iOS系统分享（支持iPad）

代码：

func systemShare(items:[Any],viewController:UIViewController){
    let activityVC = UIActivityViewController(
        activityItems: items,
        applicationActivities: nil)
    activityVC.popoverPresentationController?.sourceView = viewController.view
    activityVC.popoverPresentationController?.sourceRect = CGRect(x: screenWidth / 2, y: screenHeight / 2, width: 1, height: 1)
    activityVC.popoverPresentationController?.permittedArrowDirections = .up
    activityVC.completionWithItemsHandler =  { activity, success, items, error in
        activityVC.dismiss(animated: true, completion: nil)
    }
    viewController.present(activityVC, animated: true, completion: nil)
}

注意点：

图文链接分享到QQ后只有链接分享成功，点击复制后在微信粘贴只能分享图片，是QQ和微信自己处理时的选择，不是bug