显示和隐藏键盘时的 UITableView 部分页脚问题

Question

我有一个带有节页眉和页脚的UITableView。在一个单元格中，我有一个 UITextField，它触发键盘的显示。

当键盘出现时，只有有时（它以某种方式取决于表格的滚动位置）最后一节页脚正确地向上移动，所以这个页脚出现在 keyboard 的正上方。

但是当我再次隐藏键盘时，页脚会停留在这个位置，直到通过进一步的用户交互刷新表格。我怎样才能避免这种情况，或者至少以编程方式强制刷新？

tableView.reloadData() 没有帮助。

请注意，它只发生在 iPhone 上，而不是 iPad。到目前为止仅使用 iOS 12.2 进行了测试。

Answer 1

override func viewWillAppear(_ animated: Bool) {
    self.registerForKeyboardNotifications()
    super.viewWillAppear(animated)
}

override func viewWillDisappear(_ animated: Bool) {
    self.deregisterFromKeyboardNotifications()
    super.viewWillDisappear(animated)
}



func registerForKeyboardNotifications(){
    //Adding notifies on keyboard appearing
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name:
        UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}

func deregisterFromKeyboardNotifications(){
    //Removing notifies on keyboard appearing
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}


@objc func keyboardWasShown(notification: NSNotification){

    //Need to calculate keyboard exact size due to Apple suggestions
    var info = notification.userInfo!
    let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue
    //let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardSize!.size.height, right: 0.0)
}

@objc func keyboardWillBeHidden(notification: NSNotification){
    //Once keyboard disappears, restore original positions
    //var info = notification.userInfo!
    //let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
    //let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: -keyboardSize!.height, right: 0.0)

     tableview.transform = CGAffineTransformMakeScale(1, -1);

}