我想在我的drawRect中添加一个CAGradientLayer,代码如下:
- (void)drawRect:(CGRect)rect {
CAGradientLayer *gradientOverlay = [CAGradientLayer layer];
CGColorRef grayColor = [UIColor colorWithRed:37/255.f green:37/255.f
blue:37/255.f alpha:1.0].CGColor;
CGColorRef blueColor = [UIColor colorWithRed:23.0/255.0 green:171.0/255.0
blue:219.0/255.0 alpha:1.0].CGColor;
gradientOverlay.colors = [NSArray arrayWithObjects:
(id) grayColor,
(id) grayColor,
(id) blueColor,
nil];
gradientOverlay.locations = [NSArray arrayWithObjects:
[NSNumber numberWithFloat:0],
[NSNumber numberWithFloat:0.4],
[NSNumber numberWithFloat:1],
nil];
CGPoint startPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
CGPoint endPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
gradientOverlay.startPoint = startPoint;
gradientOverlay.frame = self.bounds;
gradientOverlay.endPoint = endPoint;
self.layer.mask = gradientOverlay;
}
知道为什么这不起作用吗?