前一篇总结了Core Animation的一些基础知识，这一篇主要是Core Animation 的一些应用，涉及到CAShapeLayer、CAReplicatorLayer等图层的知识。

先看效果图：

1、切换图片：

2、彩票转盘

3、图片折叠

4、进度条旋转

5、粒子效果

一、切换图片

看起来很复杂的动画，通过少量的计算和编码就可以简单的实现。要做到这一步，必须是需要研究iOS开发中的Core Animation和Core Graphics框架的。日常工作中，对于很多东西不求甚解，只是拿过来用，甚至都不研究、封装一下别人代码，这种做法是很不好的。我喜欢自己造轮子，轮子造多了，开发经验与思维也就提升上去了。

这个动画实现是比较简单的，利用了CABasicAnimation、CAKeyframeAnimation和CAAnimationGroup。看似是两张图片各自有着自己不同的动画，实际不过是一个动画方法，其平移方向与旋转角度的不同。

我是用了CABasicAnimation设置了view的zPosition值，CAKeyframeAnimation对象设计了图片的位移与旋转动画，然后将之放到CAAnimationGroup对象里面，开始动画。

这里有一个注意点，那就是Core Animation设置的动画位移、旋转、缩放都只是一个假象，实际上的view该怎么还是怎么样，并未真正有过变化。所以，在动画结束后，想要正确的效果，那么需要设置view的zPosition值，这个值越大，view越在前面（z轴方向上的“前面”）。

代码：

#import "ViewController.h" @interface ViewController () @property (nonatomic, strong) NSMutableArray *images; @property (nonatomic, assign) int currentIndex; @property (weak, nonatomic) IBOutlet UIImageView *currentImageView; @property (weak, nonatomic) IBOutlet UIImageView *behindImageView; @end @implementation ViewController - (NSMutableArray *)images { if (_images == nil) { _images = [NSMutableArray array]; for (int i = 1; i <= 7; i++) { UIImage *image = [UIImage imageNamed: [NSString stringWithFormat:@"%d",i]]; [_images addObject:image]; } } return _images; } - (void)viewDidLoad { [super viewDidLoad]; self.currentIndex = 0; self.currentImageView.image = self.images[_currentIndex]; } - (void)addAnimateWithPoint:(CGPoint )point angle:(CGFloat)angle fromZ:(CGFloat)fromZ toZ:(CGFloat)toZ view:(UIView *)view { CABasicAnimation *zPosition = [[CABasicAnimation alloc] init]; zPosition.keyPath = @"zPosition"; zPosition.fromValue = @(fromZ); zPosition.toValue = @(toZ); zPosition.duration = 1.2; CAKeyframeAnimation *rotation = [[CAKeyframeAnimation alloc] init]; rotation.keyPath = @"transform.rotation"; rotation.values = @[@(0), @(angle), @(0)]; rotation.duration = 2; rotation.timingFunctions = @[ [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut], [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]]; CAKeyframeAnimation *position = [[CAKeyframeAnimation alloc] init]; position.keyPath = @"position"; // CGPointMake(110, -20) position.values = @[ [NSValue valueWithCGPoint:CGPointZero], [NSValue valueWithCGPoint:point], [NSValue valueWithCGPoint:CGPointZero] ]; position.timingFunctions = @[ [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut], [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut] ]; position.additive = YES; position.duration = 1.2; CAAnimationGroup *animateGroup = [[CAAnimationGroup alloc] init]; animateGroup.animations = @[zPosition, rotation, position]; // animateGroup.beginTime = 0.5; animateGroup.delegate = self; animateGroup.duration = 1.2; [animateGroup setValue:view forKey:@"view"]; [view.layer addAnimation:animateGroup forKey:nil]; view.layer.zPosition = toZ; } - (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag { CAAnimationGroup *group = [anim valueForKey:@"view"]; if (group != nil) { self.currentImageView.image = self.images[_currentIndex]; self.currentImageView.layer.zPosition = 1; self.behindImageView.image = nil; self.behindImageView.layer.zPosition = -1; } } - (IBAction)previous:(id)sender { self.currentIndex = (self.currentIndex + 1) % self.images.count; self.behindImageView.image = self.images[_currentIndex]; [self addAnimateWithPoint:CGPointMake(-90, 20) angle:0.15 fromZ:-1 toZ:1 view:self.behindImageView]; [self addAnimateWithPoint:CGPointMake(90, -20) angle:-0.15 fromZ:1 toZ:-1 view:self.currentImageView]; } - (IBAction)next:(id)sender { self.currentIndex = (self.currentIndex + 6) % self.images.count; self.behindImageView.image = self.images[_currentIndex]; [self addAnimateWithPoint:CGPointMake(-90, 20) angle:-0.15 fromZ:-1 toZ:1 view:self.behindImageView]; [self addAnimateWithPoint:CGPointMake(90, -20) angle:0.15 fromZ:1 toZ:-1 view:self.currentImageView]; } @end

二、彩票转盘

这个动画的实现主要难点在于Button的摆放，只要摆放好button，其他就是简单的添加动画的一个过程。

12个星座，那么需要12个button。在摆放它们的时候，我是将一个个button的anchorPoint设置为(0.5, 1)，将button的position设置为中心圆的圆心，然后设置transform来旋转它们，是的达到围绕一个圆摆放的目的。

需要知道的是，一般来说，控件的anchorPoint就是控件的中心点，所以在我们做旋转、平移等操作的时候，也就是在围绕中心点的一系列操作。但是，很多时候，只是围绕中心点来设置动画的话，会很复杂，CALayer提供了一个anchorPoint属性，可以让我们自由的改变其数值，从而实现比较复杂的动画。

还有就是button的点击事件，事实上由于一个扇形区域是上边大，下边小，要是不做相应的限制，当用户点击下面的区域时，很可能不是选中当前的button，因此要做一定的限制。这里我是自定义了一个button，在里面重写了hitTest: WwthEvent: 方法，这个方法可以设置你所要监听事件的区域范围。

代码：

#import "ZYWheelView.h" #define ZYImageW 40 #define ZYImageH 46 @interface ZYButton : UIButton @end @implementation ZYButton /** * 重写此方法，截取button的点击 * */ - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event { CGFloat btnW = self.bounds.size.width; CGFloat btnH = self.bounds.size.height; CGFloat x = 0; CGFloat y = btnH / 2; CGFloat w = btnW; CGFloat h = y; CGRect rect = CGRectMake(x, y, w, h); if (CGRectContainsPoint(rect, point)) { return nil; }else{ return [super hitTest:point withEvent:event]; } } - (CGRect)imageRectForContentRect:(CGRect)contentRect { CGFloat imageX = (contentRect.size.width - ZYImageW ) * 0.5; CGFloat imageY = 18; return CGRectMake(imageX, imageY, ZYImageW, ZYImageH); } - (void)setHighlighted:(BOOL)highlighted { } @end @interface ZYWheelView () @property (weak, nonatomic) IBOutlet UIImageView *wheelView; @property (nonatomic, weak) UIButton *lastSelectedBtn; @property (nonatomic, strong) CADisplayLink *timer; @end @implementation ZYWheelView + (instancetype)wheelView { return [[[NSBundle mainBundle] loadNibNamed:@"ZYWheelView" owner:nil options:nil] lastObject]; } - (void)awakeFromNib { self.wheelView.userInteractionEnabled = YES; CGFloat angle = 2 * M_PI / 12.0; UIImage *normalImage = [UIImage imageNamed:@"LuckyAstrology"]; UIImage *selectedImage = [UIImage imageNamed:@"LuckyAstrologyPressed"]; for (int bi = 0; bi < 12; bi++) { ZYButton *btn = [[ZYButton alloc] init]; [btn setBackgroundImage:[UIImage imageNamed:@"LuckyRototeSelected"] forState:UIControlStateSelected]; // 切割图片,将切割好的图片设置到按钮上 // CGImage中rect是当做像素来使用 // UIKit 中是点坐标系 // 坐标系的特点:如果在非retain屏上 1个点等于1个像素 // 在retain屏上1个点等于2个像素 CGFloat imageH = ZYImageH * [UIScreen mainScreen].scale; CGFloat imageW = ZYImageW * [UIScreen mainScreen].scale; CGFloat imageY = 0; CGFloat imageX = bi * imageW; CGRect rect = CGRectMake(imageX, imageY, imageW, imageH); CGImageRef normalRef = CGImageCreateWithImageInRect(normalImage.CGImage, rect); CGImageRef selectedRef = CGImageCreateWithImageInRect(selectedImage.CGImage, rect); [btn setImage:[UIImage imageWithCGImage:normalRef] forState:UIControlStateNormal]; [btn setImage:[UIImage imageWithCGImage:selectedRef] forState:UIControlStateSelected]; btn.bounds = CGRectMake(0, 0, 58, 143); btn.layer.anchorPoint = CGPointMake(0.5, 1); btn.layer.position = CGPointMake(self.frame.size.width * 0.5, self.frame.size.height * 0.5); btn.transform = CGAffineTransformMakeRotation(angle * bi); [btn addTarget:self action:@selector(clickBtn:) forControlEvents:UIControlEventTouchUpInside]; [self.wheelView addSubview:btn]; } [self startRotating]; } - (void)startRotating { if (self.timer) return; self.timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(updateTimer)]; [self.timer addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes]; } - (void)stopRotating { [self.timer invalidate]; self.timer = nil; } - (void)clickBtn:(UIButton *)btn { self.lastSelectedBtn.selected = NO; btn.selected = YES; self.lastSelectedBtn = btn; } - (IBAction)clickCenterBtn:(id)sender { self.userInteractionEnabled = NO; [self stopRotating]; CABasicAnimation *basicAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"]; basicAnimation.toValue = @(M_PI * 2 * 5); basicAnimation.duration = 2; basicAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; // basicAnimation.removedOnCompletion = NO; // basicAnimation.fillMode = kCAFillModeForwards; basicAnimation.delegate = self; [self.wheelView.layer addAnimation:basicAnimation forKey:nil]; } - (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag { self.userInteractionEnabled = YES; // 根据选中的按钮获取旋转的度数, // 通过transform获取角度 CGFloat angle = atan2(self.lastSelectedBtn.transform.b, self.lastSelectedBtn.transform.a); // 从实际上旋转转盘 self.wheelView.transform = CGAffineTransformMakeRotation(-angle); dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ [self startRotating]; }); } - (void)updateTimer { self.wheelView.transform = CGAffineTransformRotate(self.wheelView.transform, M_PI / 200); } - (void)dealloc { [self stopRotating]; } @end

3、图片折叠

这个效果看起来很炫酷，但实际做起来是比较简单的。需要三个View，两个UIImageView，一个接受拖拽action的View。CALayer里面有个contentRect属性，它可以设置layer里面的显示内容，利用这个属性，我们可以做在下载图片时，下载一点展示一点的效果。 在这里，我用这个属性来这是两张UIImageView各自展示一半的图片，然后将这两张ImageView拼接在一起，显示完整的图片。

在一个覆盖这张完整图片的View上添加拖拽手势，以实现动画过程。

这里有一个新的图层需要学习下，CAGradientLayer，它是用来做颜色渐变的，用法与CALayer的用法相似：

属性代码：

CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = self.bottomView.bounds; gradientLayer.opacity = 0; gradientLayer.colors = @[(id)[UIColor clearColor].CGColor, (id)[UIColor blackColor].CGColor]; self.gradientLayer = gradientLayer; [self.bottomView.layer addSublayer:gradientLayer]; // 设置渐变颜色 // gradientL.colors = @[(id)[UIColor redColor].CGColor,(id)[UIColor greenColor].CGColor,(id)[UIColor yellowColor].CGColor]; // 设置渐变定位点 // gradientL.locations = @[@0.1,@0.4,@0.5]; // 设置渐变开始点，取值0~1 // gradientL.startPoint = CGPointMake(0, 1);

设置好之后，在pan手势的方法里面不断改变gradientLayer的opacity即可达到想要的效果。

CATransform3D有个m34属性，可以设置透视度，一般将这个值设置为- 1 / 500.0，特定需求可以微调这个值。

代码：

#import "ViewController.h" @interface ViewController () @property (weak, nonatomic) IBOutlet UIImageView *topView; @property (weak, nonatomic) IBOutlet UIImageView *bottomView; @property (weak, nonatomic) IBOutlet UIView *containView; @property (nonatomic, weak) CAGradientLayer *gradientLayer; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. [self setupOtherView]; //设置渐变的阴影 [self setupShadow]; } - (void)setupOtherView { //设置contentsRect用来表示图片显示的大小，可以做边下载边显示的UI效果,取值是(0--1) self.topView.layer.contentsRect = CGRectMake(0, 0, 1, 0.5); self.topView.layer.anchorPoint = CGPointMake(0.5, 1); self.bottomView.layer.contentsRect = CGRectMake(0, 0.5, 1, 0.5); self.bottomView.layer.anchorPoint = CGPointMake(0.5, 0); UIPanGestureRecognizer *gesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)]; [self.containView addGestureRecognizer:gesture]; } - (void)setupShadow { CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = self.bottomView.bounds; gradientLayer.opacity = 0; gradientLayer.colors = @[(id)[UIColor clearColor].CGColor, (id)[UIColor blackColor].CGColor]; self.gradientLayer = gradientLayer; [self.bottomView.layer addSublayer:gradientLayer]; // 设置渐变颜色 // gradientL.colors = @[(id)[UIColor redColor].CGColor,(id)[UIColor greenColor].CGColor,(id)[UIColor yellowColor].CGColor]; // 设置渐变定位点 // gradientL.locations = @[@0.1,@0.4,@0.5]; // 设置渐变开始点，取值0~1 // gradientL.startPoint = CGPointMake(0, 1); } - (void)pan:(UIPanGestureRecognizer *)recognizer { CGFloat y = [recognizer translationInView:self.containView].y; if (y >= 300) y = 300; if (y <= -300) y = -300; // 旋转角度,往下逆时针旋转 CGFloat angle = -y / 320.0 * M_PI; self.topView.layer.transform = CATransform3DIdentity; CATransform3D transfrom = CATransform3DIdentity; transfrom.m34 = -1 / 500.0; self.topView.layer.transform = CATransform3DRotate(transfrom, angle, 1, 0, 0); self.gradientLayer.opacity = y / 300.0; if (recognizer.state == UIGestureRecognizerStateEnded) { // 弹簧效果的动画 // SpringWithDamping:弹性系数,越小，弹簧效果越明显 [UIView animateWithDuration:0.5 delay:0 usingSpringWithDamping:0.3 initialSpringVelocity:11 options:UIViewAnimationOptionCurveEaseInOut animations:^{ self.topView.layer.transform = CATransform3DIdentity; self.gradientLayer.opacity = 0; } completion:nil]; } } @end

4、旋转进度条

圆圈旋转一般都是放在HUD上吧。记得以前我也做过一个类似的功能，那时候还没现在这样的知识储备，只能是用CAKeyframeAnimation做，让美工做出了一根顶部是一个小白点，除此之外，很长的那部分是为clearColor的小矩形，然后我设置它的anchorPoint，给 CAKeyframeAnimation添加一个圆形的path，然后围绕这个path旋转，做是勉强做出来，但是很不好看吧。

现在可以有更好的选择了，CAReplicatorLayer（复制图层）。我们可以在复制图层里面添加一个instance图层，如果设置了复制图层的instanceCount，假如让instanceCount == 5， 那么复制图层会自动帮我们复制5个跟instance图层一样的图层（事实上，我们可以在一开始就给instance图层设置动画，那么在复制的时候，一样会把动画也复制过来），除此之外，还可以设置复制图层里面的instance图层的transfrom，从而实现一定的布局。复制图层里面还有一个instanceDelay，它表示延迟多少时间开始动画等等。

这个Demo就是用了上面所说的实现的，代码：

#import "ViewController.h" @interface ViewController () @property (weak, nonatomic) IBOutlet UIView *containView; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. [self setupReplicatorLayerAndAnimation]; } - (void)setupReplicatorLayerAndAnimation { CAReplicatorLayer *replicatorLayer = [CAReplicatorLayer layer]; replicatorLayer.frame = self.containView.layer.bounds; [self.containView.layer addSublayer:replicatorLayer]; CALayer *layer = [CALayer layer]; layer.frame = CGRectMake(self.containView.frame.size.width * 0.5, 20, 16, 16); layer.backgroundColor = [UIColor redColor].CGColor; layer.cornerRadius = layer.frame.size.width / 2; //这一句可以将初始过程移除掉 layer.transform = CATransform3DMakeScale(0, 0, 0); [replicatorLayer addSublayer:layer]; replicatorLayer.instanceCount = 22; CABasicAnimation *basicAn = [CABasicAnimation animationWithKeyPath:@"transform.scale"]; basicAn.fromValue = @1; basicAn.toValue = @0; basicAn.duration = 1; basicAn.repeatCount = MAXFLOAT; [layer addAnimation:basicAn forKey:nil]; replicatorLayer.instanceDelay = basicAn.duration / (double)replicatorLayer.instanceCount; replicatorLayer.instanceTransform = CATransform3DMakeRotation(2 * M_PI / replicatorLayer.instanceCount, 0, 0, 1); } @end

5、粒子效果

这个东西就是CAReplicatorLayer（复制图层）和Core Graphics的结合吧，我是采用UIBezierPath来绘制线条，然后将绘制好的path赋值给小球的animation路径，然后将小球添加到复制图层，设置下instanceCount，设置下延迟时间，效果就出来了。

代码：

#import "ZYDrawView.h" @interface ZYDrawView () @property (nonatomic, strong) UIBezierPath *bezierPath; @property (nonatomic, weak) CAReplicatorLayer *replicatorLayer; @property (nonatomic, weak) CALayer *norLayer; @end static int _count = 0; @implementation ZYDrawView - (UIBezierPath *)bezierPath { if (_bezierPath == nil) { _bezierPath = [[UIBezierPath alloc] init]; } return _bezierPath; } - (void)awakeFromNib { CAReplicatorLayer *replicatorLayer = [CAReplicatorLayer layer]; replicatorLayer.frame = self.bounds; [self.layer addSublayer:replicatorLayer]; CALayer *layer = [CALayer layer]; layer.frame = CGRectMake(0, -200, 10, 10); layer.cornerRadius = layer.frame.size.width * 0.5; layer.backgroundColor = [UIColor redColor].CGColor; [replicatorLayer addSublayer:layer]; self.replicatorLayer = replicatorLayer; self.norLayer = layer; } - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { CGPoint curPoint = [[touches anyObject] locationInView:self]; [self.bezierPath moveToPoint:curPoint]; } - (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { _count++; CGPoint curPoint = [[touches anyObject] locationInView:self]; [self.bezierPath addLineToPoint:curPoint]; [self setNeedsDisplay]; } - (void)startAnimation { CAKeyframeAnimation *keyframeAn = [CAKeyframeAnimation animationWithKeyPath:@"position"]; keyframeAn.path = self.bezierPath.CGPath; keyframeAn.duration = 4; keyframeAn.repeatCount = MAXFLOAT; [self.norLayer addAnimation:keyframeAn forKey:nil]; self.replicatorLayer.instanceCount = _count; self.replicatorLayer.instanceDelay = 0.1; } - (void)reDraw { _bezierPath = nil; _count = 1; [self.norLayer removeAllAnimations]; [self setNeedsDisplay]; } - (void)drawRect:(CGRect)rect { [self.bezierPath stroke]; } @end

以上内容是小编给大家介绍的Core Animation一些Demo总结 （动态切换图片、大转盘、图片折叠、进度条等动画效果），希望对大家以上帮助！

【Core Animation一些Demo总结 （动态切换图片、大转盘、图片折叠、进度条等动画效果）】相关文章：

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