效果图

用到了 UIVisualEffectView

实现代码

- (UIVisualEffectView *)bgEffectView{if(!_bgEffectView){UIBlurEffect *blur = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];_bgEffectView = [[UIVisualEffectView alloc] initWithEffect:blur];}return _bgEffectView;
}

将 bgEffectView 盖到imageview上面即可

- (UIImageView *)bannerView
{if (!_bannerView) {_bannerView = [[UIImageView alloc] init];_bannerView.backgroundColor = [UIColor redColor];}return _bannerView;
}- (UIVisualEffectView *)bgEffectView{if(!_bgEffectView){UIBlurEffect *blur = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];_bgEffectView = [[UIVisualEffectView alloc] initWithEffect:blur];}return _bgEffectView;
}

   [self addSubview:self.bannerView];[self addSubview:self.bgEffectView];