ios - 在 iOS 中为 uibutton 将 3 行动画化为箭头

Question

有谁知道如何通过将 CGAfflineRotation 应用到 3 个 View 来将 3 条平行线动画化为右箭头，就像在导航菜单栏中发生的那样，以打开侧边菜单。

我真的需要这些方面的帮助，这样至少我可以有一个开始的想法。

这是尝试绘制它的样子:-

_______                  
_______                        \
_______         to   ___________\
                                /
                               /

任何想法或建议都会有所帮助。

Answer 1

如您所说，您应该使用CGAffineRotation。我给出了你想要的简单示例，所有内容都应该打包到适当的方法中， View 应该包含一些基本的 autolayouts/layoutFrames 等。我只是发布旋转的可能解决方案，快速写在viewDidAppear中，应该改变什么。

另一种选择是使用例如 firstView.layer.anchorPoint 并将其设置到适当的位置。

#define degreesToRadians(x) (M_PI * x / 180.0)

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];

    // let's create these 3 views as a lines
    UIView *firstView = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 50, 1)];
    [firstView setBackgroundColor:[UIColor blackColor]];
    [self.view addSubview:firstView];
    UIView *secondView = [[UIView alloc] initWithFrame:CGRectMake(50, 53, 50, 1)];
    [secondView setBackgroundColor:[UIColor blackColor]];
    [self.view addSubview:secondView];
    UIView *thirdView = [[UIView alloc] initWithFrame:CGRectMake(50, 56, 50, 1)];
    [thirdView setBackgroundColor:[UIColor blackColor]];
    [self.view addSubview:thirdView];

    // now we can perform rotation, mind the degree and offsets in transform.
    [UIView animateWithDuration:1 animations:^{
        CGAffineTransform transform = CGAffineTransformMakeTranslation(24, 1);
        transform = CGAffineTransformRotate(transform, degreesToRadians(45));
        transform = CGAffineTransformTranslate(transform, -24, 1);
        firstView.transform = transform;

        transform = CGAffineTransformIdentity;
        transform = CGAffineTransformMakeTranslation(24, -1);
        transform = CGAffineTransformRotate(transform, degreesToRadians(-45));
        transform = CGAffineTransformTranslate(transform, -24, -1);
        thirdView.transform = transform;
    } completion:^(BOOL finished) {}];
}