Apple在本文档中已对您的问题进行了很好的说明。此页面上的示例代码(at Listing 4-1
)完全满足您的需求,仅当当前编辑应在键盘下时,它才会滚动视图。您只需要将所需的控件放在scrollViiew中即可。唯一的问题是,这是Objective-C,我想您需要在Swift..so ..这里:
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:例如:
self.you_text_field.delegate = self
并记住要调用registerForKeyboardNotifications
viewInit和deregisterFromKeyboardNotifications
退出。
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
}