ios - 仅用于背景的 CAGradientLayer

Question

我正在为我的 View 背景设置渐变:

CAGradientLayer *grad = [CAGradientLayer layer];
grad.frame = self.contentView.frame;
grad.colors = @[(id)[[UIColor colorWithRed:1.0f green:0.5f blue:0.5f alpha:0.0f] CGColor],
                (id)[[UIColor colorWithWhite:1.0f alpha:0.5f] CGColor],
                (id)[[UIColor colorWithWhite:1.0f alpha:0.8f] CGColor],
                (id)[[UIColor colorWithWhite:0.0f alpha:1.0f] CGColor]];
grad.locations = @[@0.00f, @0.5f, @0.7f, @1.00f];        
self.layer.mask = grad;

问题是，我 View 顶部的每个元素(UIButton、UILabel...)都具有与父级相同的梯度。如何仅为 View 设置渐变，而不为该 View 上的项目设置渐变？

Answer 1

您可以将渐变设置为 View 的子层，而不是设置 mask ，如下所示:

 [self.view setBackgroundColor:[UIColor clearColor]]; 
 [self.view.layer insertSublayer:grad atIndex:0];