沿着一系列CGPoints移动图像 [英] Moving an image along a series of CGPoints

问题描述

我将路径存储在CGPoints数组中，我想移动图像。这是我到目前为止的一般代码：

I have path stored in an array of CGPoints which I'd like to move an image along. Here's the general code I have so far:

-(void)movePic:(id)sender{
    for(int i = 0; i < self.array.count; i++){
        CGPoint location = [[self.array objectAtIndex:i] CGPointValue];
        [UIView animateWithDuration:0.1 animations:^{
            self.imageView.center = location;
        } completion:^(BOOL finished){
        }];
    }
}

问题是for循环运行得非常快，所以你只看到最后几点的动画。我不确定如何更好地设计这个。理想情况下，我可以做些什么来确保一个动画在另一个动画开始之前完成？我不应该使用for循环吗？谢谢

The problem is the for loop runs extremely fast, so you only see the animation on the last points. I'm unsure of how to better design this. Ideally, what could I do to make sure one animation finishes before the other begins? Should I not use a for loop? Thanks

推荐答案

您的代码假设UIView动画在主线程中同步运行，而不是。

Your code assumes that UIView animations run synchronously in the main thread, which they do not.

您似乎有两个选择

• 明确 CAKeyframeAnimation 沿着任意数量的样本点（在它们之间插入）动画 CALayer


• 隐式递归 UIView 沿着一系列样本点（在它们之间插入）动画 UIView 的动画

• Explicit CAKeyframeAnimation for animating a CALayer along any amount of sample points (interpolated between them)
• Implicit recursive UIView animation for animating a UIView along a series of sample points (interpolated between them)

前者会更有效率 - 我仍然认为我可以向你展示这两个选项。

The former would be much more efficient - still I thought I oould show you both options.

- (void)movePic:(id)sender
{
    //create a mutable core-graphics path
    CGMutablePathRef path = CGPathCreateMutable();
    for(int i = 0; i < self.array.count; i++)
    {
        CGPoint location = [[self.array objectAtIndex:index] CGPointValue];
        CGPathAddLineToPoint(path, nil, location.x, location.y);
    }
    //create a new keyframe animation
    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    //add our path to it
    pathAnimation.path = path;
    //be nice to the system
    CGPathRelease(path);
    //setup some more animation parameters
    pathAnimation.duration = 0.1 * self.array.count;
    //add the animation to our imageView's layer (which will start the animation)
    [self.imageView.layer addAnimation:pathAnimation forKey:@"pathAnimation"];
}

UIView动画

UIView Animation

- (void)movePicToPointAtIndex:(unsigned int)index
{
    //safeguard check...
    if ([self.array count] <= index)
        return;
    //get the next location
    CGPoint location = [[self.array objectAtIndex:index] CGPointValue];
    //animate the imageView center towards that location
    [UIView animateWithDuration:0.1 
                          delay:0.0 
                        options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionAllowUserInteraction
                     animations:^{
        self.imageView.center = location;
    } completion:^(BOOL finished){
        //we are done with that animation, now go to the next one...
        [self movePicToPointAtIndex:index+1];
    }];
}

- (void)movePic:(id)sender
{
    [self movePicToPointAtIndex:0];
}

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