雷达效果

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@interface ViewController ()

{

    CALayer *_layer;

    CAAnimationGroup *_animaTionGroup;

    CADisplayLink *_disPlayLink;

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

- (void)startAnimation

{

    CALayer *layer = [[CALayer alloc] init];

    layer.cornerRadius = [UIScreen mainScreen].bounds.size.width/2;

    layer.frame = CGRectMake(0, 0, layer.cornerRadius * 2, layer.cornerRadius * 2);

    layer.position = self.view.layer.position;

    UIColor *color = [UIColor colorWithRed:arc4random()%10*0.1 green:arc4random()%10*0.1 blue:arc4random()%10*0.1 alpha:1];

    layer.backgroundColor = color.CGColor;

    [self.view.layer addSublayer:layer];

    CAMediaTimingFunction *defaultCurve = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];

    _animaTionGroup = [CAAnimationGroup animation];

    _animaTionGroup.delegate = self;

    _animaTionGroup.duration = 2;

    _animaTionGroup.removedOnCompletion = YES;

    _animaTionGroup.timingFunction = defaultCurve;

    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale.xy"];

    scaleAnimation.fromValue = @0.0;

    scaleAnimation.toValue = @1.0;

    scaleAnimation.duration = 2;

    CAKeyframeAnimation *opencityAnimation = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];

    opencityAnimation.duration = 2;

    opencityAnimation.values = @[@0.8,@0.4,@0.0];

    opencityAnimation.keyTimes = @[@0,@0.5,@1];

    opencityAnimation.removedOnCompletion = YES;

    NSArray *animations = @[scaleAnimation,opencityAnimation];

    _animaTionGroup.animations = animations;

    [layer addAnimation:_animaTionGroup forKey:nil];

    [self performSelector:@selector(removeLayer:) withObject:layer afterDelay:1.5];

}

- (void)removeLayer:(CALayer *)layer

{

    [layer removeFromSuperlayer];

}

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

{

    _disPlayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(delayAnimation)];

    _disPlayLink.frameInterval = 40;

    [_disPlayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

}

- (void)delayAnimation

{

    [self startAnimation];

}

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

{

    [self.view.layer removeAllAnimations];

    [_disPlayLink invalidate];

    _disPlayLink = nil;

}

雷达效果

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原文地址：http://www.cnblogs.com/sgdkg/p/5162750.html