animateWithDuration基於完全不相關的代碼行做動畫

Question

今天animateWithDuration表現得非常愚蠢，我不知道爲什麼真的如此。我檢查了所有的東西，所有的括號和一切都很完美，但它始終呈現我沒有指定爲動畫的代碼行。

好吧，所以這裏就是要點。我有一個longPressGestureRecognizer。它在一些UIImageView上，在longPress開始之後被拖動。當它在某個特殊區域結束時，我想啓動動畫，將UIImageView帶到其他位置並完成它。這裏是我的代碼：

if ([(UILongPressGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) { 
    CGPoint dropPoint = CGPointMake(self.center.x, self.center.y-5); 
    for (UIView * placeForCharacter in delegate.subviews) { 
     if ([placeForCharacter isKindOfClass:[PlaceForCharacterCircle class]]) { 
      PlaceForCharacterCircle * newPlaceForCharacter = (PlaceForCharacterCircle *) placeForCharacter; 
      if (CGRectContainsPoint(newPlaceForCharacter.dropZone, dropPoint)) { 
        UIViewAnimationOptions options = 0; 
        [UIView animateWithDuration:0.2 delay:0.0 options:0 animations:^{ 
         self.frame = CGRectMake(newPlaceForCharacter.frame.origin.x-8, newPlaceForCharacter.frame.origin.y-5, 40, 55); 
         self.alpha = 0.5; 
        } 
        completion:^(BOOL finished){ 
         NSLog(@"animation completed"); 
         self.alpha=1; 
         //code referring to the finalizing of moving, doesn't matter here 
         return; 
        }]; 
      } else { 
       if (CGRectContainsPoint(newPlaceForCharacter.dropZone, dropPoint)) { 
        //code referring to the moving to the other place in case the UIImageView was dropped on another zone that is full already, doesn't matter here 
        return; 
       } 
      } 
     } 
    } 
     //code referring to the comeback of a UIImageView in case it was dropped somewhere else, doesn't matter here 
     //These two are the lines that get executed when the animation starts 
     //THEY BEGIN 
     translatedPoint = CGPointMake(initialX, initialY); 
     [[sender view] setCenter:translatedPoint]; 
     //THEY END 
     return; 
} 

的情況是，一些奇怪的原因的代碼上面兩行得到的動畫，而不是真正的動畫，被指定。我通過在這些代碼行上添加註釋來檢查它 - 在這種情況下，動畫工作得很好。

有人可以請我清楚這一點，爲什麼會發生這種情況？這似乎是一個非常奇怪的行爲。

Answer 1

如果您將return;從完成塊（它沒有做任何事情）移動到動畫設置後，它應該工作。

[UIView animateWithDuration:0.2 delay:0.0 options:0 animations:^{ 
    self.frame = CGRectMake(newPlaceForCharacter.frame.origin.x-8, newPlaceForCharacter.frame.origin.y-5, 40, 55); 
    self.alpha = 0.5; 
} 
completion:^{ 
    NSLog(@"animation completed"); 
    self.alpha=1; 
    //code referring to the finalizing of moving, doesn't matter here 
}]; 
return;