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？
在Swift中：
您可以通过订阅UIKeyboardWillShowNotification通知来获得键盘高度。 （假设你想知道它显示之前的高度）。
像这样的东西：
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
)
然后你可以在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
}
1-在viewWillAppear方法中注册通知：
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
2-要求的方法：
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
print(keyboardHeight)
}
}
Swift 4和Constraints
在您的tableview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
}
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
}
}
延期：
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
}
}
延期：
private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:))
}
小费
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不赞成使用选择器的字符串，而是引入了新的语法：#selector。
就像是：
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
}
延期：
private extension Selector {
static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(_:))
}
更短的版本：
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
}
}
斯威夫特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)
}
}
//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)
}
//步骤2： - 当键盘出现或隐藏时，将自动调用这些方法
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
}