iOS核心动画-属性动画

属性动画 CAPropertyAnimation 基类 不能直接使用
子类：
1.CABasicAnimation 基础动画
2.CAKeyframeAnimation 关键帧动画

通过改变图层或者视图上面的属性值（支持动画的属性）产生的动画
属性动画的常用方法属性
1.初始化

+ (instancetype)animationWithKeyPath:(nullable NSString *)path

path：需要产生动画的属性 如：中心点 -> 移动
2.KeyPath 描述 动画的属性

可以通过改变animationWithKeyPath来改变动画的属性：
改变动画的属性：

 transform.scale = 比例转换
 transform.scale.x
 transform.scale.y
 transform.rotation.z
 opacity   透明度
 zPosition
 backgroundColor 背景颜色
 cornerRadius 拐角
 borderWidth  边框的宽度
 bounds
 contents     内容
 contentsRect
 frame
 hidden
 masksToBounds
 opacity
 position
 shadowColor
 shadowOffset
 shadowOpacity
 shadowRadius

基础动画 CABasicAnimation
介绍：通过改变某个属性的值 到某个值 只能设置两个值 产生的动画
fromValue 开始值 如果不设置不会返回到初始位置
toValue 结束值
byValue 通过哪个值

心跳效果.gif

#import "ViewController.h"

@interface ViewController ()

//背景
@property(nonatomic,strong)CALayer *layer;
//花瓣
@property(nonatomic,strong)CALayer *petalLayer;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor blackColor];
    [self.view.layer addSublayer:self.layer];
//    [self.view.layer addSublayer:self.petalLayer];
    
}

-(CALayer *)layer{

    if (_layer) {
        return _layer;
    }
    _layer = [CALayer layer];
    _layer.position= CGPointMake(self.view.center.x, self.view.center.y+100);
    UIImage *image = [UIImage imageNamed:@"4"];
    _layer.bounds = CGRectMake(0, 0, image.size.width/2, image.size.height/2);
    _layer.contents = (id)image.CGImage;
    return _layer;
}
-(CALayer *)petalLayer{
    
    if (_petalLayer) {
        return _petalLayer;
    }
    _petalLayer = [CALayer layer];
    _petalLayer.position= CGPointMake(self.view.center.x, 50);
    UIImage *image = [UIImage imageNamed:@"2"];
    _petalLayer.bounds = CGRectMake(0, 0, image.size.width, image.size.height);
    _petalLayer.contents = (id)image.CGImage;
    return _petalLayer;
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

//    [self demo1:[[touches anyObject] locationInView:self.view]];
    [self demo2];
}

//移动中心点
-(void)demo1:(CGPoint)toValue{

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];
    //CGPoint -> 转id类型
    //CGPoint -> NSValue
    animation.fromValue = [NSValue valueWithCGPoint:self.petalLayer.position];
    //动画的持续时间
    animation.duration = 3;
    //动画执行的总时间 受动画速度的影响
//    animation.speed = 2;
    //设置动画完成的时候  固定在完成的状态
    //这个属性必须把removedOnCompletion 设置为NO 这个属性 才可以有效果
    animation.removedOnCompletion = NO;
    animation.toValue = [NSValue valueWithCGPoint:toValue];
    animation.fillMode = kCAFillModeBoth;
    //timingFunction可以控制动画的速度
    //快进慢出
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    //layer上添加动画效果 addAnimation: forKey:
    //forKey 表示动画的字符串 可以通过key 来找到这个动画
    [self.petalLayer addAnimation:animation forKey:@"可以通过这个key,找到此动画"];
    //查找某个key对应的动画
//    CABasicAnimation *an = (CABasicAnimation *)[self.petalLayer animationForKey:@"可以通过这个key,找到此动画"];
    
}
//心跳
-(void)demo2{
    self.view.backgroundColor = [UIColor whiteColor];
    UIImage *image = [UIImage imageNamed:@"心跳"];
    self.layer.contents = (id)image.CGImage;//为了方便，直接更换self.layer内容
    self.layer.bounds = CGRectMake(0, 0, image.size.width/10, image.size.height/10);
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"bounds"];
    /*
       目标
     1.放大后还原到原来的位置 以动画的方法
     2.先慢后快
     3.一直循环
     */
    animation.fromValue = [NSValue valueWithCGRect:self.layer.bounds];
    animation.toValue = [NSValue valueWithCGRect:CGRectMake(0, 0, image.size.width/5, image.size.height/5)];
    animation.repeatCount = HUGE;//无限循环
    animation.duration = 0.5;
    animation.autoreverses = YES;//以动画的效果返回到开始的状态
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    [self.layer addAnimation:animation forKey:@"heartJamp"];
}

---

花瓣飘落，心跳的效果

Demo：https://github.com/AmazingWow/CAPropertyAnimation--DEMO