弹簧动画

看过我前两篇博客的都知道此次要将的弹簧动画（CASpringAnimation）是基于基础动画CABaseAnimation

CASpringAnimation:弹簧动画->属于基础动画CABaseAnimation的子类

CABaseAnimation只能设置fromValue和toValue/byValue

下面讲一下CASpringAnimation弹簧动画常用的属性

mass:质量 ->影响图层运动的弹簧惯性,质量越大，幅度越大

 stiffness刚度（经度/弹性）刚度越大，形变产生的力就越大，运动越快

 damping：阻力，阻力越大，停止越快

 initialVelocity：初始速率，动画视图的初始速度大小速率为正数时，速度方向与运动方向相同，初始速度大小速率为负数时，速度方向与运动方向相反

 settlingDuration 获得动画完成的预估时间

具体代码：

#import "ViewController.h"

@interfaceViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

  

}

//创建弹簧动画的方法

- (void)move:(CGPoint)position{

/*

 CASpringAnimation：父类CABaseAnimation->父类CAPropertyAnimation

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

 */

    

    CASpringAnimation *springAn = [CASpringAnimationanimationWithKeyPath:@"position"];

    

    springAn.fromValue = [NSValuevalueWithCGPoint:self.imageView.center];

    

    springAn.toValue = [NSValuevalueWithCGPoint:position];

    

//    设置fillModel必须把removedOnCompletion设为NO

    springAn.removedOnCompletion =NO;

    springAn.fillMode =kCAFillModeBoth;

    

    /*

     mass 质量

     stiffness 刚度

     damping 阻力

     initialVelocity 初始速率

     settlingDuration 获得动画完成的预估时间

     

     */

//    质量

    springAn.mass =100;

//   刚度，刚度越大，运动速度越快

    springAn.stiffness =5;

//    阻力，摩擦力

    springAn.damping =2;

//    初始速率

    springAn.initialVelocity =0;

//将获得弹簧的预估时间赋给持续时间

    springAn.duration = springAn.settlingDuration;

    

//  将动画添加到图层

    [self.imageView.layeraddAnimation:springAnforKey:@"move"];

    

    

}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    [selfmove:[[touchesanyObject]locationInView:self.view]];

}

弹簧动画的另外一种效果代码

#import "ViewController.h"

@interfaceViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

   

}

- (void)didReceiveMemoryWarning {

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

- (IBAction)button:(id)sender {

     UIButton *button = sender;

    button.selected = !button.selected;

    

    button.backgroundColor = button.selected !=YES ? [UIColorredColor]:[UIColorcyanColor];

    [selfjamp];

}

- (void)jamp{

    CASpringAnimation *animation = [CASpringAnimationanimationWithKeyPath:@"bounds"];

    

    animation.toValue = [NSValuevalueWithCGRect:CGRectMake(0,0,CGRectGetWidth(self.myButton.frame)*1.5,CGRectGetHeight(self.myButton.frame)*1.5)];

    animation.mass =2;

    animation.damping =3;

    animation.initialVelocity =30;

    animation.stiffness =100;

    animation.duration = animation.settlingDuration;

    [self.myButton.layeraddAnimation:animationforKey:@"jamp"];

}

- (void)move:(CGPoint)toPoint{

    CABasicAnimation *animation = [CABasicAnimationanimationWithKeyPath:@"position"];

    animation.toValue = [NSValuevalueWithCGPoint:toPoint];

    animation.duration =1;

    animation.removedOnCompletion =NSNotFound;

    animation.fillMode =kCAFillModeBoth;

    [self.myButton.layeraddAnimation:animationforKey:@""];

}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    NSLog(@"buttong改变位置之前的中心点%f %f",self.myButton.center.x,self.myButton.center.y);

     NSLog(@"buttong上面layer的中心点%f %f",self.myButton.layer.position.x,self.myButton.layer.position.y);

  

    [selfmove:[[touchesanyObject]locationInView:self.view]];

    NSLog(@"buttong改变位置之后的中心点%f %f",self.myButton.center.x,self.myButton.center.y);

    /*

     CAAnimation只是改变图层的动画效果，并没有真是我的改变图层视图的属性值

     

     */

}

@end