UIImage *fishName = [selectedFish objectAtIndex:0]; 

    UIImageView *fishCarrier = [[UIImageView alloc] initWithImage:fishName]; 
    fishCarrier.animationImages = selectedFish; 
    fishCarrier.animationDuration = 1.5; 
    fishCarrier.animationRepeatCount = 0; 
    fishCarrier.frame = CGRectMake(0, 0, fishName.size.width*screenScale, fishName.size.height*screenScale); 

    NSInteger startPoint; 
    NSInteger endPoint; 
    NSInteger oppositeMod; 

    NSInteger fromWhichDirection = (arc4random()%2); 
    if(fromWhichDirection==1) 
    { 
     startPoint = rightEdge; 
     endPoint = leftEdge; 
     oppositeMod = -rightEdge; 
     fishCarrier.transform = CGAffineTransformMakeScale(-1, 1); 
    } else { 
     startPoint = leftEdge; 
     endPoint = rightEdge; 
     oppositeMod = 0; 
    } 

    NSInteger aniSpeed = [self getRandomNumberBetweenMin:15 andMax:20]; 

    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"]; 
    pathAnimation.duration = aniSpeed; 
    pathAnimation.calculationMode = kCAAnimationCubic; 
    pathAnimation.fillMode = kCAFillModeForwards; 
    pathAnimation.removedOnCompletion = NO; 

    CGMutablePathRef pointPath = CGPathCreateMutable(); 

    NSInteger yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor]; 
    CGPathMoveToPoint(pointPath, NULL, startPoint, yPoint); 

    NSInteger howManyDips = [self getRandomNumberBetweenMin:2 andMax:4]; 

    int i=0; 
    for (i = 0; i < howManyDips; i++) 
    { 
     yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor]; 
     NSInteger xMod = [self getRandomNumberBetweenMin:-25 andMax:25]; 

     NSInteger xPoint = (([[UIScreen mainScreen] bounds].size.height/(howManyDips+1))*(i+1)) + xMod + oppositeMod; 
     if (xPoint <0) 
     { 
      xPoint = xPoint*-1; 
     } 
     CGPathAddLineToPoint(pointPath, NULL, xPoint, yPoint); 
    } 

    yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor]; 
    CGPathAddLineToPoint(pointPath, NULL, endPoint, yPoint); 
    pathAnimation.path = pointPath; 
    CGPathRelease(pointPath); 


    [fishCarrier.layer addAnimation:pathAnimation forKey:@"pathAnimation"]; 
    [self.view addSubview:fishCarrier]; 
    [fishCarrier startAnimating]; 

    fishCarrier.userInteractionEnabled = YES; // these two lines don't seem to do anything 
    fishCarrier.multipleTouchEnabled = YES; 
    fishCarrier.tag=[self.swimmers count]; 

    [self.swimmers addObject:fishCarrier]; 
} 

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    [super touchesBegan:touches withEvent:event]; 

    UITouch *touch = [touches anyObject]; 
    CGPoint touch_point = [touch locationInView:self.view]; 


    for (UIImageView *image in self.swimmers) { 
     // HOW do I get the coordinates in the main view of this sublayer? 
    } 
} 

Answer 1

我能夠最終得到的對象報告，他們使用瞭如下修改我的touchesBegan方法是在屏幕上：

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    [super touchesBegan:touches withEvent:event]; 

    UITouch *touch = [touches anyObject]; 
    CGPoint startPoint = [touch locationInView:self.view]; 
    CGFloat x = startPoint.x; 
    CGFloat y = startPoint.y; 

    //create touch point 
    CGPoint touchPoint = CGPointMake(x, y); 

    // loop through the items we're iterested in being tapped on here 
    for (UIImageView *fish in self.swimmers) { 
     CGRect fishFrame = [[fish.layer presentationLayer] frame]; 

     if (CGRectContainsPoint(fishFrame, touchPoint)) { 
      NSLog(@"You hit fish: %u",fish.tag); // do stuff here 
     } 
    } 
} 

Answer 2

你爲什麼想到CALayer向center消息作出響應？如果您已閱讀其documentation，則會發現它沒有實施名爲center的方法。如果你想獲得該層的幾何中心，手動計算的話：

CGPoint center; 
center.x = CGRectGetMidX(layer.bounds); 
center.y = CGRectGetMidY(layer.bounds); 

編輯：看來你要相對於超級中鋒（層查看什麼...？）：

CGPoint center; 
center.x = CGRectGetMidX(layer.frame); 
center.y = CGRectGetMidY(layer.frame);