是否可以连续使用UIViews来抓取UISnapBehavior

Question

我正在CS193P上工作，我想要创造一个效果，扑克牌从0,0，一个接一个地飞入其中。我试图连锁动画，但视图一起飞，我也尝试使用UIDynamicAnimator和同样的事情发生。所有的景色都合在一起了。下面是我必须捕捉视图的代码。

-(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有意义吗？我尝试了几个不同的东西，让牌一个一个地飞进来，但没能做到。

提前感谢！

Answer 1

因为您同时添加了所有的UISnapBehaviors，动画师将它们全部运行在一起。延迟添加到动画师，他们将是自己的动画。

-(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];
        });
    }
}