我有 2 个文本字段都放在 ImageView 的顶部。当键盘出现时，底部的文本字段应该向上移动。当 ImageView 为空时，底部文本字段会按预期向上移动，但是当 ImageView 中存在图像时，底部文本字段不会向上移动。执行时可以在 print 语句的帮助下看到 keyboardWillShow 函数没有执行。有人可以帮忙吗？
以下是我的代码
class ViewController: UIViewController, UITextFieldDelegate,UINavigationControllerDelegate, UIImagePickerControllerDelegate {
@IBOutlet weak var actualImage: UIImageView!
@IBOutlet weak var shareButton: UIButton!
@IBOutlet weak var deleteButton: UIButton!
@IBOutlet weak var topTextField: UITextField!
@IBOutlet weak var bottomTextField: UITextField!
var activeTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
topTextField.delegate = self
bottomTextField.delegate = self
//Animations
topTextField.isHidden = true
bottomTextField.isHidden = true
shareButton.isEnabled = false
deleteButton.isEnabled = false
let center: NotificationCenter = NotificationCenter.default
center.addObserver(self, selector: #selector(keyboardDidShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
center.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
//Editing text Fields
func textFieldDidBeginEditing(_ textField: UITextField) {
activeTextField = textField
}
@objc func keyboardDidShow(notification: Notification) {
print("keyboarddidshow")
if activeTextField != nil {
let info: NSDictionary = notification.userInfo! as NSDictionary
let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let keyboardY = self.view.frame.size.height - keyboardSize.height
let textFieldY: CGFloat! = self.activeTextField.frame.origin.y
if self.view.frame.origin.y >= 0{
if textFieldY > (keyboardY - 80){
UIView.animate(withDuration: 0.25,delay:0.0,options:UIViewAnimationOptions.curveEaseIn, animations: {
self.view.frame = CGRect(x: 0, y: self.view.frame.origin.y - (textFieldY - (keyboardY - 80)), width: self.view.bounds.width, height: self.view.bounds.height)
}, completion: nil)
}
}
}
}
@objc func keyboardWillHide(notification: Notification){
print("switch field keyboard will hide")
UIView.animate(withDuration: 0.25,delay:0.0,options:UIViewAnimationOptions.curveEaseIn, animations: {
self.view.frame = CGRect(x: 0, y: 0, width: self.view.bounds.width, height: self.view.bounds.height)}, completion: nil
)
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
override func viewDidDisappear(_ animated: Bool) {
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
//share button pressed
@IBAction func sharePressed(_ sender: UIButton) {
topTextField.borderStyle = .none
topTextField.borderStyle = .none
let image: UIImage = generateMemedImage()
let shareImage = UIActivityViewController(activityItems: [image, topTextField,bottomTextField], applicationActivities: nil)
present(shareImage, animated: true, completion: nil)
}
//allow selecting image from photo library
@IBAction func selectFromGallery(_ sender: Any) {
let gallery = UIImagePickerController()
gallery.delegate = self
gallery.sourceType = .photoLibrary
present(gallery, animated: true, completion: nil)
}
@IBAction func selectFromCamera(_ sender: Any) {
let gallery = UIImagePickerController()
gallery.delegate = self
if UIImagePickerController.isSourceTypeAvailable(.camera){
gallery.sourceType = .camera
present(gallery, animated: true, completion: nil)
} else {
displayAlert(title: "Camera not available", message: "")
}
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage
actualImage.image = selectedImage
dismiss(animated: true, completion: nil)
topTextField.isHidden = false
bottomTextField.isHidden = false
shareButton.isEnabled = true
deleteButton.isEnabled = true
topTextField.text = " "
bottomTextField.text = " "
}
@IBAction func deletePressed(_ sender: Any) {
actualImage.image = nil
topTextField.isHidden = true
bottomTextField.isHidden = true
shareButton.isEnabled = false
deleteButton.isEnabled = false
topTextField.text = " "
bottomTextField.text = " "
}
//display alert
func displayAlert(title: String, message:String){
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Dismiss", style: .default, handler: nil))
present(alert, animated: true, completion: nil)
}
func generateMemedImage() -> UIImage {
// Render view to an image
UIGraphicsBeginImageContextWithOptions(CGSize(width: 375, height: 517), false, 0)
view.drawHierarchy(in: CGRect(x: 0, y: -75, width: view.bounds.size.width, height: view.bounds.size.height), afterScreenUpdates: true)
let memedImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return memedImage
}
}
最佳答案
当您显示相机或图库时，将调用 viewDidDisappear，这会删除您对通知的订阅。也许你应该像这样订阅 viewDidAppear 中的通知:
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let center: NotificationCenter = NotificationCenter.default
center.addObserver(self, selector: #selector(keyboardDidShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
center.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
关于快速移动文本字段问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49804502/