如何得到键盘的高度？

在不同的 iOS 设备上，键盘的高度是不同的。有人知道如何通过编程得到设备键盘的高度吗？

143592 次浏览
小开
最佳答案

斯威夫特

您可以通过订阅 UIKeyboardWillShowNotification通知来获得键盘高度。(假设你想在显示之前知道它的高度)。

Swift 4

NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: UIResponder.keyboardWillShowNotification,
object: nil
)

@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
}
}

Swift 3

NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: NSNotification.Name.UIKeyboardWillShow,
object: nil
)

@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
}
}

Swift 2

NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)

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
}
小开

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
}
}

分机:

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
}
}

分机:

private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:))
}

小费

UIKeyboardDidShowNotification 或 UIKeyboardWillShowNotification 可能调用两次并得到不同的结果，这个 文章解释了为什么调用两次。

在 Swift 2.2中

Swift 2.2不推荐在选择器中使用字符串，而是引入了新的语法: #selector。

比如:

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
}

分机:

    private extension Selector {


static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(_:))
}
小开

简短版本:

func keyboardWillShow(notification: NSNotification) {


if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
}
}
小开

Swift 3.0和 Swift 4.1

1. 用 viewWillAppear方法登记通知:

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)
}
}
小开

//步骤1:-注册通知中心

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)
}

//步骤2:- 当键盘出现或隐藏时，这些方法将被自动调用

    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
}
小开

Swift 4和限制

在表格视图中添加相对于底部安全区域的底部约束。在我的示例中，该约束称为 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
}
小开

斯威夫特。

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)
}


}
小开

ZAFAR007为 Xcode 10中的 Swift 5更新的方法

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)
}


}
小开

Swift 5

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)")
}
}
}
小开

我必须这么做，这有点做作，不是建议。
但我觉得这很有帮助
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:
得到最大的底部约束

@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.
}

希望这能帮上忙。< br >-当键盘出现时，你的键盘将会出现 当用户点击文本域外时自动关闭和 < br >-它将把所有视图推到键盘上方。< br >-你也可以在需要的时候使用 解散键盘()

小开

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
}
小开

目标-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;
}
小开

如果让 keyboardSize = (sender.userInfo? [ UIResponder.keyboardFrameEndUserInfoKey ]作为? NSValue) ? . cgRectValue { Let keyboardHeight = keyboardSize.height 列印(键盘高度) }


提交答案