ios 以后毛玻璃

 UIBlurEffect *blur = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];

        UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:blur];

        effectView.alpha = 0.9;

        effectView.frame = CGRectMake(0.0, 0.0, MAIN_SCREEN_WIDTH, MAIN_SCREEN_HEIGHT);

        [self.view insertSubview:effectView atIndex:0];