Ios 飞行中的位置

我用它来制作一个物体沿着路径的动画。我想知道如何在动画过程中的任意点获取对象的位置，以检查是否与另一个对象发生碰撞。你知道怎么做吗？谢谢

- (void) animateCicleAlongPath {
    //Prepare the animation - we use keyframe animation for animations of this complexity
    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];

    pathAnimation.calculationMode = kCAAnimationCubic;
    [pathAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];

    pathAnimation.fillMode = kCAFillModeForwards;
    pathAnimation.removedOnCompletion = NO;
    pathAnimation.duration = 7.0;

    //Lets loop continuously for the demonstration
    pathAnimation.repeatCount = 1;

    //Setup the path for the animation - this is very similar as the code the draw the line
    //instead of drawing to the graphics context, instead we draw lines on a CGPathRef
    CGPoint endPoint = CGPointMake(endpointx, endpointy);
    CGMutablePathRef curvedPath = CGPathCreateMutable();

    CGPathMoveToPoint(curvedPath, NULL,startpointx,startpointy);


   // CGPathMoveToPoint(curvedPath, NULL, 10, 10);
     CGPathAddQuadCurveToPoint(curvedPath,NULL, controlpointx, controlpointy, endpointx, endpointy);




    //Now we have the path, we tell the animation we want to use this path - then we release the path
    pathAnimation.path = curvedPath;
    CGPathRelease(curvedPath);

    //We will now draw a circle at the start of the path which we will animate to follow the path
    //We use the same technique as before to draw to a bitmap context and then eventually create
    //a UIImageView which we add to our view
    UIGraphicsBeginImageContext(CGSizeMake(20,20));
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    //Set context variables
    CGContextSetLineWidth(ctx, 1.5);
    CGContextSetFillColorWithColor(ctx, [UIColor greenColor].CGColor);
    CGContextSetStrokeColorWithColor(ctx, [UIColor whiteColor].CGColor);
    //Draw a circle - and paint it with a different outline (white) and fill color (green)
    CGContextAddEllipseInRect(ctx, CGRectMake(1, 1, 18, 18));
    CGContextDrawPath(ctx, kCGPathFillStroke);
    UIImage *circle = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    UIImageView *circleView = [[UIImageView alloc] initWithImage:circle];
    circleView.frame = CGRectMake(1, 1, 20, 20);
    [throwingView addSubview:circleView];


    //Add the animation to the circleView - once you add the animation to the layer, the animation starts
    [circleView.layer addAnimation:pathAnimation forKey:@"moveTheSquare"];


}

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我相信你有两个问题：

• 检查碰撞
• 找出验证碰撞的位置

检查碰撞

CALayer

具有模型层和表示层。表示层为您提供所需的视觉信息。基本上，该层负责获取有关该层在屏幕上的位置的信息。您可以让它这样做：

circleView.layer.presentationLayer

找出验证碰撞的位置

您可以使用每1/60秒运行一次的

NSTimer

。但是，这不是一个好的解决方案，因为

NSTimer

只保证执行选择器所需的最短时间。通过这种方式，您可以在对象已合并后检查合并情况

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但是，您可以使用。这样，在屏幕上渲染层之前，您将收到一个调用。

是的，这就是我刚才想出来的。我和。。。animated.frame=[[animated.layer presentationLayer]frame]；我来看看CADDisplay链接谢谢。你也可以看看Nick关于Advanced Core动画的洛克伍德书籍。：）那本书太棒了：）。谢谢你的推荐@JackyBoy@TiagoAlmeida“.NSTimer只保证执行选择器所需的最短时间…”您能告诉我更多信息吗？提前感谢。@Unheilig当您使用NSTimer时，您说的是“X秒后执行此选择器”。您不会说“在X秒时执行此选择器”。每个线程都有一个主nsrunlop。此nsrunlop执行一组任务，您的NSTimer将插入该列表中。但是，您无法保证每个任务所需的时间，包括您正在寻找的现代Swift中的NSTimer（尽管可以保证它至少需要您定义的秒数）

thatLayer.presentation（）