3、 简单使用CoreAnimation的步骤

KeyPath常用的属性：

• kCAMediaTimingFunctionLinear，在整个动画时间内动画都是以一个相同的速度来改变，也就是匀速运动。一个线性的计时函数，同样也是CAAnimation的timingFunction属性为空时候的默认函数。线性步调对于那些立即加速并且保持匀速到达终点的场景会有意义（例如射出枪膛的子弹）。

/* CABasicAnimation应用

    心跳效果

    思路:就是让一张图片做一个放大缩放小的动画.

*/

//代码实现:

- (void) viewDidLoad {

    CABasicAnimation *anim =[CABasicAnimation  animation];

    //设置缩放属性

    anim.keyPath = @"transform.scale";

    //缩放到一半

    anim.toValue = @0.5;

    //设置动画执行的次数

    anim.repeatCount = MAXFLOAT;

    //设置动画执行的时长

    anim.duration = 0.25;

    //设置动画自动反转(怎么去, 怎么回)

    anim.autoreverses = YES;

    //添加动画

    [self.heartView.layer addAnimation:anim forKey:nil];

}

/* CAKeyframeAnimation的应用

    图片抖动

    思路：其实就是做一个左右旋转的动画.先让它往左边旋转-5,再往右边旋转5度,再从5度旋转到-5度. 就会有左右摇摆的效果了.

*/

//图标抖动代码实现

- (void)values{

    //创建一个帧动画

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];

    //设置属性

    anim.keyPath = @"transform.rotation";

    //设置属性值.

    anim.values = @[@(angle2Rad(-)),@(angle2Rad()),@(angle2Rad(-))];

    //设置执行的次数

    anim.repeatCount = MAXFLOAT;

    anim.duration = 0.25;

    //添加动画

    [self.iconV.layer addAnimation:anim forKey:nil];

}

//我们还可以直接设置关键帧CAKeyframeAnimation动画的路径 path属性

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

    //创建一个帧动画

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];

    //设置属性

    anim.keyPath = @"position";

    //直接设置动画的路径path是画弧

    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(, , , )];

    anim.path = path.CGPath;

    //设置执行的次数

    anim.repeatCount = MAXFLOAT;

   //设置是否反转

    anim.autoreverses = YES;

    anim.duration = ;

    //添加动画

    [self.iconV.layer addAnimation:anim forKey:nil];

}

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

    //UIView执行转场动画

    [UIView transitionWithView:self.imageV duration: options:UIViewAnimationOptionTransitionCrossDissolve animations:^{

        _i++;

        if (_i > ) {

            _i = ;

        }

        NSString *imageName = [NSString stringWithFormat:@"%d",_i];

        self.imageV.image = [UIImage imageNamed:imageName];

    } completion:nil];    

}

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

    //转场代码必须得要和转场动画在同一个方法当中.

    //创建动画

    CATransition *anim = [CATransition animation];

    //设置转场类型

    anim.type = @"cube";

    //设置转场的方向

    anim.subtype = kCATransitionFromTop;

    //设置动画的开始点.

    anim.startProgress = 0.2;

    //设置动画的结束点.

    anim.endProgress = 0.8;

    [self.imageV.layer addAnimation:anim forKey:nil];

    //转场代码必须得要和转场动画在同一个方法当中.

    _i++;

    if (_i > ) {

        _i = ;

    }

    NSString *imageName = [NSString stringWithFormat:@"%d",_i];

    self.imageV.image = [UIImage imageNamed:imageName];

}

- (void)springAni {

    CASpringAnimation * ani = [CASpringAnimation animationWithKeyPath:@"bounds"];

    ani.mass = 10.0; //质量，影响图层运动时的弹簧惯性，质量越大，弹簧拉伸和压缩的幅度越大

    ani.stiffness = ; //刚度系数(劲度系数/弹性系数)，刚度系数越大，形变产生的力就越大，运动越快

    ani.damping = 100.0;//阻尼系数，阻止弹簧伸缩的系数，阻尼系数越大，停止越快

    ani.initialVelocity = .f;//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一致，速率为负数时，速度方向与运动方向相反

    ani.duration = ani.settlingDuration;

    ani.toValue = [NSValue valueWithCGRect:self.centerShow.bounds];

    ani.removedOnCompletion = NO;

    ani.fillMode = kCAFillModeForwards;

    ani.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    [self.cartCenter.layer addAnimation:ani forKey:@"boundsAni"];

}

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

    CAAnimationGroup *group = [CAAnimationGroup animation];

    //缩放

    CABasicAnimation *scaleAnim = [CABasicAnimation animation];

    //设置属性

    scaleAnim.keyPath = @"transform.scale";

    scaleAnim.toValue = @0.5;

    //平移

    CABasicAnimation *Anim = [CABasicAnimation animation];

    //设置属性

    Anim.keyPath = @"position.y";

    Anim.toValue = @();

    //将上面两个动画添加到动画组

    group.animations = @[scaleAnim,Anim];

    //设置动画的属性，一定要在动画组上设置

    group.removedOnCompletion = NO;

    group.fillMode  = kCAFillModeForwards;

    //添加动画

    [self.redView.layer addAnimation:group forKey:nil];

}