ios - 优雅地将 UIView 移动到键盘的 inputAccessoryView

Question

是否有一种优雅的方式可以将位于其父视图底部的UIView（即 a ）无缝移动到键盘的？UIButtoninputAccessoryView

我设想键盘基本上是在滑入时拿起按钮并将其向上拖动。请参阅下面的模型。显然，我希望这也能反过来工作。

我知道如何分别做，但我不知道如何结合起来。有谁以前这样做过吗？

谢谢！

更新：我忘了提到我主要在UIScrollViews. 虽然下面安德烈的答案适用于普通视图，但在将其与滚动视图一起使用时会中断。

Answer 1

在这种情况下，您可以忽略使用 inputaccessoryview，而是调整登录按钮对键盘通知的底部约束。

class ViewController: UIViewController {
  @IBOutlet weak var signInButtonBottomConstraint: NSLayoutConstraint!

  override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
  }

  func keyboardWillShow(notification: NSNotification) {
    let userInfo = notification.userInfo!

    let animationDuration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as! Double
    let keyboardEndFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()

    signInButtonBottomConstraint.constant = keyboardEndFrame.height
    UIView.animateWithDuration(animationDuration) { () -> Void in
      self.view.layoutIfNeeded()
    }
  }

  func keyboardWillHide(notification: NSNotification) {
    let userInfo = notification.userInfo!

    let animationDuration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as! Double

    signInButtonBottomConstraint.constant = 0.0
    UIView.animateWithDuration(animationDuration) { () -> Void in
      self.view.layoutIfNeeded()
    }
  }
}