我正在使用UIKeyboardFrameEndUserInfoKey
键获取键盘高度,如下所示:
let keyboardHeight = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue.height
print(keyboardHeight)
如果我点击
UITextView
,键盘就会出现并打印258.0
然后按
⌘ + k
,模拟器将连接硬件键盘,因此模拟器上的软件键盘将关闭。如果我按
⌘ + k
再次组装键盘,键盘显示通知将被调用两次并打印216.0
258.0
为什么键盘显示通知被调用两次,为什么首先使用
216.0
?更新
这是我的全部代码。
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self, selector: #selector(ViewController.keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
notificationCenter.addObserver(self, selector: #selector(ViewController.keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
let userInfo = notification.userInfo!
let keyboardHeight = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue.height
print(keyboardHeight);
}
@objc func keyboardWillHide(notification: NSNotification) {
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
如果多次按
⌘ + k
,结果将显示出来...result console image
最佳答案
不太确定如何声明observer
,但是以下代码在Xcode 8和Xcode 9 beta(iOS 11)中都可以正常工作。
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name:NSNotification.Name.UIKeyboardWillShow, object: nil)
}
@objc func keyboardWillShow(sender: NSNotification) {
let keyboardHeight = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue.height
print(keyboardHeight)
}
更新:
刚刚测试了您的代码,它就可以正常工作,您还必须拥有其他干扰它的内容。
测试后的输出:
226.0
226.0
226.0
226.0
226.0
226.0