Question

我试图在我的应用程序中显示车辆在道路上的移动。为此，我保持车辆静止，并在车道上从上到下连续移动车道以产生效果。这些车道被添加为roadView的子视图，我正在尝试为roadView中的所有子视图设置动画，如下面的代码所示。

我面临的问题是，尽管我正在根据恒定速度计算持续时间，但最接近底部的车道以较快的速度移动，而开头的车道则比最开始的车道高。

-(void)animateLanes {

for (UIView *laneView in [self.roadView subviews]) {

    if (laneView.tag < 10) {
        float distance = self.view.frame.size.height - CGRectGetMaxY(laneView.frame);
        float duration = distance/10;

        [UIView animateWithDuration:duration animations:^{

            laneView.frame = CGRectMake(laneView.frame.origin.x, self.view.frame.size.height+laneView.frame.size.height, laneView.frame.size.width, laneView.frame.size.height);


        } completion:^(BOOL finished) {

            laneView.frame = CGRectMake(self.roadView.frame.size.width/2 - 10, -laneView.frame.size.height, 20, 40);
            [self nextStep:laneView];
        }];
    }
}
}

-(void) nextStep:(UIView *) laneView{

float distance = self.view.frame.size.height - CGRectGetMaxY(laneView.frame);
float duration = distance/10;

[UIView animateWithDuration:duration delay:0 options:UIViewAnimationOptionRepeat animations:^{

    laneView.frame = CGRectMake(laneView.frame.origin.x, self.view.frame.size.height+laneView.frame.size.height, laneView.frame.size.width, laneView.frame.size.height);
} completion:^(BOOL finished) {
    laneView.frame = CGRectMake(self.roadView.frame.size.width/2 - 10, -laneView.frame.size.height, 20, 40);

}];
}

Answer 1

我绝对会考虑SpriteKit这种事情。 SKScene中的更新循环将允许您确保一切运行顺利。

但是，如果您这样做，则不必进行所有这些UIView动画调用。这样做：

//calculate duration and distance first, then:
[UIView animateWithDuration:duration animations:^{    

    for (UIView *laneView in [self.roadView subviews]) {
        laneView.frame = CGRectMake(laneView.frame.origin.x, self.view.frame.size.height+laneView.frame.size.height, laneView.frame.size.width, laneView.frame.size.height);
    }


} completion:^(BOOL finished) {
    for (UIView *laneView in [self.roadView subviews]) {
        laneView.frame = CGRectMake(self.roadView.frame.size.width/2 - 10, -laneView.frame.size.height, 20, 40);
        [self nextStep:laneView];
    }
}];

虽然我根本不建议这样做。使用游戏库，即SpriteKit，因为它易于集成和简单。

Answer 2

对于这类任务，IMO，

SpriteKit 更有意义。逻辑类似，对象属于 SKScene 实例，它具有方便的更新方法，非常适合您的目标循环效果。

连续动画一组UIView子视图

2 个答案: