iOS学习-实现view的渐变色

CAGradientLayer *gradient = [CAGradientLayer layer];

gradient.frame =CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);

gradient.colors = [NSArray arrayWithObjects:

(id)[UIColor whiteColor].CGColor,

(id)[UIColor grayColor].CGColor,

(id)[UIColor whiteColor].CGColor,

nil];

[self.view.layer insertSublayer:gradient atIndex:0];