我使用Swift与iOS编程，我使用这段代码来移动UITextField，但它不起作用。我正确地调用了函数keyboardWillShow，但是文本字段没有移动。我正在使用自动布局。
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);
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self);
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
//let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
var frame = self.ChatField.frame
frame.origin.y = frame.origin.y - keyboardSize.height + 167
self.chatField.frame = frame
println("asdasd")
}
}
以下是我对Swift 2.2的解决方案:
首先注册键盘显示/隐藏通知
NSNotificationCenter.defaultCenter().addObserver(self,
selector: #selector(MessageThreadVC.keyboardWillShow(_:)),
name: UIKeyboardWillShowNotification,
object: nil)
NSNotificationCenter.defaultCenter().addObserver(self,
selector: #selector(MessageThreadVC.keyboardWillHide(_:)),
name: UIKeyboardWillHideNotification,
object: nil)
然后在与这些通知相对应的方法中，向上或向下移动主视图
func keyboardWillShow(sender: NSNotification) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y = -keyboardSize.height
}
}
func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y = 0
}
诀窍在于“keyboardWillShow”部分，每次“QuickType建议栏”被展开或折叠时，该部分都会被调用。然后我们总是设置主视图的y坐标等于键盘总高度的负值(包括或不包括“QuickType栏”部分)。
最后不要忘记删除观察者
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
Swift 5解决方案frédéric-adda:
protocol KeyboardHandler: class {
var bottomConstraint: NSLayoutConstraint! { get set }
func keyboardWillShow(_ notification: Notification)
func keyboardWillHide(_ notification: Notification)
func startObservingKeyboardChanges()
func stopObservingKeyboardChanges()
}
extension KeyboardHandler where Self: UIViewController {
func startObservingKeyboardChanges() {
// NotificationCenter observers
NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
// Deal with rotations
NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillChangeFrameNotification, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
// Deal with keyboard change (emoji, numerical, etc.)
NotificationCenter.default.addObserver(forName: UITextInputMode.currentInputModeDidChangeNotification, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillHide(notification)
}
}
func keyboardWillShow(_ notification: Notification) {
let verticalPadding: CGFloat = 20 // Padding between the bottom of the view and the top of the keyboard
guard let value = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
let keyboardHeight = value.cgRectValue.height
// Here you could have more complex rules, like checking if the textField currently selected is actually covered by the keyboard, but that's out of this scope.
self.bottomConstraint.constant = keyboardHeight + verticalPadding
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.layoutIfNeeded()
})
}
func keyboardWillHide(_ notification: Notification) {
self.bottomConstraint.constant = 0
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.layoutIfNeeded()
})
}
func stopObservingKeyboardChanges() {
NotificationCenter.default.removeObserver(self)
}
}
在任何UIViewController中:
遵循KeyboardHandler协议
extension AnyViewController: KeyboardHandler {}
为屏幕上最后一个底部元素添加底部约束。
@IBOutlet var bottomConstraint: NSLayoutConstraint!
添加观察者订阅/取消订阅:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
startObservingKeyboardChanges()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
stopObservingKeyboardChanges()
}
享受吧!
我已采取以下方式:
当textfield superview为view时，这很有用
class AdminLoginViewController: UIViewController,
UITextFieldDelegate{
@IBOutlet weak var txtUserName: UITextField!
@IBOutlet weak var txtUserPassword: UITextField!
@IBOutlet weak var btnAdminLogin: UIButton!
private var activeField : UIView?
var param:String!
var adminUser : Admin? = nil
var kbHeight: CGFloat!
override func viewDidLoad()
{
self.addKeyBoardObserver()
self.addGestureForHideKeyBoard()
}
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func addGestureForHideKeyBoard()
{
let tapGesture = UITapGestureRecognizer(target: self, action: Selector("hideKeyboard"))
tapGesture.cancelsTouchesInView = false
view.addGestureRecognizer(tapGesture)
}
func hideKeyboard() {
self.view.endEditing(true)
}
func addKeyBoardObserver(){
NSNotificationCenter.defaultCenter().addObserver(self, selector: "willChangeKeyboardFrame:",
name:UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "willChangeKeyboardFrame:",
name:UIKeyboardWillHideNotification, object: nil)
}
func removeObserver(){
NSNotificationCenter.defaultCenter().removeObserver(self)
}
//MARK:- textfiled Delegate
func textFieldShouldBeginEditing(textField: UITextField) -> Bool
{
activeField = textField
return true
}
func textFieldShouldEndEditing(textField: UITextField) -> Bool
{
if activeField == textField
{
activeField = nil
}
return true
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
if txtUserName == textField
{
txtUserPassword.becomeFirstResponder()
}
else if (textField == txtUserPassword)
{
self.btnAdminLoginAction(nil)
}
return true;
}
func willChangeKeyboardFrame(aNotification : NSNotification)
{
if self.activeField != nil && self.activeField!.isFirstResponder()
{
if let keyboardSize = (aNotification.userInfo![UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
{
let dy = (self.activeField?.superview?.convertRect((self.activeField?.frame)!, toView: view).origin.y)!
let height = (self.view.frame.size.height - keyboardSize.size.height)
if dy > height
{
var frame = self.view.frame
frame.origin.y = -((dy - height) + (self.activeField?.frame.size.height)! + 20)
self.view.frame = frame
}
}
}
else
{
var frame = self.view.frame
frame.origin.y = 0
self.view.frame = frame
}
} }
struct MoveKeyboard {
static let KEYBOARD_ANIMATION_DURATION : CGFloat = 0.3
static let MINIMUM_SCROLL_FRACTION : CGFloat = 0.2;
static let MAXIMUM_SCROLL_FRACTION : CGFloat = 0.8;
static let PORTRAIT_KEYBOARD_HEIGHT : CGFloat = 216;
static let LANDSCAPE_KEYBOARD_HEIGHT : CGFloat = 162;
}
func textFieldDidBeginEditing(textField: UITextField) {
let textFieldRect : CGRect = self.view.window!.convertRect(textField.bounds, fromView: textField)
let viewRect : CGRect = self.view.window!.convertRect(self.view.bounds, fromView: self.view)
let midline : CGFloat = textFieldRect.origin.y + 0.5 * textFieldRect.size.height
let numerator : CGFloat = midline - viewRect.origin.y - MoveKeyboard.MINIMUM_SCROLL_FRACTION * viewRect.size.height
let denominator : CGFloat = (MoveKeyboard.MAXIMUM_SCROLL_FRACTION - MoveKeyboard.MINIMUM_SCROLL_FRACTION) * viewRect.size.height
var heightFraction : CGFloat = numerator / denominator
if heightFraction < 0.0 {
heightFraction = 0.0
} else if heightFraction > 1.0 {
heightFraction = 1.0
}
let orientation : UIInterfaceOrientation = UIApplication.sharedApplication().statusBarOrientation
if (orientation == UIInterfaceOrientation.Portrait || orientation == UIInterfaceOrientation.PortraitUpsideDown) {
animateDistance = floor(MoveKeyboard.PORTRAIT_KEYBOARD_HEIGHT * heightFraction)
} else {
animateDistance = floor(MoveKeyboard.LANDSCAPE_KEYBOARD_HEIGHT * heightFraction)
}
var viewFrame : CGRect = self.view.frame
viewFrame.origin.y -= animateDistance
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(NSTimeInterval(MoveKeyboard.KEYBOARD_ANIMATION_DURATION))
self.view.frame = viewFrame
UIView.commitAnimations()
}
func textFieldDidEndEditing(textField: UITextField) {
var viewFrame : CGRect = self.view.frame
viewFrame.origin.y += animateDistance
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(NSTimeInterval(MoveKeyboard.KEYBOARD_ANIMATION_DURATION))
self.view.frame = viewFrame
UIView.commitAnimations()
}
最后，因为我们使用委托方法
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
使用objective-c重构http://www.cocoawithlove.com/2008/10/sliding-uitextfields-around-to-avoid.html
