當我更新contentInset時，UIScrollView會更改contentOffset

Question

UIScrollView固定在控制器的視圖邊緣。

在UIKeyboardWillShow我通過增加鍵盤高度來增加contentInsets底值。 動畫制作完成后，內容將沿向上方向稍微滾動。

if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double ?? 0.3
    self.formContainer.contentInset = UIEdgeInsets(top: self.rowPadding, left: 0, bottom: keyboardSize.height + self.navigator.frame.height + 10, right: 0)
    self.navigatorBottom.constant = -keyboardSize.height
    UIView.animate(withDuration: duration) {
        self.view.layoutIfNeeded()
    }
}

無論如何，這里有禁止內容滾動的功能嗎？

Answer 1

在開始動畫之前保存UIScrollView contentOffset並將動畫completionHandler保存值設置為contentOffset

看起來像這樣：

if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double ?? 0.3
    let currentContentOffset = self.formContainer.contentOffset.y //assume your scrollView scrolls vertically
    self.formContainer.contentInset = UIEdgeInsets(top: self.rowPadding, left: 0, bottom: keyboardSize.height + self.navigator.frame.height + 10, right: 0)
    self.navigatorBottom.constant = -keyboardSize.height
    UIView.animate(withDuration: duration, animations: {
        self.view.layoutIfNeeded()
    }) { _ in
        self.formContainer.contentOffset.y = currentContentOffset
    }
}