ios - 是否可以连续使用 UISnapBehavior 捕捉 UIView

Question

我正在研究 CS193P，我想创建一种效果，让卡片从 0,0 一个接一个地卡入到位。我试图链接动画，但 View 一起飞行，我也在尝试使用 UIDynamicAnimator 并且发生了同样的事情。所有的 View 都在捕捉在一起。这是我必须捕捉 View 的代码。

-(void)snapCardsForNewGame
{
    for (PlayingCardView *cardView in self.cards){
        NSUInteger cardViewIndex = [self.cards indexOfObject:cardView];
        int cardColumn = (int) cardViewIndex / self.gameCardsGrid.rowCount;
        int cardRow = (int) cardViewIndex % self.gameCardsGrid.rowCount;
        UISnapBehavior *snapCard = [[UISnapBehavior alloc]initWithItem:cardView snapToPoint:[self.gameCardsGrid centerOfCellAtRow:cardRow inColumn:cardColumn]];
        snapCard.damping = 1.0;
        [self.animator addBehavior:snapCard];

    }


}


-(void)newGame
{
    NSUInteger numberOfCardsInPlay = [self.game numberOfCardsInPlay];
    for (int i=0; i<numberOfCardsInPlay; i++) {
        PlayingCardView *playingCard = [[PlayingCardView alloc]initWithFrame:CGRectMake(0, 0, 50, 75)];
        playingCard.faceUp = YES;
        [playingCard addGestureRecognizer:[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(flipCard:)]];
        [self.cards addObject:playingCard];
        //NSUInteger cardViewIndex = [self.cards indexOfObject:playingCard];
        //int cardColumn = (int) cardViewIndex / self.gameCardsGrid.rowCount;
        //int cardRow = (int) cardViewIndex % self.gameCardsGrid.rowCount;

       // playingCard.frame = [self.gameCardsGrid frameOfCellAtRow:cardRow inColumn:cardColumn];
        playingCard.center = CGPointMake(0, 0);
        [self.gameView addSubview:playingCard];
        [self snapCardsForNewGame];
    }
}

在这种情况下使用它是否有意义？我尝试了几种不同的方法来让卡片一张一张地飞起来，但没能做到。

提前致谢!

Answer 1

由于您要添加所有 UISnapBehaviors同时，动画师将它们一起运行。延迟将它们添加到动画师中，它们将自行制作动画。

-(void)snapCardsForNewGame
{
    for (PlayingCardView *cardView in self.cards){
        NSUInteger cardViewIndex = [self.cards indexOfObject:cardView];
        int cardColumn = (int) cardViewIndex / self.gameCardsGrid.rowCount;
        int cardRow = (int) cardViewIndex % self.gameCardsGrid.rowCount;
        UISnapBehavior *snapCard = [[UISnapBehavior alloc]initWithItem:cardView snapToPoint:[self.gameCardsGrid centerOfCellAtRow:cardRow inColumn:cardColumn]];
        snapCard.damping = 1.0;

        NSTimeInterval delayTime = 0.01 * cardViewIndex;
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            [self.animator addBehavior:snapCard];
        });
    }
}