【iOS进阶】【核心动画】2-CAKeyframeAnimation

CAKeyframeAnimation提供关键帧支持，可以为动画层属性制定一个关键路径，路径可以是一个数组，保存动画的每一个阶段值和关键的帧动画次数和时间。

1、values

　　values：就是上述的NSArray对象。里面的元素称为”关键帧”(keyframe)。

　　动画对象会在指定的时间(duration)内，依次显示values数组中的每一个关键帧

//CAKeyframeAnimation能在任意多个值之间切换
    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
    
    anim.keyPath = @"position";
    
    NSValue *v1 = [NSValue valueWithCGPoint:CGPointMake(0, 0)];
    NSValue *v2 = [NSValue valueWithCGPoint:CGPointMake(100, 0)];
    NSValue *v3 = [NSValue valueWithCGPoint:CGPointMake(0, 100)];
    NSValue *v4 = [NSValue valueWithCGPoint:CGPointMake(100, 100)];
    anim.values =@[v1,v2,v3,v4];
    
    anim.duration = 2.0;
    
    anim.removedOnCompletion = NO;
    anim.fillMode = kCAFillModeForwards;
    
    [self.blockView.layer addAnimation:anim forKey:nil];

2、path

　　path：可以设置一个CGPathRef\CGMutablePathRef,让层跟着路径移动。

　　path只对CALayer的anchorPoint和position起作用。如果你设置了path，那么values将被忽略

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
    
    anim.keyPath = @"position";
    anim.removedOnCompletion = NO;
    anim.fillMode = kCAFillModeForwards;
    anim.duration = 3.0;
    //设置监听
    anim.delegate = self;
    
    //创建一个路径
    CGMutablePathRef path = CGPathCreateMutable();
    //往路径里面添加一个圆
    CGPathAddEllipseInRect(path, NULL, CGRectMake(100, 100, 150, 150));
    
    //设置动画的路径
    anim.path = path;
    
    //Create创建的都要Release
    CGPathRelease(path);
    
    //设置动画的执行节奏
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
    
    [self.blockView.layer addAnimation:anim forKey:nil];

 3> 模拟图标抖动的示例

//定义角度制转换成弧度制的宏
#define Angle2Radian(angle) (M_PI * ((angle)/180.0))

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
- (IBAction)start;
- (IBAction)stop;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad]; 
}

- (IBAction)start {

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
    anim.keyPath = @"transform.rotation";
    anim.removedOnCompletion = NO;
    anim.fillMode = kCAFillModeForwards;
    
    anim.values = @[@(Angle2Radian(-10)),@(Angle2Radian(10)),@(Angle2Radian(-10))];
    
    anim.duration = 0.3;
    
    //重复次数
    anim.repeatCount = MAXFLOAT;
    
    [self.imageView.layer addAnimation:anim forKey:@"hehe"];

}

- (IBAction)stop {
    //根据key删除相应的动画
    [self.imageView.layer removeAnimationForKey:@"hehe"];
}
@end