Question

我有一个按钮，想要在其中旋转图像：

self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI);

用户点击后，图片是向上箭头的向上箭头当再次单击该按钮时，我希望向下箭头再次旋转向上箭头，但它是逆时针旋转相同，但我只想让箭头反向向上箭头

旋转代码：

self.DashButton.imageView.transform = CGAffineTransformIdentity;

我试过

self.DashButton.imageView.transform = CGAffineTransformMakeRotation(-M_PI);

我想要的不是旋转整圆，只旋转180度和-180旋转，而不是360度全旋转

Answer 1

而不是-M_PI，请使用-3.14159。有点诡计，但是下面的代码节省了我的一天。

self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI);
self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI - 3.14159);

Answer 2

你需要的是一个负角度来反向旋转

CGAffineTransformMakeRotation（180 * CGFloat（M_PI / 180））

CGAffineTransformMakeRotation（-1 * CGFloat（M_PI / 180））

查看此答案以获得解释About CGAffineTransformMakeRotation rotation direction?

Answer 3

self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI);
self.DashButton.imageView.transform = CGAffineTransformMakeRotation(0);

Answer 4

@Maria工作答案的Swift 4版本

逆时针旋转180度：

let transform = CGAffineTransform.identity

UIView.animate(withDuration: 0.3, animations: {
      // to rotate counterclockwise set both of these in this exact order
      self.button.transform = transform.rotated(by: 180 * CGFloat(Double.pi))
      self.button.transform = transform.rotated(by: -1 * CGFloat(Double.pi))
}

顺时针旋转180度：

UIView.animate(withDuration: 0.3, animations: { 
      self.button.transform = CGAffineTransform.identity
}

Answer 5

试试这个

arrowLeft.transform = CGAffineTransformMakeRotation(180 *M_PI / 180.0);

arrowLeft.transform = CGAffineTransformMakeRotation(0*M_PI/180);

Answer 6

怎么样？

self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI);
self.DashButton.imageView.transform = CGAffineTransformMakeRotation(M_PI * 2);

它适用于我的代码：）

Answer 7

也可以使用

imageView.image = UIImage(cgImage: imageView.image!.cgImage! , scale: 1.0, orientation: .down)

Answer 8

斯威夫特3：

使用CABasicAnimation

var rotationAnimation = CABasicAnimation()
rotationAnimation = CABasicAnimation.init(keyPath: "transform.rotation.z")
rotationAnimation.toValue = NSNumber(value: (Double.pi))
rotationAnimation.duration = 1.0
rotationAnimation.isCumulative = true
rotationAnimation.repeatCount = 100.0
view.layer.add(rotationAnimation, forKey: "rotationAnimation")

这是UIView的extension函数，用于处理start＆amp;停止旋转操作：

extension UIView {

    func startRotation() {
        let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.fromValue = 0
        rotation.toValue = NSNumber(value: Double.pi)
        rotation.duration = 1.0
        rotation.isCumulative = true
        rotation.repeatCount = FLT_MAX
        self.layer.add(rotation, forKey: "rotationAnimation")
    }

    func stopRotation() {
        self.layer.removeAnimation(forKey: "rotationAnimation")
    }
}

现在使用UIView.animation闭包：

UIView.animate(withDuration: 0.5, animations: { 
      button.transform = CGAffineTransform(rotationAngle: (CGFloat(Double.pi))) 
}) { (isAnimationComplete) in
    // Animation completed 
}

旋转180度为UIImageView，并以相同的路线向后旋转

8 个答案: