发光动画

UIView *whiteView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[whiteView setBackgroundColor:[UIColor whiteColor]];
[whiteView setUserInteractionEnabled:NO];
[self.view addSubview:whiteView];

CALayer *maskLayer = [CALayer layer];

// Mask image ends with 0.15 opacity on both sides. Set the background color of the layer
// to the same value so the layer can extend the mask image.
maskLayer.backgroundColor = [[UIColor colorWithRed:1.0f green:1.0f blue:1.0f alpha:0.0f] CGColor];
maskLayer.contents = (id)[[UIImage imageNamed:@"ShineMask.png"] CGImage];

// Center the mask image on twice the width of the text layer, so it starts to the left
// of the text layer and moves to its right when we translate it by width.
maskLayer.contentsGravity = kCAGravityCenter;
maskLayer.frame = CGRectMake(-whiteView.frame.size.width,
                             0.0f,
                             whiteView.frame.size.width * 2,
                             whiteView.frame.size.height);

// Animate the mask layer's horizontal position
CABasicAnimation *maskAnim = [CABasicAnimation animationWithKeyPath:@"position.x"];
maskAnim.byValue = [NSNumber numberWithFloat:self.view.frame.size.width * 9];
maskAnim.repeatCount = HUGE_VALF;
maskAnim.duration = 3.0f;
[maskLayer addAnimation:maskAnim forKey:@"shineAnim"];

whiteView.layer.mask = maskLayer;