仅在空投部分的底部更改UIActivityViewController背景颜色

class CustomActivityItemSource: NSObject, UIActivityItemSource {
    // 自定义分享内容和操作
    
    func activityViewControllerPlaceholderItem(_ activityViewController: UIActivityViewController) -> Any {
        return "" // 返回需要分享的内容
    }
    
    func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
        return "" // 返回需要分享的内容
    }
    
    // 自定义空投部分的底部背景颜色
    func activityViewControllerTintColor(_ activityViewController: UIActivityViewController) -> UIColor? {
        return UIColor.red // 设置底部背景颜色为红色
    }
}

// 在需要调用UIActivityViewController的地方
let customActivityItemSource = CustomActivityItemSource()
let activityViewController = UIActivityViewController(activityItems: ["分享内容"], applicationActivities: nil)
activityViewController.setValue(customActivityItemSource, forKey: "activityItemsSource")
self.present(activityViewController, animated: true, completion: nil)