iOS8之前的类不可用UIVisualEffectView

Question

我意识到我可以以编程方式添加UIVisualEffects,如果类存在则有条件地执行,例如.

if([UIVisualEffectView class]){

        UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
        UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
        [blurEffectView setFrame:self.backgroundBlurView.bounds];

        [self.backgroundBlurView addSubview:blurEffectView];

        UIVibrancyEffect *vibrancyEffect = [UIVibrancyEffect effectForBlurEffect:blurEffect];
        UIVisualEffectView *vibrancyEffectView = [[UIVisualEffectView alloc] initWithEffect:vibrancyEffect];
        [vibrancyEffectView setFrame:self.backgroundVibrancyView.bounds];

        [[vibrancyEffectView contentView] addSubview:self.backgroundVibrancyView];

        [[blurEffectView contentView] addSubview:vibrancyEffectView];
        vibrancyEffectView.center = blurEffectView.center;
    }

但有没有办法在故事板中添加视觉效果视图,然后有条件地删除它们以便与iOS7兼容？我试过这个,但一直得到这个错误: iOS8之前的类不可用UIVisualEffectView

Answer 1

没有。您可以将部署目标更改为 iOS 8+ 以消除错误：