Question

我有UIButton，我希望在一个方向上旋转180度，然后再旋转180度。我使用CABasicAnimation做了一段时间的动画，但这次我想用变换来做。这是我写的代码：

- (IBAction)blurAction:(id)sender {
    if (self.blurActive) {
        [UIView animateWithDuration:0.1 animations:^{
            self.blurView.alpha = 0;
            self.blurButton.transform = CGAffineTransformMakeRotation(M_PI);
        } completion:^(BOOL finished) {
            self.blurActive = NO;
        }];
    }
    else {
        [UIView animateWithDuration:0.1 animations:^{
            self.blurView.alpha = 1;
            self.blurButton.transform = CGAffineTransformMakeRotation(-M_PI);
        } completion:^(BOOL finished) {
            self.blurActive = YES;
        }];
    }
}

它第一次工作，但第二次按下按钮，没有任何反应。有人可以解释我在这里做错了吗？

Answer 1

实现这种效果的最简单方法就是旋转一个小于180°的微小量：

- (IBAction)toggle:(UIButton *)sender {
    [UIView animateWithDuration:0.2 animations:^{
        if (CGAffineTransformEqualToTransform(sender.transform, CGAffineTransformIdentity)) {
            sender.transform = CGAffineTransformMakeRotation(M_PI * 0.999);
        } else {
            sender.transform = CGAffineTransformIdentity;
        }
    }];
}

结果：

Answer 2

M_PI和-M_PI将具有相同的视觉效果

转回原来的位置应该是

self.blurButton.transform = CGAffineTransformMakeRotation(0);

- 编辑 -

要为逆时针旋转设置动画，您可以使用-2*M_PI

self.blurButton.transform = CGAffineTransformMakeRotation(-2*M_PI);

Answer 3

以下是@rob mayoff解决方案的 Swift3 代码。

UIView.animate(withDuration:0.1, animations: { () -> Void in
    if sender.transform == .identity {
        sender.transform = CGAffineTransform(rotationAngle: CGFloat(M_PI * 0.999))
    } else {
        sender.transform = .identity
    }
})

<强> Swift4

M_PI已弃用，已替换为Double.pi

UIView.animate(withDuration:0.1, animations: { () -> Void in
    if  sender.transform == .identity {
        sender.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi * 0.999))
    } else {
        sender.transform = .identity
    }
})

Answer 4

将UIButton旋转180º

UIButton.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi))

将UIButton旋转0º或再次返回

UIButton.transform = CGAffineTransform(rotationAngle: 0)

设置动画的示例

if cardViewModel.getBottomMenuVisibility() {
            [UIView .transition(
                with: bottomMenuView,
                duration: 0.3,
                options: .transitionCrossDissolve,
                animations: {
                    // Turn UIButton upside down
                    self.bottomMenu.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi))
            },
                completion: nil)]
    }
    else {
        [UIView .transition(
            with: bottomMenuView,
            duration: 0.3,
            options: .transitionCrossDissolve,
            animations: {
                // Turn UIButton back to normal
                self.bottomMenu.transform = CGAffineTransform(rotationAngle: 0)
        },
            completion: nil)]
    }

您可以在以下示例中查看我的代码： https://github.com/issuran/Scrum-Geek-Poker/blob/0d032a4b4edcf75cebae1524131f4fe6be3a5edf/Scrum%20Geek%20Poker/Features/CardCollection/View/MainScreenViewController.swift

Answer 5

要旋转＆＃39;视图将变换设置为常量CGAffineTransformIdentity，它是零的变换。这是使用变换的美妙之处，你不需要计算回来的方式，只需撤消你已经做过的事情。

Answer 6

您无法通过变换实际实现此目的，因为变换仅保存有关结束状态的信息。它们没有告诉我们应该使用哪个方向来制作，例如轮换。

实现180度前后旋转行为的最佳选择是使用CABasicAnimation。

以下是例子：

func rotateImage(forward: Bool) {
    let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
    rotationAnimation.fromValue = forward ? 0.0 : CGFloat.pi
    rotationAnimation.toValue = forward ? CGFloat.pi : 0.0
    rotationAnimation.fillMode = kCAFillModeForwards
    rotationAnimation.isRemovedOnCompletion = false
    rotationAnimation.duration = 0.5

    handleImageView.layer.add(rotationAnimation, forKey: "rotationAnimation")
}

Answer 7

Swift 4+

@IBAction private func maximizeButtonAction(_ sender: UIButton) {
        UIView.animate(withDuration: 0.2, animations: {
            sender.transform = sender.transform == .identity ? CGAffineTransform(rotationAngle: CGFloat(Double.pi * 0.999)) : .identity
        })
    }

将UIButton旋转180度并将其旋转回来

7 个答案: