iOS8中用UIVisualEffectView实现高斯模糊视图(毛玻璃效果)

UIBlurEffect *beffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];

UIVisualEffectView *view = [[UIVisualEffectView alloc]initWithEffect:beffect];

view.alpha = 0.7;

view.frame = self.bounds;

view.alpha 的透明度不能小于1；