脉冲效果

#import <QuartzCore/QuartzCore.h>

@interface PulsatorLayer : CAReplicatorLayer

@property(nonatomic, assign) CGColorRef outColor;
@property(nonatomic, assign) CGColorRef inColor;

@property(nonatomic, assign) CGFloat animationDuration;
@property(nonatomic, assign) CGFloat animationInterval;
//0~1
@property(nonatomic, assign) CGFloat maxAlpha;
@property(nonatomic, assign) CGFloat minAlpha;
//0~1
@property(nonatomic, assign) CGFloat maxScale;
@property(nonatomic, assign) CGFloat minScale;

@property(nonatomic, assign) NSInteger count;

@property(nonatomic, assign) CGFloat maxRadius;
@property(nonatomic, assign) BOOL isAnimation;

-(void)startAnimation;

-(void)stopAnimation;

@end

#import "PulsatorLayer.h"

static NSString *kPulseAnimationKey = @"PulseAnimationKey";

@interface PulsatorLayer ()

@property (nonatomic, strong) CAShapeLayer *pulseLayer;

@end

@implementation PulsatorLayer

- (instancetype)init {
    self = [super init];
    if (self) {
        self.animationDuration = 5;
        self.animationInterval = 1;
        self.maxAlpha = 0.7;
        self.minAlpha = 0.1;
        self.maxScale = 1.0;
        self.minScale = 0.3;
        self.count = 5;
        self.maxRadius = 50;
        
        self.instanceCount = _count;
        self.instanceDelay = (self.animationDuration+self.animationInterval) / (CGFloat)_count;
        self.repeatCount = MAXFLOAT;
        
        [self addSublayer:self.pulseLayer];
    }
    return self;
}

- (CAShapeLayer *)pulseLayer {
    if (!_pulseLayer) {
        CAShapeLayer *pulseLayer = [CAShapeLayer layer];
        pulseLayer.backgroundColor = self.outColor;
        pulseLayer.contentsScale = [UIScreen mainScreen].scale;
        pulseLayer.cornerRadius = self.maxRadius;
        pulseLayer.bounds = CGRectMake(0, 0, self.maxRadius*2, self.maxRadius*2);
        pulseLayer.opacity = 0.0;
        _pulseLayer = pulseLayer;
    }
    return _pulseLayer;
}

- (void)setFrame:(CGRect)frame {
    [super setFrame:frame];
}

-(void)setMaxRadius:(CGFloat)maxRadius {
    _maxRadius = maxRadius;
    if (_pulseLayer) {
        CGRect bounds = _pulseLayer.bounds;
        bounds.size.width = maxRadius*2;
        bounds.origin.x = self.frame.origin.x;
        bounds.origin.y = self.frame.origin.y;
        bounds.size.height = maxRadius*2;
        _pulseLayer.bounds = bounds;
        _pulseLayer.cornerRadius = maxRadius;
    }
}



//开始动画
-(void)startAnimation {
    if (self.isAnimation) {
        return;
    }
    //透明度
    CABasicAnimation *opacityAnima = [CABasicAnimation animationWithKeyPath:@"opacity"];
    opacityAnima.duration = self.animationDuration;
    opacityAnima.fromValue = @(self.maxAlpha);
    opacityAnima.toValue = @(self.minAlpha);
    opacityAnima.removedOnCompletion = NO;
    opacityAnima.cumulative = YES;
    //脉冲源大小(layer*0.3)
    CABasicAnimation *scaleAnima = [CABasicAnimation animationWithKeyPath:@"transform"];
    scaleAnima.duration = self.animationDuration;
    scaleAnima.fromValue = [NSValue valueWithCATransform3D:CATransform3DScale(CATransform3DIdentity, self.minScale, self.minScale, 0.0)];
    scaleAnima.toValue = [NSValue valueWithCATransform3D:CATransform3DScale(CATransform3DIdentity, self.maxScale, self.maxScale, 0.0)];
    scaleAnima.removedOnCompletion = NO;
    scaleAnima.cumulative = YES;
    //颜色
    CABasicAnimation *colorAnima = [CABasicAnimation animationWithKeyPath:@"backgroundColor"];
    colorAnima.duration = self.animationDuration;
    colorAnima.fromValue = (__bridge id _Nullable)(self.inColor);
    colorAnima.toValue = (__bridge id _Nullable)(self.outColor);
    colorAnima.removedOnCompletion = NO;
    colorAnima.cumulative = YES;
    
    CAAnimationGroup *groupAnima = [CAAnimationGroup animation];
    groupAnima.animations = @[opacityAnima, scaleAnima, colorAnima];
    groupAnima.duration = self.animationDuration+self.animationInterval;
    groupAnima.autoreverses = NO;//动画回退
    groupAnima.removedOnCompletion = NO;
    groupAnima.repeatCount = MAXFLOAT;
    self.isAnimation = YES;
    [self.pulseLayer addAnimation:groupAnima forKey:kPulseAnimationKey];
}


-(void)stopAnimation {
    self.isAnimation = NO;
   [self removeAnimationForKey:kPulseAnimationKey]; 
}

@end