动态获取键盘框架答案

【问题标题】：Get the frame of the keyboard dynamically动态获取键盘框架
【发布时间】：2012-08-12 22:17:48
【问题描述】：

是否可以动态获取键盘的框架，实际上是它的高度？因为我有一个UITextView，当键盘的输入法改变时，我想根据键盘框架的高度来调整它的高度。如您所知，不同的输入法可能有不同的键盘框架高度。

【问题讨论】：

【解决方案1】：

试试这个：

[[NSNotificationCenter defaultCenter] addObserver:self
                                     selector:@selector(keyboardWasShown:)
                                         name:UIKeyboardDidShowNotification
                                       object:nil];

- (void)keyboardWasShown:(NSNotification *)notification
{

// Get the size of the keyboard.
CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

//Given size may not account for screen rotation
int height = MIN(keyboardSize.height,keyboardSize.width);
int width = MAX(keyboardSize.height,keyboardSize.width);

//your other code here..........
}

Tutorial for more information

【讨论】：

这在 iOS8 中使用不同高度/类型的键盘时特别有用。到目前为止，只需硬编码 216（纵向）就可以了。谢谢。
对于 swift 用户：使用let keyboardSize = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue().size
@LoïsDiQual 谢谢
你应该改用UIKeyboardFrameEndUserInfoKey。我不认为这对UIKeyboardDidShowNotification 很重要，但是如果你把它改成UIKeyboardWillShowNotification 你会得到一些奇怪的错误，因为框架将是之前的状态，而不是之后的状态。
更好的方法是使用可选链接： if let keyboardSize: CGSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as?NSValue)?.cgRectValue.size { print("Keyboard size: (keyboardSize )") }

【解决方案2】：

只要按照 Apple 的这个教程，你就会得到你想要的。 Apple Documentation。确定键盘覆盖区域请参考tutorial。

【讨论】：

但是我如何检测到输入法更改动作呢？
如果您是程序员，那么您应该知道在任何给定时间您打开了哪个输入软键盘。
我希望我知道，但我不能。如果您知道如何检测输入法更改动作并获取当前键盘的高度，请告诉我。我真的很感激:)
获取输入字符是textField:shouldChangeCharactersInRange。我在输入美元金额时使用它，我不希望使用除小数以外的任何东西
您应该提供一些代码作为示例，因为链接失效的那一天，答案就没有用了。

【解决方案3】：

对于 Swift 3 用户，@Hector 代码（有一些补充）将是：

在您的viewDidLoad 中添加观察者：

NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardDidShow(_:)), name: .UIKeyboardDidShow , object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardDidHide(_:)), name: .UIKeyboardDidHide , object: nil)

然后实现这些方法：

func keyboardDidShow(_ notification: NSNotification) {
     print("Keyboard will show!")
     // print(notification.userInfo)

     let keyboardSize:CGSize = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue.size
     print("Keyboard size: \(keyboardSize)")  

     let height = min(keyboardSize.height, keyboardSize.width)
     let width = max(keyboardSize.height, keyboardSize.width)

}

func keyboardDidHide(_ notification: NSNotification) {
        print("Keyboard will hide!")
}

【讨论】：

【解决方案4】：

您可以将此代码添加到包含 Swift 3 中的文本字段的视图中。这将使文本字段随着键盘上下动画。

private var keyboardIsVisible = false
private var keyboardHeight: CGFloat = 0.0

// MARK: Notifications

private func registerForKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
private func deregisterFromKeyboardNotifications() {
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

// MARK: Triggered Functions

@objc private func keyboardWillShow(notification: NSNotification) {
    keyboardIsVisible = true
    guard let userInfo = notification.userInfo else {
        return
    }
    if let keyboardHeight = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.height {
        self.keyboardHeight = keyboardHeight
    }
    if !textField.isHidden {
        if let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber,
            let curve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber {
            animateHUDWith(duration: duration.doubleValue,
                           curve: UIViewAnimationCurve(rawValue: curve.intValue) ?? UIViewAnimationCurve.easeInOut,
                           toLocation: calculateTextFieldCenter())
        }
    }
}

@objc private func keyboardWillBeHidden(notification: NSNotification) {
    keyboardIsVisible = false
    if !self.isHidden {
        guard let userInfo = notification.userInfo else {
            return
        }
        if let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber,
            let curve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber {
            animateHUDWith(duration: duration.doubleValue,
                           curve: UIViewAnimationCurve(rawValue: curve.intValue) ?? UIViewAnimationCurve.easeInOut,
                           toLocation: calculateTextFieldCenter())
        }
    }
}

// MARK: - Helpers

private func animateHUDWith(duration: Double, curve: UIViewAnimationCurve, toLocation location: CGPoint) {
    UIView.beginAnimations(nil, context: nil)
    UIView.setAnimationDuration(TimeInterval(duration))
    UIView.setAnimationCurve(curve)
    textField.center = location
    UIView.commitAnimations()
}

private func calculateTextFieldCenter() -> CGPoint {
    if !keyboardIsVisible {
        return self.center
    } else {
        let yLocation = (self.view.frame.height - keyboardHeight) / 2
        return CGPoint(x: self.center.x, y: yLocation)
    }
}

【讨论】：