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")
}
}
如果视图上有多个文本字段，那么我建议您查看这个方法。当在字段之间切换时，你不会有视图跑开的问题，它会简单地适应所需的文本字段。它在swift 5中工作
override func viewDidLoad() {
super.viewDidLoad()
registerForKeyboardNotification()
}
扩展中的所有方法
extension StartViewController: UITextFieldDelegate {
func registerForKeyboardNotification() {
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)
}
@objc func keyboardWillShow(sender: NSNotification) {
guard let userInfo = sender.userInfo,
let keyboardFrame = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue,
let currentTextField = UIResponder.currentFirst() as? UITextField else { return }
let keyboardTopY = keyboardFrame.cgRectValue.origin.y
let convertedTextFieldFrame = view.convert(currentTextField.frame, from: currentTextField.superview)
let textFieldBottomY = convertedTextFieldFrame.origin.y + convertedTextFieldFrame.size.height
if textFieldBottomY > keyboardTopY {
let textBoxY = convertedTextFieldFrame.origin.y
let newFrameY = (textBoxY - keyboardTopY / 2) * -1
view.frame.origin.y = newFrameY
}
}
@objc func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y = 0
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
switch textField {
case emailTextField :
passwordTextField.becomeFirstResponder()
default:
emailTextField.becomeFirstResponder()
}
return true
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches , with:event)
view.endEditing(true)
}
}
最后我们用UIResponder建立方法
extension UIResponder {
private struct Static {
static weak var responder: UIResponder?
}
static func currentFirst() -> UIResponder? {
Static.responder = nil
UIApplication.shared.sendAction(#selector(UIResponder._trap), to: nil, from: nil, for: nil)
return Static.responder
}
@objc private func _trap() {
Static.responder = self
}
}
如果你正在使用自动布局，我假设你已经设置了底部空间为Superview约束。如果是这种情况，您只需更新约束的值。这是你如何用一点动画来做到这一点。
func keyboardWasShown(notification: NSNotification) {
let info = notification.userInfo!
let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.bottomConstraint.constant = keyboardFrame.size.height + 20
})
}
添加硬编码的20只是为了将文本框弹出到键盘上方一点。否则键盘的上边距和文本框的下边距将会接触。
当键盘关闭时，将约束的值重置为原始值。
func registerForKeyboardNotifications(){
//Keyboard
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWasShown), name: UIKeyboardDidShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillBeHidden), name: UIKeyboardDidHideNotification, object: nil)
}
func deregisterFromKeyboardNotifications(){
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}
func keyboardWasShown(notification: NSNotification){
let userInfo: NSDictionary = notification.userInfo!
let keyboardInfoFrame = userInfo.objectForKey(UIKeyboardFrameEndUserInfoKey)?.CGRectValue()
let windowFrame:CGRect = (UIApplication.sharedApplication().keyWindow!.convertRect(self.view.frame, fromView:self.view))
let keyboardFrame = CGRectIntersection(windowFrame, keyboardInfoFrame!)
let coveredFrame = UIApplication.sharedApplication().keyWindow!.convertRect(keyboardFrame, toView:self.view)
let contentInsets = UIEdgeInsetsMake(0, 0, (coveredFrame.size.height), 0.0)
self.scrollViewInAddCase .contentInset = contentInsets;
self.scrollViewInAddCase.scrollIndicatorInsets = contentInsets;
self.scrollViewInAddCase.contentSize = CGSizeMake((self.scrollViewInAddCase.contentSize.width), (self.scrollViewInAddCase.contentSize.height))
}
/**
this method will fire when keyboard was hidden
- parameter notification: contains keyboard details
*/
func keyboardWillBeHidden (notification: NSNotification) {
self.scrollViewInAddCase.contentInset = UIEdgeInsetsZero
self.scrollViewInAddCase.scrollIndicatorInsets = UIEdgeInsetsZero
}
在现有的答案上有一些改进。
首先，uikeyboardwillchangeframeotification可能是最好的通知，因为它处理的变化不仅仅是显示/隐藏，而是由于键盘变化(语言，使用第三方键盘等)和旋转(但注意下面的评论表明键盘将隐藏也应该处理以支持硬件键盘连接)。
其次，动画参数可以从通知中提取，以确保动画正确地组合在一起。
可能有一些选项可以进一步清理此代码，特别是如果您对强制展开字典代码感到满意的话。
class MyViewController: UIViewController {
// This constraint ties an element at zero points from the bottom layout guide
@IBOutlet var keyboardHeightLayoutConstraint: NSLayoutConstraint?
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self,
selector: #selector(self.keyboardNotification(notification:)),
name: UIResponder.keyboardWillChangeFrameNotification,
object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
@objc func keyboardNotification(notification: NSNotification) {
guard let userInfo = notification.userInfo else { return }
let endFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let endFrameY = endFrame?.origin.y ?? 0
let duration:TimeInterval = (userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey] 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.keyboardHeightLayoutConstraint?.constant = 0.0
} else {
self.keyboardHeightLayoutConstraint?.constant = endFrame?.size.height ?? 0.0
}
UIView.animate(
withDuration: duration,
delay: TimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
如果视图上有多个文本字段，那么我建议您查看这个方法。当在字段之间切换时，你不会有视图跑开的问题，它会简单地适应所需的文本字段。它在swift 5中工作
override func viewDidLoad() {
super.viewDidLoad()
registerForKeyboardNotification()
}
扩展中的所有方法
extension StartViewController: UITextFieldDelegate {
func registerForKeyboardNotification() {
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)
}
@objc func keyboardWillShow(sender: NSNotification) {
guard let userInfo = sender.userInfo,
let keyboardFrame = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue,
let currentTextField = UIResponder.currentFirst() as? UITextField else { return }
let keyboardTopY = keyboardFrame.cgRectValue.origin.y
let convertedTextFieldFrame = view.convert(currentTextField.frame, from: currentTextField.superview)
let textFieldBottomY = convertedTextFieldFrame.origin.y + convertedTextFieldFrame.size.height
if textFieldBottomY > keyboardTopY {
let textBoxY = convertedTextFieldFrame.origin.y
let newFrameY = (textBoxY - keyboardTopY / 2) * -1
view.frame.origin.y = newFrameY
}
}
@objc func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y = 0
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
switch textField {
case emailTextField :
passwordTextField.becomeFirstResponder()
default:
emailTextField.becomeFirstResponder()
}
return true
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches , with:event)
view.endEditing(true)
}
}
最后我们用UIResponder建立方法
extension UIResponder {
private struct Static {
static weak var responder: UIResponder?
}
static func currentFirst() -> UIResponder? {
Static.responder = nil
UIApplication.shared.sendAction(#selector(UIResponder._trap), to: nil, from: nil, for: nil)
return Static.responder
}
@objc private func _trap() {
Static.responder = 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!
