切换UITextField（Swift）时出现键盘调整视图

Question

我有两个UIView，主要的一个和一个将在键盘出现时向上移动（第二个UIView有两个文本字段）。 我已经用下面的代码做到了：

LoginViewController.swift：

override func viewDidLoad() {
    super.viewDidLoad()


    self.originalCenter = self.contentView.center;
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardDidShow:", name: UIKeyboardDidShowNotification, object: nil)


}

func keyboardDidShow(notification: NSNotification)
{
    UIView.animateWithDuration(1.0, animations: {
    self.contentView.center = CGPointMake(self.originalCenter.x, self.originalCenter.y - 40);
     })

}

我的大问题是，由于UIView的移动取决于键盘通知，因此当用户单击一个TextField时，它会按原样向上移动，但是当用户单击第二个TextField时，视图会自动向下移动。 我在做什么错？

这是正在发生的事情： 键盘错误Gif

在这里回答了这个问题，但是我需要Swift语言的解决方案。

Answer 1

创建一个实例变量，然后检查键盘是否已激活：类ViewController：UIViewController，UITextFieldDelegate {

var _keyboardActivated: Bool = false

override func viewDidLoad() {
    super.viewDidLoad()
    registerForKeyboardNotifications()
}

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self,
        name: UIKeyboardDidShowNotification,
        object: nil)

    NSNotificationCenter.defaultCenter().removeObserver(self,
        name: UIKeyboardWillHideNotification,
        object: nil)
}

func registerForKeyboardNotifications() {
    NSNotificationCenter.defaultCenter().addObserver(
        self,
        selector: "keyboardWillShow:",
        name: UIKeyboardWillShowNotification,
        object: nil)

    NSNotificationCenter.defaultCenter().addObserver(
        self,
        selector: "keyboardWillBeHidden:",
        name: UIKeyboardWillHideNotification,
        object: nil)
}

func keyboardWillShow(notification: NSNotification) {
    if (!_keyboardActivated) {
      // do stuff
    }
    _keyboardActivated = true
}

func keyboardWillBeHidden(notification: NSNotification) {
    _keyboardActivated = false
}
}

Answer 2

设置文本字段的委托并实现以下方法

func textFieldDidBeginEditing(textField: UITextField) {
        animateViewMoving(true, moveValue: 100)
}
func textFieldDidEndEditing(textField: UITextField) {
        animateViewMoving(false, moveValue: 100)
}

func animateViewMoving (up:Bool, moveValue :CGFloat){
    var movementDuration:NSTimeInterval = 0.3
    var movement:CGFloat = ( up ? -moveValue : moveValue)
    UIView.beginAnimations( "animateView", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(movementDuration )
    self.view.frame = CGRectOffset(self.view.frame, 0,  movement)
    UIView.commitAnimations()
}

参考： http : //www.jogendra.com/2015/01/uitextfield-move-up-when-keyboard.html