Ios 仅当键盘覆盖输入字段时才向上移动视图

你的问题在this document by Apple页已经解释得很清楚了.此页面上的示例代码(位于Listing 4-1)完全符合您的需要，它仅在当前编辑应该在键盘下时才会滚动视图.你只需要把你需要的控件放在一个滚动视图中. 唯一的问题是，这是Objective-C，我认为您在SWIFT中需要它.

声明一个变量

var activeField: UITextField?

然后添加这些方法

 func registerForKeyboardNotifications()
{
    //Adding notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWasShown:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillBeHidden:", name: UIKeyboardWillHideNotification, object: nil)
}


func deregisterFromKeyboardNotifications()
{
    //Removing notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}

func keyboardWasShown(notification: NSNotification)
{
    //Need to calculate keyboard exact size due to Apple suggestions
    self.scrollView.scrollEnabled = true
    var info : NSDictionary = notification.userInfo!
    var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height, 0.0)

    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets

    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if let activeFieldPresent = activeField
    {
        if (!CGRectContainsPoint(aRect, activeField!.frame.origin))
        {
            self.scrollView.scrollRectToVisible(activeField!.frame, animated: true)
        }
    }


}


func keyboardWillBeHidden(notification: NSNotification)
{
    //Once keyboard disappears, restore original positions
    var info : NSDictionary = notification.userInfo!
    var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, -keyboardSize!.height, 0.0)
    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
    self.view.endEditing(true)
    self.scrollView.scrollEnabled = false

}

func textFieldDidBeginEditing(textField: UITextField!)
{
    activeField = textField
}

func textFieldDidEndEditing(textField: UITextField!)
{
    activeField = nil
}

确保将ViewController声明为UITextFieldDelegate，并在初始化方法中设置正确的委托:

self.you_text_field.delegate = self

记住在viewInit上调用registerForKeyboardNotifications，在Exit上调用deregisterFromKeyboardNotifications.

编辑/更新:SWIFT 4.2语法

func registerForKeyboardNotifications(){
    //Adding notifies on keyboard appearing
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name: NSNotification.Name.UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: NSNotification.Name.UIResponder.keyboardWillHideNotification, object: nil)
}

func deregisterFromKeyboardNotifications(){
    //Removing notifies on keyboard appearing
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIResponder.keyboardWillHideNotification, object: nil)
}

@objc func keyboardWasShown(notification: NSNotification){
    //Need to calculate keyboard exact size due to Apple suggestions
    self.scrollView.isScrollEnabled = true
    var info = notification.userInfo!
    let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
    let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardSize!.height, right: 0.0)

    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets

    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if let activeField = self.activeField {
        if (!aRect.contains(activeField.frame.origin)){
            self.scrollView.scrollRectToVisible(activeField.frame, animated: true)
        }
    }
}

@objc func keyboardWillBeHidden(notification: NSNotification){
    //Once keyboard disappears, restore original positions
    var info = notification.userInfo!
    let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
    let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: -keyboardSize!.height, right: 0.0)
    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
    self.view.endEditing(true)
    self.scrollView.isScrollEnabled = false
}

func textFieldDidBeginEditing(_ textField: UITextField){
    activeField = textField
}

func textFieldDidEndEditing(_ textField: UITextField){
    activeField = nil
}