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")
}
}
我的做法如下:
class SignInController: UIViewController , UITextFieldDelegate {
@IBOutlet weak var scrollView: UIScrollView!
// outlet declartion
@IBOutlet weak var signInTextView: UITextField!
var kbHeight: CGFloat!
/**
*
* @method viewDidLoad
*
*/
override func viewDidLoad() {
super.viewDidLoad()
self.signInTextView.delegate = self
}// end viewDidLoad
/**
*
* @method viewWillAppear
*
*/
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
}// end viewWillAppear
/**
*
* @method viewDidAppear
*
*/
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
}// end viewDidAppear
/**
*
* @method viewWillDisappear
*
*/
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
NSNotificationCenter.defaultCenter().removeObserver(self)
}
/**
*
* @method textFieldShouldReturn
* retun the keyboard value
*
*/
// MARK -
func textFieldShouldReturn(textField: UITextField) -> Bool {
signInTextView.resignFirstResponder()
return true;
}// end textFieldShouldReturn
// MARK - keyboardWillShow
func keyboardWillShow(notification: NSNotification) {
if let userInfo = notification.userInfo {
if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
kbHeight = keyboardSize.height
self.animateTextField(true)
}
}
}// end keyboardWillShow
// MARK - keyboardWillHide
func keyboardWillHide(notification: NSNotification) {
self.animateTextField(false)
}// end keyboardWillHide
// MARK - animateTextField
func animateTextField(up: Bool) {
var movement = (up ? -kbHeight : kbHeight)
UIView.animateWithDuration(0.3, animations: {
self.view.frame = CGRectOffset(self.view.frame, 0, movement)
})
}// end animateTextField
/**
*
* @method didReceiveMemoryWarning
*
*/
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}// end didReceiveMemoryWarning
}// end SignInController
一个简单的解决方案是移动视图与键盘高度常数。
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);
}
@objc func keyboardWillShow(sender: NSNotification) {
self.view.frame.origin.y = -150 // Move view 150 points upward
}
@objc func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y = 0 // Move view to original position
}
斯威夫特5:
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(sender:)), name: UIResponder.keyboardWillShowNotification, object: nil);
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(sender:)), name: UIResponder.keyboardWillHideNotification, object: nil);
下面是一个简单的解决方案，其中文本字段有一个约束将其绑定到底部布局指南。它只是将键盘高度添加到约束常数中。
// This constraint ties the text field to the bottom layout guide
@IBOutlet var textFieldToBottomLayoutGuideConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name:UIKeyboardWillShowNotification, object: nil);
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name:UIKeyboardWillHideNotification, object: nil);
}
func keyboardWillShow(sender: NSNotification) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.textFieldToBottomLayoutGuideConstraint?.constant += keyboardSize.height
}
}
func keyboardWillHide(sender: NSNotification) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.textFieldToBottomLayoutGuideConstraint?.constant -= keyboardSize.height
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWillShow(_ notification:Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0)
}
}
func keyboardWillHide(_ notification:Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
}
}
对于任何不使用故事板设置布局约束的人。这是一种纯粹的编程方式，让它在Swift 5上工作:
在viewController中定义一个空约束。在这种情况下，我正在构建一个聊天应用程序，在屏幕的最底部有一个包含文本视图的UIView。
var discussionsMessageBoxBottomAnchor: NSLayoutConstraint = NSLayoutConstraint()
在viewDidLoad中为最底部的视图添加约束。在本例中是discussionsMessageBox。另外，为键盘事件添加监听器。
为了正确地初始化约束，您需要首先添加子视图，然后定义约束。
NotificationCenter.default.addObserver(self,
selector: #selector(self.keyboardNotification(notification:)),
name: NSNotification.Name.UIKeyboardWillChangeFrame,
object: nil)
view.addSubview(discussionsMessageBox)
if #available(iOS 11.0, *) {
discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0)
} else {
// Fallback on earlier versions
discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
}
NSLayoutConstraint.activate([ discussionsMessageBoxBottomAnchor ])
定义deinit。
deinit {
NotificationCenter.default.removeObserver(self)
}
接下来添加@JosephLord定义的代码，并对偏移量进行修正。
extension DiscussionsViewController {
@objc func keyboardNotification(notification: NSNotification) {
guard let userInfo = notification.userInfo else { return }
let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let endFrameY = endFrame?.origin.y ?? 0
let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions.curveEaseInOut.rawValue
let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)
if endFrameY >= UIScreen.main.bounds.size.height {
self.discussionsMessageBoxBottomAnchor.constant = 0.0
} else {
//Changed line
self.discussionsMessageBoxBottomAnchor.constant = -1 * (endFrame?.size.height ?? 0.0)
}
UIView.animate(
withDuration: duration,
delay: TimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
我的做法如下:
class SignInController: UIViewController , UITextFieldDelegate {
@IBOutlet weak var scrollView: UIScrollView!
// outlet declartion
@IBOutlet weak var signInTextView: UITextField!
var kbHeight: CGFloat!
/**
*
* @method viewDidLoad
*
*/
override func viewDidLoad() {
super.viewDidLoad()
self.signInTextView.delegate = self
}// end viewDidLoad
/**
*
* @method viewWillAppear
*
*/
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
}// end viewWillAppear
/**
*
* @method viewDidAppear
*
*/
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
}// end viewDidAppear
/**
*
* @method viewWillDisappear
*
*/
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
NSNotificationCenter.defaultCenter().removeObserver(self)
}
/**
*
* @method textFieldShouldReturn
* retun the keyboard value
*
*/
// MARK -
func textFieldShouldReturn(textField: UITextField) -> Bool {
signInTextView.resignFirstResponder()
return true;
}// end textFieldShouldReturn
// MARK - keyboardWillShow
func keyboardWillShow(notification: NSNotification) {
if let userInfo = notification.userInfo {
if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
kbHeight = keyboardSize.height
self.animateTextField(true)
}
}
}// end keyboardWillShow
// MARK - keyboardWillHide
func keyboardWillHide(notification: NSNotification) {
self.animateTextField(false)
}// end keyboardWillHide
// MARK - animateTextField
func animateTextField(up: Bool) {
var movement = (up ? -kbHeight : kbHeight)
UIView.animateWithDuration(0.3, animations: {
self.view.frame = CGRectOffset(self.view.frame, 0, movement)
})
}// end animateTextField
/**
*
* @method didReceiveMemoryWarning
*
*/
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}// end didReceiveMemoryWarning
}// end SignInController
