Question

所以，我有一个UIImageView，它有一个动画UIImage。 UIImageView本身使用CAKeyframeAnimation和CGMutablePathRef进行动画处理，以在路径中提供一些随机性。我的问题是我需要跟踪某人何时点击动画UIIMageView。

我已经把头撞到墙上一段时间了，似乎我应该将UITouch与UIImage在屏幕上的表现层的位置进行比较，但我无法弄清楚如何获得它的坐标。

所以主要的问题是，我如何获得在屏幕上设置动画的UIIMageView的坐标，并将其与点击发生的位置进行比较？

如果我现在运行代码，则会抛出错误：

- [CALayer center]：无法识别的选择器发送到实例0xa105150

它不再崩溃，但我仍然不知道如何确定UIImageView在屏幕上移动时的位置。

我的相关代码如下。任何帮助将不胜感激。

- (void)animateCarrierFish
{
    NSInteger getWhichFish = (arc4random()%[self.fishes count]);
    NSArray *selectedFish = [NSArray arrayWithArray:[self.fishes objectAtIndex:getWhichFish]];
    UIImage *fishName = [selectedFish objectAtIndex:0];

    UIImageView *fishCarrier = [[UIImageView alloc] initWithImage:fishName];
    fishCarrier.animationImages = selectedFish;
    fishCarrier.animationDuration = 1.5;
    fishCarrier.animationRepeatCount = 0;
    fishCarrier.frame = CGRectMake(0, 0, fishName.size.width*screenScale, fishName.size.height*screenScale);

    NSInteger startPoint;
    NSInteger endPoint;
    NSInteger oppositeMod;

    NSInteger fromWhichDirection = (arc4random()%2);
    if(fromWhichDirection==1)
    {
        startPoint = rightEdge;
        endPoint = leftEdge;
        oppositeMod = -rightEdge;
        fishCarrier.transform = CGAffineTransformMakeScale(-1, 1);
    } else {
        startPoint = leftEdge;
        endPoint = rightEdge;
        oppositeMod = 0;
    }

    NSInteger aniSpeed = [self getRandomNumberBetweenMin:15 andMax:20];

    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    pathAnimation.duration = aniSpeed;
    pathAnimation.calculationMode = kCAAnimationCubic;
    pathAnimation.fillMode = kCAFillModeForwards;
    pathAnimation.removedOnCompletion = NO;

    CGMutablePathRef pointPath = CGPathCreateMutable();

    NSInteger yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor];
    CGPathMoveToPoint(pointPath, NULL, startPoint, yPoint);

    NSInteger howManyDips = [self getRandomNumberBetweenMin:2 andMax:4];

    int i=0;
    for (i = 0; i < howManyDips; i++)
    {
        yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor];
        NSInteger xMod = [self getRandomNumberBetweenMin:-25 andMax:25];

        NSInteger xPoint = (([[UIScreen mainScreen] bounds].size.height/(howManyDips+1))*(i+1)) + xMod + oppositeMod;
        if (xPoint <0)
        {
            xPoint = xPoint*-1;
        }
        CGPathAddLineToPoint(pointPath, NULL, xPoint, yPoint);
    }

    yPoint = [self getRandomNumberBetweenMin:waterLine andMax:seaFloor];
    CGPathAddLineToPoint(pointPath, NULL, endPoint, yPoint);
    pathAnimation.path = pointPath;
    CGPathRelease(pointPath);


    [fishCarrier.layer addAnimation:pathAnimation forKey:@"pathAnimation"];
    [self.view addSubview:fishCarrier];
    [fishCarrier startAnimating];

    fishCarrier.userInteractionEnabled = YES; // these two lines don't seem to do anything
    fishCarrier.multipleTouchEnabled = YES;
    fishCarrier.tag=[self.swimmers count];

    [self.swimmers addObject:fishCarrier];
}

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint touch_point = [touch locationInView:self.view];


    for (UIImageView *image in self.swimmers) {
        // HOW do I get the coordinates in the main view of this sublayer?
    }
}

Answer 1

我终于让对象报告了他们在屏幕上的位置，使用了对touchesBegan方法的以下更改：

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint startPoint = [touch locationInView:self.view];
    CGFloat x = startPoint.x;
    CGFloat y = startPoint.y;

    //create touch point
    CGPoint touchPoint = CGPointMake(x, y);

    // loop through the items we're iterested in being tapped on here
    for (UIImageView *fish in self.swimmers) {
        CGRect fishFrame = [[fish.layer presentationLayer] frame];

        if (CGRectContainsPoint(fishFrame, touchPoint)) {
            NSLog(@"You hit fish: %u",fish.tag); // do stuff here
        }
    }
}

Answer 2

为什么期望CALayer回复center消息？如果您已阅读其documentation，您会发现它没有实现名为center的方法。如果要获取图层的几何中心，请手动计算：

CGPoint center;
center.x = CGRectGetMidX(layer.bounds);
center.y = CGRectGetMidY(layer.bounds);

编辑：你似乎想要中心相对于超级（图层？视图？无论如何......）：

CGPoint center;
center.x = CGRectGetMidX(layer.frame);
center.y = CGRectGetMidY(layer.frame);

如何获取动画UIImageView的坐标

2 个答案: