不同iOS设备上键盘的高度不同。有人知道如何以编程方式获得设备键盘的高度吗？
答案 0 :(得分：168)
在Swift中：
您可以订阅UIKeyboardWillShowNotification通知来获取键盘高度。 （假设你想知道它出现之前的高度）。
这样的事情：
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: NSNotification.Name.UIKeyboardWillShow,
object: nil
)
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: UIResponder.keyboardWillShowNotification,
object: nil
)
然后您可以在keyboardWillShow函数中访问高度，如下所示：
func keyboardWillShow(notification: NSNotification) {
let userInfo: NSDictionary = notification.userInfo!
let keyboardFrame: NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
let keyboardRectangle = keyboardFrame.CGRectValue()
let keyboardHeight = keyboardRectangle.height
}
@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
}
}
@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
}
}
答案 1 :(得分：59)
1-在viewWillAppear方法中注册通知：
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
2-要调用的方法：
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
print(keyboardHeight)
}
}
答案 2 :(得分：20)
Swift 4和Constraints
在桌面视图中添加相对于底部安全区域的底部约束。在我的例子中，约束称为tableViewBottomLayoutConstraint。
@IBOutlet weak var tableViewBottomLayoutConstraint: NSLayoutConstraint!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(notification:)), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear(notification:)), name: .UIKeyboardWillHide, object: nil)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow , object: nil)
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide , object: nil)
}
@objc
func keyboardWillAppear(notification: NSNotification?) {
guard let keyboardFrame = notification?.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else {
return
}
let keyboardHeight: CGFloat
if #available(iOS 11.0, *) {
keyboardHeight = keyboardFrame.cgRectValue.height - self.view.safeAreaInsets.bottom
} else {
keyboardHeight = keyboardFrame.cgRectValue.height
}
tableViewBottomLayoutConstraint.constant = keyboardHeight
}
@objc
func keyboardWillDisappear(notification: NSNotification?) {
tableViewBottomLayoutConstraint.constant = 0.0
}
答案 3 :(得分：16)
更新Swift 4.2
private func setUpObserver() {
NotificationCenter.default.addObserver(self, selector: .keyboardWillShow, name: UIResponder.keyboardWillShowNotification, object: nil)
}
选择器方法：
@objc fileprivate func keyboardWillShow(notification:NSNotification) {
if let keyboardRectValue = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardRectValue.height
}
}
延伸：
private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:))
}
更新Swift 3.0
private func setUpObserver() {
NotificationCenter.default.addObserver(self, selector: .keyboardWillShow, name: .UIKeyboardWillShow, object: nil)
}
选择器方法：
@objc fileprivate func keyboardWillShow(notification:NSNotification) {
if let keyboardRectValue = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardRectValue.height
}
}
延伸：
private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:))
}
提示
UIKeyboardDidShowNotification或UIKeyboardWillShowNotification可能会调用两次并得到不同的结果，这个article解释了为什么要调用两次。
在Swift 2.2中
Swift 2.2弃用了选择器的字符串，而是引入了新的语法：#selector。
类似的东西：
private func setUpObserver() {
NSNotificationCenter.defaultCenter().addObserver(self, selector: .keyboardWillShow, name: UIKeyboardWillShowNotification, object: nil)
}
选择器方法：
@objc private func keyboardWillShow(notification:NSNotification) {
let userInfo:NSDictionary = notification.userInfo!
let keyboardFrame:NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
let keyboardRectangle = keyboardFrame.CGRectValue()
let keyboardHeight = keyboardRectangle.height
editorBottomCT.constant = keyboardHeight
}
延伸：
private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(_:))
}
答案 4 :(得分：10)
此处有更短的版本：
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
}
}
答案 5 :(得分：3)
Swift 4 。
最简单的方法
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight : Int = Int(keyboardSize.height)
print("keyboardHeight",keyboardHeight)
}
}
答案 6 :(得分：2)
override func viewDidLoad() {
// Registering for keyboard notification.
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
}
/* UIKeyboardWillShowNotification. */
@objc internal func keyboardWillShow(_ notification : Notification?) -> Void {
var _kbSize:CGSize!
if let info = notification?.userInfo {
let frameEndUserInfoKey = UIResponder.keyboardFrameEndUserInfoKey
// Getting UIKeyboardSize.
if let kbFrame = info[frameEndUserInfoKey] as? CGRect {
let screenSize = UIScreen.main.bounds
//Calculating actual keyboard displayed size, keyboard frame may be different when hardware keyboard is attached (Bug ID: #469) (Bug ID: #381)
let intersectRect = kbFrame.intersection(screenSize)
if intersectRect.isNull {
_kbSize = CGSize(width: screenSize.size.width, height: 0)
} else {
_kbSize = intersectRect.size
}
print("Your Keyboard Size \(_kbSize)")
}
}
}
答案 7 :(得分：1)
//步骤1： - 注册NotificationCenter
ViewDidLoad() {
self.yourtextfield.becomefirstresponder()
// Register your Notification, To know When Key Board Appears.
NotificationCenter.default.addObserver(self, selector: #selector(SelectVendorViewController.keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
// Register your Notification, To know When Key Board Hides.
NotificationCenter.default.addObserver(self, selector: #selector(SelectVendorViewController.keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
//第2步： - 键盘出现或隐藏时会自动调用这些方法
func keyboardWillShow(notification:NSNotification) {
let userInfo:NSDictionary = notification.userInfo! as NSDictionary
let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
tblViewListData.frame.size.height = fltTblHeight-keyboardHeight
}
func keyboardWillHide(notification:NSNotification) {
tblViewListData.frame.size.height = fltTblHeight
}
答案 8 :(得分：0)
ZAFAR007的方法已针对Xcode 10中的Swift 5更新了
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight : Int = Int(keyboardSize.height)
print("keyboardHeight",keyboardHeight)
}
}
答案 9 :(得分：0)
我必须这样做。这有点黑客。不建议。
但是我发现这很有帮助
我做了扩展和结构
ViewController扩展+结构
import UIKit
struct viewGlobal{
static var bottomConstraint : NSLayoutConstraint = NSLayoutConstraint()
}
extension UIViewController{ //keyboardHandler
func hideKeyboardWhenTappedAround() {
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))
tap.cancelsTouchesInView = false
view.addGestureRecognizer(tap)
}
func listenerKeyboard(bottomConstraint: NSLayoutConstraint) {
viewGlobal.bottomConstraint = bottomConstraint
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
// Register your Notification, To know When Key Board Hides.
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}
//Dismiss Keyboard
@objc func dismissKeyboard() {
view.endEditing(true)
}
@objc func keyboardWillShow(notification:NSNotification) {
let userInfo:NSDictionary = notification.userInfo! as NSDictionary
let keyboardFrame:NSValue = userInfo.value(forKey: UIResponder.keyboardFrameEndUserInfoKey) as! NSValue
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
UIView.animate(withDuration: 0.5){
viewGlobal.bottomConstraint.constant = keyboardHeight
}
}
@objc func keyboardWillHide(notification:NSNotification) {
UIView.animate(withDuration: 0.5){
viewGlobal.bottomConstraint.constant = 0
}
}
}
用法：
得到最底层的约束
@IBOutlet weak var bottomConstraint: NSLayoutConstraint! // default 0
调用 viewDidLoad（）
中的函数override func viewDidLoad() {
super.viewDidLoad()
hideKeyboardWhenTappedAround()
listenerKeyboard(bottomConstraint: bottomConstraint)
// Do any additional setup after loading the view.
}
希望获得帮助。
-您的键盘现在将当用户在文本字段之外点击时自动关闭，并且
-它将在键盘出现时将所有视图推到键盘上方。< br />-您还可以在需要时使用 dismissKeyboard（）
答案 10 :(得分：0)
我使用以下代码，
override func viewDidLoad() {
super.viewDidLoad()
self.registerObservers()
}
func registerObservers(){
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
self.view.endEditing(true)
}
@objc func keyboardWillAppear(notification: Notification){
if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
self.view.transform = CGAffineTransform(translationX: 0, y: -keyboardHeight)
}
}
@objc func keyboardWillHide(notification: Notification){
self.view.transform = .identity
}
答案 11 :(得分：0)
Objective-C 版本：
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
然后：
- (void)keyboardWillShow:(NSNotification *)notification
{
CGFloat height = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
}