CAGradientLayer实现渐变
1.colors 渐变的颜色
2.locations 渐变颜色的分割点
3.startPoint&endPoint 颜色渐变的方向,范围在(0,0)与(1.0,1.0)之间,如(0,0)(1.0,0)代表水平方向渐变,(0,0)(0,1.0)代表竖直方向渐变。
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.colors = @[(__bridge id)[UIColor colorWithHexString:@"#000000" alpha:0.4].CGColor, (__bridge id)[UIColor clearColor].CGColor];
//gradientLayer.locations = @[@0.3, @0.5, @1.0]; gradientLayer.startPoint = CGPointMake(0, 0);
gradientLayer.endPoint = CGPointMake(0, 1);
gradientLayer.frame = CGRectMake(0, 0, ScreenWidth, 25);
[topMaskView.layer addSublayer:gradientLayer];