在 iPad 拆分视图中处理另一个应用程序的模糊键盘（iOS 9 多任务处理）

Question

以前，如果有人在自己的应用程序上显示键盘，就会将所有内容嵌入 UIScrollView 并调整 contentInset 以防止内容被键盘遮挡。

现在在 iOS9 上使用拆分视图多任务处理，即使用户不再与其他应用交互，键盘也可能随时出现并保持可见。

问题

是否有一种简单的方法来适应所有不希望键盘可见并且不开始将所有内容嵌入滚动视图的视图控制器？

Answer 1

秘诀是收听 UIKeyboardWillChangeFrame 通知，当键盘从您的应用程序或与您的应用程序运行并排的另一个应用程序 shown/hidden 时触发。

我创建此扩展程序是为了方便 start/stop 观察这些事件（我在 viewWillAppear/Disappear 中调用它们），并轻松获得 obscuredHeight通常用来调整你的table/collection/scrollview.

的底部contentInset

@objc protocol KeyboardObserver
{
    func startObservingKeyboard() // Call this in your controller's viewWillAppear
    func stopObservingKeyboard() // Call this in your controller's viewWillDisappear
    func keyboardObscuredHeight() -> CGFloat
    @objc optional func adjustLayoutForKeyboardObscuredHeight(_ obscuredHeight: CGFloat, keyboardFrame: CGRect, keyboardWillAppearNotification: Notification) // Implement this in your controller and adjust your bottom inset accordingly
}

var _keyboardObscuredHeight:CGFloat = 0.0;

extension UIViewController: KeyboardObserver
{
    func startObservingKeyboard()
    {
        NotificationCenter.default.addObserver(self, selector: #selector(observeKeyboardWillChangeFrameNotification(_:)), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)
    }

    func stopObservingKeyboard()
    {
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)
    }

    func observeKeyboardWillChangeFrameNotification(_ notification: Notification)
    {
        guard let window = self.view.window else {
            return
        }

        let animationID = "\(self) adjustLayoutForKeyboardObscuredHeight"
        UIView.beginAnimations(animationID, context: nil)
        UIView.setAnimationCurve(UIViewAnimationCurve(rawValue: (notification.userInfo![UIKeyboardAnimationCurveUserInfoKey]! as AnyObject).intValue)!)
        UIView.setAnimationDuration((notification.userInfo![UIKeyboardAnimationCurveUserInfoKey]! as AnyObject).doubleValue)

        let keyboardFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey]! as AnyObject).cgRectValue
        _keyboardObscuredHeight = window.convert(keyboardFrame!, from: nil).intersection(window.bounds).size.height
        let observer = self as KeyboardObserver
        observer.adjustLayoutForKeyboardObscuredHeight!(_keyboardObscuredHeight, keyboardFrame: keyboardFrame!, keyboardWillAppearNotification: notification)

        UIView.commitAnimations()
    }

    func keyboardObscuredHeight() -> CGFloat
    {
        return _keyboardObscuredHeight
    }
}

在 iPad 拆分视图中处理另一个应用程序的模糊键盘（iOS 9 多任务处理）

Handle another app's obscuring keyboard on iPad split view (iOS 9 multitasking)

keyboard

multitasking

ipad

ios

splitview