我有一个应用，它在视图的下半部分有一个文本框。 这意味着当我在文本框中输入时，键盘会覆盖文本框。
我如何在打字时向上移动视图，这样我就可以看到我键入的内容，然后在键盘消失时将它移回原来的位置?
我到处都看了，但所有的解似乎都在Obj-C中，我还不能完全转换。
任何帮助都将不胜感激。
当前回答
我看到所有的答案都是通过键盘高度的值移动视图本身。好吧，我有一个详细的答案，这可能是有用的，如果你正在使用约束即自动布局，移动一个视图通过改变其约束值(底部或顶部约束为例)由一个预定义的值或你可以使用键盘大小值。
在这个例子中，我使用底部约束从文本字段到底部布局视图的初始值为175。
@IBOutlet weak var bottomConstraint: NSLayoutConstraint!
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);
}
func keyboardWillShow(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 260
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
func keyboardWillHide(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 175
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
其他回答
我看到所有的答案都是通过键盘高度的值移动视图本身。好吧，我有一个详细的答案，这可能是有用的，如果你正在使用约束即自动布局，移动一个视图通过改变其约束值(底部或顶部约束为例)由一个预定义的值或你可以使用键盘大小值。
在这个例子中，我使用底部约束从文本字段到底部布局视图的初始值为175。
@IBOutlet weak var bottomConstraint: NSLayoutConstraint!
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);
}
func keyboardWillShow(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 260
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
func keyboardWillHide(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 175
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
类似于@Boris的回答，但在Swift 5中:
override func viewDidLoad() {
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@IBAction func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@IBAction func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
override func viewWillAppear(animated: Bool)
{
super.viewWillAppear(animated)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
}
// MARK: - keyboard
func keyboardWillShow(notification: NSNotification)
{
if let userInfo = notification.userInfo {
if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
let contentInsets = self.tblView.contentInset as UIEdgeInsets
self.tblView.contentInset = UIEdgeInsets(top: contentInsets.top, left: contentInsets.left, bottom: keyboardSize.height, right:contentInsets.right)
// ...
} else {
// no UIKeyboardFrameBeginUserInfoKey entry in userInfo
}
} else {
// no userInfo dictionary in notification
}
}
func keyboardWillHide(notification: NSNotification)
{
let contentInsets = self.tblView.contentInset as UIEdgeInsets
self.tblView.contentInset = UIEdgeInsets(top: contentInsets.top, left: contentInsets.left, bottom: 0, right:contentInsets.right)
}
Swift 4中的Simpelst方法
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet var myTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
myTextField.resignFirstResponder()
}
func keyboardWillShow(notification: NSNotification) {
// let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey]
// print("duration",duration)
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight : Int = Int(keyboardSize.height)
print("keyboardWillShow",keyboardHeight)
if let height = UserDefaults.standard.value(forKey: "keyboardHeight") as? (Int) {
moveTextField(myTextField, moveDistance: -height as Int, moveDuration: 0.43, up: true)
}else{
UserDefaults.standard.set(keyboardHeight, forKey: "keyboardHeight")
moveTextField(myTextField, moveDistance: -keyboardHeight, moveDuration: 0.43, up: true)
}
}
}
func keyboardWillHide(notification: NSNotification){
if let height = UserDefaults.standard.value(forKey: "keyboardHeight") as? (Int) {
moveTextField(myTextField, moveDistance: -height as Int, moveDuration: 0.25, up: false)
}
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func moveTextField(_ textField: UITextField, moveDistance: Int, moveDuration: Double, up: Bool) {
let movement: CGFloat = CGFloat(up ? moveDistance : -moveDistance)
UIView.beginAnimations("animateTextField", context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(moveDuration)
self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)
UIView.commitAnimations()
}
}
你也可以上下移动只有UITextFiled而不是整个屏幕(UIView)。 用这种方法。
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil)
And
@objc func keyboardWillChange(notification: NSNotification) {
let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
let deltaY = targetFrame.origin.y - curFrame.origin.y
UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIViewKeyframeAnimationOptions(rawValue: curve), animations: {
self.textField.frame.origin.y+=deltaY
},completion: nil)
}
如果你在同一个VC中有2个或更多的文本字段，用户点击其中一个，然后点击另一个，不调用keyboardWillHide函数，视图会再向上一次，这是不必要的，因为你会有键盘，一个空格，它有键盘的高度，然后视图，使用我编辑的答案中的代码:
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)
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y -= keyboardSize.height
}
}
func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y += keyboardSize.height
}
}
为了解决这个问题，将两个函数"KeyboardWillShow/Hide"替换为:
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
if view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
if view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
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