我试图旋转一个UIImageView 360度,并在网上看了几个教程。我不能让它们都工作,UIView要么停止,要么跳转到一个新位置。

我怎样才能做到这一点呢?

我最近尝试的是:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

但如果我使用2*pi,它根本不会移动(因为它是相同的位置)。如果我尝试只做(180度),它可以工作,但如果我再次调用这个方法,它会向后旋转。

编辑:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     [UIView setAnimationRepeatCount:HUGE_VALF];
                     [UIView setAnimationBeginsFromCurrentState:YES];
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

也不管用。它会转到180度,暂停一秒钟,然后在重新开始之前重置回0度。


当前回答

import UIKit

class RotatingImageView: UIImageView, CAAnimationDelegate {
    
    private let rotationAnimationKey = "rotationAnimationKey"

    private var shouldStopRotating = false
    
    func startRotating(witFullRotationDuration duration: Double = 0.5, halfRotation: Bool = true) {
        
        shouldStopRotating = false
        if layer.animation(forKey: rotationAnimationKey) == nil {
        
            let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation")
            rotationAnimation.fromValue = 0.0
            rotationAnimation.toValue = halfRotation ? Float.pi : Float.pi * 2
            rotationAnimation.duration = duration
            rotationAnimation.repeatCount = 1
            rotationAnimation.delegate = self
            layer.add(rotationAnimation, forKey: rotationAnimationKey)
        
        }
        
    }

    func stopRotating(immediately: Bool = false) {
        if immediately {
            if layer.animation(forKey: rotationAnimationKey) != nil {
                layer.removeAnimation(forKey: rotationAnimationKey)
            }
        } else {
            shouldStopRotating = true
        }
    }
    
    func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
    
        if !shouldStopRotating {
            startRotating(witFullRotationDuration: anim.duration)
        } else {
            if layer.animation(forKey: rotationAnimationKey) != nil {
                layer.removeAnimation(forKey: rotationAnimationKey)
            }
        }
        
    }
    
}

其他回答

Swift 3:

 var rotationAnimation = CABasicAnimation()
     rotationAnimation = CABasicAnimation.init(keyPath: "transform.rotation.z")
     rotationAnimation.toValue = NSNumber(value: (M_PI * 2.0))
     rotationAnimation.duration = 2.0
     rotationAnimation.isCumulative = true
     rotationAnimation.repeatCount = 10.0
     view.layer.add(rotationAnimation, forKey: "rotationAnimation")

这对我很管用:

[UIView animateWithDuration:1.0
                animations:^
{
    self.imageView.transform = CGAffineTransformMakeRotation(M_PI);
    self.imageView.transform = CGAffineTransformMakeRotation(0);
}];

@ram的回答很有帮助。以下是Swift版本的答案。

斯威夫特2

private func rotateImageView() {

    UIView.animateWithDuration(1, delay: 0, options: UIViewAnimationOptions.CurveLinear, animations: { () -> Void in
        self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, CGFloat(M_PI_2))
        }) { (finished) -> Void in
            if finished {
                self.rotateImageView()
            }
    }
}

斯威夫特3、4、5所示

private func rotateImageView() {

    UIView.animate(withDuration: 1, delay: 0, options: UIView.AnimationOptions.curveLinear, animations: { () -> Void in
        self.imageView.transform = self.imageView.transform.rotated(by: .pi / 2)
    }) { (finished) -> Void in
        if finished {
            self.rotateImageView()
        }
    }
}

你也可以用UIView和block做同样类型的动画。下面是一个类扩展方法,它可以以任何角度旋转视图。

- (void)rotationWithDuration:(NSTimeInterval)duration angle:(CGFloat)angle options:(UIViewAnimationOptions)options
{
    // Repeat a quarter rotation as many times as needed to complete the full rotation
    CGFloat sign = angle > 0 ? 1 : -1;
    __block NSUInteger numberRepeats = floorf(fabsf(angle) / M_PI_2);
    CGFloat quarterDuration = duration * M_PI_2 / fabs(angle);

    CGFloat lastRotation = angle - sign * numberRepeats * M_PI_2;
    CGFloat lastDuration = duration - quarterDuration * numberRepeats;

    __block UIViewAnimationOptions startOptions = UIViewAnimationOptionBeginFromCurrentState;
    UIViewAnimationOptions endOptions = UIViewAnimationOptionBeginFromCurrentState;

    if (options & UIViewAnimationOptionCurveEaseIn || options == UIViewAnimationOptionCurveEaseInOut) {
        startOptions |= UIViewAnimationOptionCurveEaseIn;
    } else {
        startOptions |= UIViewAnimationOptionCurveLinear;
    }

    if (options & UIViewAnimationOptionCurveEaseOut || options == UIViewAnimationOptionCurveEaseInOut) {
        endOptions |= UIViewAnimationOptionCurveEaseOut;
    } else {
        endOptions |= UIViewAnimationOptionCurveLinear;
    }

    void (^lastRotationBlock)(void) = ^ {
        [UIView animateWithDuration:lastDuration 
                              delay:0 
                            options:endOptions 
                         animations:^{
                             self.transform = CGAffineTransformRotate(self.transform, lastRotation);
                         } 
                         completion:^(BOOL finished) {
                             NSLog(@"Animation completed");   
                         }
         ];
    };

    if (numberRepeats) {
        __block void (^quarterSpinningBlock)(void) = ^{ 
            [UIView animateWithDuration:quarterDuration 
                                  delay:0 
                                options:startOptions 
                             animations:^{
                                 self.transform = CGAffineTransformRotate(self.transform, M_PI_2);
                                 numberRepeats--; 
                             } 
                             completion:^(BOOL finished) {
                                 if (numberRepeats > 0) {
                                     startOptions = UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear;
                                     quarterSpinningBlock();
                                 } else {
                                     lastRotationBlock();
                                 }NSLog(@"Animation completed");   
                             }
             ];

        };

        quarterSpinningBlock();
    } else {
        lastRotationBlock();
    }
}

Swift3版本:

extension UIView {

    func startRotate() {
        let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.fromValue = 0
        rotation.toValue = NSNumber(value: M_PI * 2)
        rotation.duration = 2
        rotation.isCumulative = true
        rotation.repeatCount = FLT_MAX
        self.layer.add(rotation, forKey: "rotationAnimation")
    }

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

记住在viewWillAppear中调用startRotate,而不是在viewDidLoad中。