scrollview键盘弹起时推起底部的textfield示例（

import UIKit

class ViewController: UIViewController ,UIScrollViewDelegate {
  @IBOutlet weak var fgScrollView: UIScrollView!
    
  override func viewDidLoad() {
    super.viewDidLoad()

    let center = NotificationCenter.default//默认通知中心
    //分别增加观察者以便监听两个事件--keyboardwillshow,keyboardwillhide
    center.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: Notification.Name.UIKeyboardWillShow, object: nil)
    
    center.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: Notification.Name.UIKeyboardWillHide , object: nil)
    
    }
    //控制器销毁的时候同时销毁观察者
    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
    //监听键盘显示事件
    @objc func keyboardWillShow(notification:Notification){
        //获取用户信息--字典类型
        let userInfo = notification.userInfo ?? [:]
        //获取键盘的高度
        let keyboardHeight = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue.height
        
        //设定scrollview的底部内边距(搜狗输入法的键盘有点bug，第一次弹出的时候实际键盘高度比获取到的要高，第二次就没问题。总之我还是加上个30吧)
        fgScrollView.contentInset.bottom = keyboardHeight + 30   
    }
    //监听键盘收起事件
    @objc func keyboardWillHide(notification:Notification){
        fgScrollView.contentInset.bottom = 0
    }

}