我正在尝试重新创建一个Facebook注册页面进行练习;我的viewController的设置如下:1)顶部的个人资料图像容器,2)电子邮件文字栏位3)密码文字栏位4)确认密码文本字段
为了解决键盘阻止“确认密码”字段的问题,我使用了以下侦听器。
问题是,用户第一次单击文本字段进行键入(无论是哪个文本字段)时,屏幕都将移动得太远,以至于顶部的电子邮件文本字段最终超出了顶部的屏幕大小。但是,当我关闭键盘并重新单击任何文本字段时,它会按预期方式上升:仅直到顶部文本字段到达屏幕顶部为止。
我找不到其他原因,即使重新编写了一些代码后,它仍然存在。
我的ViewController设置:
class ViewController: UIViewController {
@objc func dismissKeyboard() {
view.endEditing(true)
}
let imageContainer: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .red
return v
}()
let emailTF: UITextField = {
let tf = UITextField()
tf.translatesAutoresizingMaskIntoConstraints = false
tf.placeholder = "EMAIL"
return tf
}()
let passwordTF: UITextField = {
let tf = UITextField()
tf.translatesAutoresizingMaskIntoConstraints = false
tf.placeholder = "Password"
return tf
}()
let confirmPasswordTF: UITextField = {
let tf = UITextField()
tf.translatesAutoresizingMaskIntoConstraints = false
tf.placeholder = "Confirm password"
return tf
}()
@objc 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
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .lightGray
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
view.addSubview(imageContainer)
view.addSubview(emailTF)
view.addSubview(passwordTF)
view.addSubview(confirmPasswordTF)
NSLayoutConstraint.activate([
imageContainer.centerXAnchor.constraint(equalTo: view.centerXAnchor),
imageContainer.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.275),
imageContainer.widthAnchor.constraint(equalTo: view.heightAnchor),
imageContainer.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
emailTF.topAnchor.constraint(equalTo: imageContainer.bottomAnchor),
emailTF.heightAnchor.constraint(equalToConstant: 100),
emailTF.widthAnchor.constraint(equalToConstant: 200),
emailTF.centerXAnchor.constraint(equalTo: view.centerXAnchor),
passwordTF.topAnchor.constraint(equalTo: emailTF.bottomAnchor, constant: 20),
passwordTF.heightAnchor.constraint(equalToConstant: 100),
passwordTF.widthAnchor.constraint(equalToConstant: 200),
passwordTF.centerXAnchor.constraint(equalTo: view.centerXAnchor),
confirmPasswordTF.topAnchor.constraint(equalTo: passwordTF.bottomAnchor, constant: 20),
confirmPasswordTF.heightAnchor.constraint(equalToConstant: 100),
confirmPasswordTF.widthAnchor.constraint(equalToConstant: 200),
confirmPasswordTF.centerXAnchor.constraint(equalTo: view.centerXAnchor),
])
let tapToDismissKeyboard: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.dismissKeyboard))
view.addGestureRecognizer(tapToDismissKeyboard)
}
}
我非常感谢您为我可以采取的纠正措施提供帮助。
似乎是here和其他SO问题引起的已知问题。
要提出两点:-
1)使用UIResponder.keyboardFrameEndUserInfoKey
代替UIResponder.keyboardFrameBeginUserInfoKey
:
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
在keyboardWillShow()
中
2)这样做,您将获得键盘包括工具栏的总高度。意思是:
但是,当我关闭键盘并重新单击任何文本字段时,按预期上升:仅直到顶部文本字段达到以下位置的顶部屏幕。
这是一种越野车行为,在其中您得到不正确的高度,但不包括工具栏和:
问题是,用户第一次点击文本字段来类型(无论是哪一种),屏幕都向上移动太远,以至于顶部的电子邮件文本字段最终超出了屏幕大小顶部。
这实际上是具有实际高度的预期行为。您可以计算工具栏的高度,并从该高度中减少它以实现您的目标!如果您的VC嵌入在导航控制器中,则可以使用this
希望这会有所帮助。