移动UIImageView [英] Move a UIImageView

问题描述

沿着点阵列移动图片的最佳方法是什么？

What is the best way to move an image along an array of dots?

推荐答案

我推荐的方法是UIImage在UIImageView和使用CAKeyframeAnimation来动画你的UIImageView的图层沿着一个路径通过你的三个点：

My recommended approach would be to wrap the UIImage in a UIImageView and use a CAKeyframeAnimation to animate your UIImageView's layer along a path that passes through your three points:

UIImage *image = [UIImage imageNamed:@"image.png"];
imageView = [[UIImageView alloc] initWithImage:image];
[mainView addSubview:imageView];
// Remember to remove the image view and release it when done with it

CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.duration = 1.0f;
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;

CGMutablePathRef pointPath = CGPathCreateMutable();
CGPathMoveToPoint(pointPath, NULL, viewOrigin.x, viewOrigin.y);
CGPathAddLineToPoint(pointPath, NULL, point1.x, point1.y);
CGPathAddLineToPoint(pointPath, NULL, point2.x, point2.y);
CGPathAddLineToPoint(pointPath, NULL, point3.x, point3.y);
pathAnimation.path = pointPath;
CGPathRelease(pointPath);

[imageView.layer addAnimation:pathAnimation forKey:@"pathAnimation"];

请注意，默认情况下，图层的位置是图层的中心。如果要将图层相对于另一个参考点移动，您可以将图层的anchorPoint属性设置为其左上角（在iPhone上）（0.0，0.0）或（0.0，1.0）左边。

Note that by default, the position of a layer is at the layer's center. If you'd like to move the layer relative to another reference point, you can set the layer's anchorPoint property to something like (0.0, 0.0) for its upper-left corner (on the iPhone) or (0.0, 1.0) for its lower left.

此外，这不会改变UIImageView的框架，当它完成后，所以如果你参考那个框架以后，你可能需要采取或者为动画结束添加一个委托方法回调以将其设置为正确的值。

Also, this won't change the frame of the UIImageView when it's done, so if you refer to that frame later on, you may need to either take that into account or add a delegate method callback for the end of your animation to set it to the proper value.

您还可以使图像沿曲线移动，而不是直线

You can also make your image move along curves, instead of straight lines, by replacing the calls to CGPathAddLineToPoint() with CGPathAddCurveToPoint().

编辑（5/14/2009）：我添加了缺少的pathAnimation.path = pointPath行，并且将错误的引用改为curvedPath to pointPath。

EDIT (5/14/2009): I added the missing pathAnimation.path = pointPath line and changed a mistyped reference to curvedPath to pointPath.

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