关于 Core Animation

Core Animation是一组非常强大的动画处理API,使用它能做出很多优雅的动画效果。能用的动画类有4个子类：CABasicAnimation、CAKeyframeAnimation、CATransition、CAAnimationGroup

开发步骤:

1. 初始化一个动画对象(CAAnimation)并设置一些动画相关属性.

2. 添加动画对象到层(CALayer)中,开始执行动画.

CALayer中很多属性都可以通过CAAnimation实现动画效果, 包括opacity, position, transform, bounds, contents等，具体可以在API文档中查找

通过调用CALayer的addAnimation:forKey:增加动画到层(CALayer)中,这样就能触发动画了.通过调用removeAnimationForKey:可以停止层中的动画.

注：Core Animation的动画执行过程都是在后台操作的,不会阻塞主线程.

创建动画时你可能用到的属性

巧妙的运用这些可以属性实现很棒的动画效果，比如下面：用CABasicAnimation实现的动画

CABasicAnimation动画

简单的呼吸和摇摆动画

animation.gif

简单的代码

 1.呼吸动画CABasicAnimation *animation =[CABasicAnimation animationWithKeyPath:@"opacity"];animation.fromValue = [NSNumber numberWithFloat:1.0f];animation.toValue = [NSNumber numberWithFloat:0.0f];animation.autoreverses = YES;    //回退动画（动画可逆，即循环）animation.duration = 1.0f;animation.repeatCount = MAXFLOAT;animation.removedOnCompletion = NO;animation.fillMode = kCAFillModeForwards;//removedOnCompletion,fillMode配合使用保持动画完成效果animation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];[self.alphaTagButton.layer addAnimation:animation forKey:@"aAlpha"];  2.摇摆动画//设置旋转原点self.sharkTagButton.layer.anchorPoint = CGPointMake(0.5, 0);CABasicAnimation* rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];//角度转弧度（这里用1，-1简单处理一下）rotationAnimation.toValue = [NSNumber numberWithFloat:1];rotationAnimation.fromValue = [NSNumber numberWithFloat:-1];rotationAnimation.duration = 1.0f;rotationAnimation.repeatCount = MAXFLOAT;rotationAnimation.removedOnCompletion = NO;rotationAnimation.autoreverses = YES;rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];rotationAnimation.fillMode = kCAFillModeForwards;[self.sharkTagButton.layer addAnimation:rotationAnimation forKey:@"revItUpAnimation"];

陀螺仪&加速仪的动画

ps:好吧 这个属于乱入，和上面的摇摆动画差不多的效果，只是这个是手动的 哈哈

3、陀螺仪&加速仪的动画self.motionManager = [[CMMotionManager alloc] init];self.motionManager.deviceMotionUpdateInterval = 1.0f/100.0f; //1秒100次self.sharkTagButton.layer.anchorPoint = CGPointMake(0.5, 0);[self.motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMDeviceMotion *motion, NSError *error) {if(fabs(motion.attitude.roll)<1.0f){[UIView animateWithDuration:0.6 animations:^{self.sharkTagButton.layer.transform = CATransform3DMakeRotation(-(motion.attitude.roll), 0, 0, 1);}];}else if (fabs(motion.attitude.roll)<1.5f){[UIView animateWithDuration:0.6 animations:^{int s;if (motion.attitude.roll>0){s=-1;}else{s = 1;}self.sharkTagButton.layer.transform = CATransform3DMakeRotation(s*M_PI_2, 0, 0, 1);}];}if ((motion.attitude.pitch)<0){[UIView animateWithDuration:0.6 animations:^{self.sharkTagButton.layer.transform = CATransform3DMakeRotation(M_PI, 0, 0, 1);}];}}];

Demo地址：
https://github.com/yongliangP/CABasicAnimationDemo

CATransition之简单的转场动画

CAAnimation的子类，用于做转场动画，能够为层提供移出屏幕和移入屏幕的动画效果。

• 常用动画类型:

注：私有API只能通过字符串使用哈

• 过渡方向参数:

简单的CATransition动画

CATransitionDemo2.gif

-(void)animationWithType:(NSString*)type
{//- 创建一个转场动画:CATransition *transition = [CATransition animation];transition.repeatCount = 5;//    - 确定动画类型:transition.type = type;//    - 确定子类型(方向等)transition.subtype = kCATransitionFromLeft;//    - 确定动画时间transition.duration = 1;//    - 添加动画[self.imageView.layer addAnimation:transition forKey:nil];}

使用时只用传你的想要的动画类型就好，私有API只能通过字符串使用哈。

[self animationWithType:self.dataArray[indexPath.row]];

DEMO地址：https://github.com/yongliangP/CATransitionDemo

---20160908更新

CAKeyframeAnimation

先看图，就是那个在跑的小圆球，为了方便，把动画集成在了一个Demo里了

ScreenShotDemo2.gif

• 1 .简单介绍

  CAKeyframeAnimation是CApropertyAnimation的子类，跟CABasicAnimation的区别是：CABasicAnimation只能从一个数值(fromValue)变到另一个数值(toValue)，而CAKeyframeAnimation会使用一个NSArray保存这些数值，是一种更灵活的动画方式。

• 2 .属性介绍

• 3 .实现
  • 3.1 values方式实现

-(void)setUpCAKeyframeAnimationUseValues
{CAKeyframeAnimation *animation = [CAKeyframeAnimation animation];animation.keyPath = @"position";NSValue *value1 = [NSValue valueWithCGPoint:CGPointMake(50, 50)];NSValue *value2 = [NSValue valueWithCGPoint:CGPointMake(kWindowWidth - 50, 50)];NSValue *value3 = [NSValue valueWithCGPoint:CGPointMake(kWindowWidth - 50, kWindowHeight-50)];NSValue *value4 = [NSValue valueWithCGPoint:CGPointMake(50, kWindowHeight-50)];NSValue *value5 = [NSValue valueWithCGPoint:CGPointMake(50, 50)];animation.values = @[value1,value2,value3,value4,value5];animation.repeatCount = MAXFLOAT;animation.removedOnCompletion = NO;animation.fillMode = kCAFillModeForwards;animation.duration = 6.0f;animation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];[self.keyButton.layer addAnimation:animation forKey:@"values"];}

• 3.2 path方式实现

-(void)setUpCAKeyframeAnimationUsePath
{CAKeyframeAnimation *animation = [CAKeyframeAnimation animation];animation.keyPath = @"position";CGMutablePathRef path = CGPathCreateMutable();//矩形线路CGPathAddRect(path, NULL, CGRectMake(50,50, kWindowWidth - 100,kWindowHeight - 100));animation.path=path;CGPathRelease(path);animation.repeatCount = MAXFLOAT;animation.removedOnCompletion = NO;animation.fillMode = kCAFillModeForwards;animation.duration = 10.0f;animation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];[self.keyButton.layer addAnimation:animation forKey:@"path"];}

• 3.3 keyTimes演示

-(void)setUpCAKeyframeAnimationUsekeyTimes
{CAKeyframeAnimation *animation = [CAKeyframeAnimation animation];
//    animation.keyPath = @"transform.translation.x";animation.keyPath = @"position.x";animation.values = @[@0, @20, @-20, @20, @0];animation.keyTimes = @[ @0, @(1 / 6.0), @(3 / 6.0), @(5 / 6.0), @1 ];animation.duration = 0.5;animation.additive = YES;[self.sharkTagButton.layer addAnimation:animation forKey:@"keyTimes"];}

---20160921更新

CAAnimationGroup

看图，就是那个下方的小长方形，简单实现

ScreenShotGroupDemo.gif

动画组，顾名思义就是动画的组合，具体动画可以参考上文，不同的脑洞会出现不同的化学反应。

简单示例：

    CABasicAnimation * animationScale = [CABasicAnimation animation];animationScale.keyPath = @"transform.scale";animationScale.toValue = @(0.1);CABasicAnimation *animationRota = [CABasicAnimation animation];animationRota.keyPath = @"transform.rotation";animationRota.toValue = @(M_PI_2);CAAnimationGroup * group = [[CAAnimationGroup alloc] init];group.duration = 3.0;group.fillMode = kCAFillModeForwards;group.removedOnCompletion = NO;group.repeatCount = MAXFLOAT;group.animations = @[animationScale,animationRota];[self.groupButton.layer addAnimation:group forKey:nil];

Demo传送门

附：关于keyPath你可能用到的属性

照例放Demo
Demo地址：
https://github.com/yongliangP/CABasicAnimationDemo
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