问题描述
我正在尝试查找在屏幕上设置动画的 iPhone ImageView 的当前位置.
I am trying to find the current position of an iPhone ImageView that is animating across the screen.
我像这样创建和动画化 imageView
I create and animate the imageView like so
-(IBAction)button:(UIButton *)sender{
UIImageView *myImageView =[[UIImageView alloc] initWithImage:
[UIImage imageNamed:@"ball.png"]];
myImageView.frame = CGRectMake(0, self.view.frame.size.height/2, 40, 40);
[self.view addSubview:myImageView];
[myArray addObject:myImageView];
[UIView animateWithDuration:.5
delay:0
options:(UIViewAnimationOptionAllowUserInteraction) // | something here?)
animations:^{
myImageView.frame = CGRectOffset(myImageView.frame, 500, 0);
}
completion:^(BOOL finished){
[myArray removeObject:myImageView];
[myImageView removeFromSuperview];
[myImageView release];
}
];
}
然后为了检测 imageView 的当前 CGPoint 我每 60 秒调用一次这个方法
then to detect the current CGPoint of the imageView I call this method every 60th of a second
-(void)findPoint{
for (UIImageView *projectile in bullets) {
label.text = [NSString stringWithFormat:@"%f", projectile.center.x];
label2.text = [NSString stringWithFormat:@"%f", projectile.center.y];
}
}
然而,这只给了我动画结束的点,我想获得在屏幕上动画的图像的当前 CGPoint.除了 UIViewAnimationOptionAllowUserInteraction 之外,我是否需要应用其他选项来执行此操作?如果没有,我如何获取动画 imageView 的当前位置?
However this only gives me the point where the animation ends, I want to get the current CGPoint of the image that is animating across the screen. Is there an option that I need to apply other than UIViewAnimationOptionAllowUserInteraction to do this? If not, how do I get the current position of an animating imageView?
推荐答案
您可以使用presentationLayer - CALayer 的一个属性,它提供与当前正在显示的图层版本的近似值".像这样使用它:
You can use the presentationLayer - a property of the CALayer that "provides a close approximation to the version of the layer that is currently being displayed". Just use it like this:
CGRect projectileFrame = [[projectile.layer presentationLayer] frame];
这篇关于在动画期间访问 UIView 的当前位置的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!