Question

我有一个UIView固定在我的superview的底部。它具有一个文本视图，在被点击时将成为第一响应者。此时，我检测到键盘将显示并更改其底部约束以将其向上移动，使其位于键盘上方。我使用以下代码来做到这一点：

private func keyboardWillShow(_ aNotification: Notification) {
    guard let info = (aNotification as NSNotification).userInfo,
        let endFrame = (info as NSDictionary).value(forKey: UIResponder.keyboardFrameEndUserInfoKey),
        let currentKeyboard = (endFrame as AnyObject).cgRectValue,
        let rate = info[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber
        else { return }

    let convertedFrame = self.view.convert(currentKeyboard, from: UIScreen.main.coordinateSpace)
    bottomConstraint.constant = self.view.frame.height - convertedFrame.origin.y

    UIView.animate(withDuration: rate.doubleValue) {
        self.view.layoutIfNeeded()
    }
}

这在iPhone上正常工作。但是，在iPad上，它似乎可以移动两倍的高度。为什么会这样？

Answer 1

转换键盘框架时，应将nil传递给from参数。可以正确地从窗口坐标转换（如UIView convert文档中所述）。

如果您避免所有的Objective-C编码，您的代码也将更加简单。

private func keyboardWillShow(_ aNotification: Notification) {
    guard let info = aNotification.userInfo,
        let endFrame = info[UIWindow.keyboardFrameEndUserInfoKey] as? NSValue,
        let rate = info[UIWindow.keyboardAnimationDurationUserInfoKey] as? NSNumber
        else { return }

    let currentKeyboard = endFrame.cgRectValue
    let convertedFrame = self.view.convert(currentKeyboard, from: nil)
    bottomConstraint.constant = self.view.frame.height - convertedFrame.origin.y

    UIView.animate(withDuration: rate.doubleValue) {
        self.view.layoutIfNeeded()
    }
}

iPad上的键盘高度不正确

1 个答案: