问题描述
新手很快，我确实已经花了4天的时间，并且坚持这一工作，我认为这很简单，对我来说再没有意义了。 当我使用情节提要创建UItextfiled时，来回UItextfield.text
并没有问题。当像在“ textProjectNumber”下面的示例那样以编程方式创建UItextfiled.text时 那么即使我在urtextfiled中输入了项目编号，并尝试稍后在同一个类中调用该文本，似乎该文本是= nil...。请您帮我了解问题出在哪里。 / p>
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let textProjectNumber = UITextField(frame: CGRect(x: 20,y: 100,width: 300,height: 40))
textProjectNumber.translatesAutoresizingMaskIntoConstraints = false
textProjectNumber.placeholder = "Enter text here"
textProjectNumber.font = UIFont.systemFont(ofSize: 15)
textProjectNumber.borderStyle = UITextField.BorderStyle.roundedRect
textProjectNumber.autocorrectionType = UITextAutocorrectionType.no
textProjectNumber.keyboardType = UIKeyboardType.numberPad
textProjectNumber.returnKeyType = UIReturnKeyType.done
textProjectNumber.clearButtonMode = UITextField.ViewMode.whileEditing
textProjectNumber.contentVerticalAlignment = UIControl.ContentVerticalAlignment.center
textProjectNumber.tag = 1
textProjectNumber.updateConstraintsIfNeeded()
textProjectNumber.delegate = self
// add the uitextfield in the view
self.view.addSubview(textProjectNumber)
//add the constrain for this uitextfield
NSLayoutConstraint.activate([
textProjectNumber.centerXAnchor.constraint(
equalTo: view.centerXAnchor,constant: 0),textProjectNumber.centerYAnchor.constraint(
equalTo: view.centerYAnchor,constant: 0)
])
textProjectName.translatesAutoresizingMaskIntoConstraints = false
textProjectName.delegate = self
// MARK: - Navigation
// Enable the Save button only if the text field has a valid project name.
updateSaveButtonState()
}
//MARK: UItextFieldDelegate
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.autocorrectionType = .no
if textField.tag == 2 { // tag 2 = textProjectName tag1 = textProjNumber
textField.autocorrectionType = .yes
}
textField.autocorrectionType = .no
//Hide the keyboard
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(_ textField: UITextField) {
//update the status of the buttong when we finish editing the uI textfiled
updateSaveButtonState()
//add the title of this new project creation with textfiled + PF-
if textProjectName.text?.isEmpty ?? true {
navigationItem.title = "PF-" + textProjectName.text! }
textField.autocorrectionType = .no
textField.resignFirstResponder()
}
func textFieldDidBeginEditing(_ textField: UITextField) {
// Disable the Save button while editing.
saveNewProjectButton.isEnabled = false
createbuttonsinkeyboard(textField)
if textField.tag == 2 {
textField.autocorrectionType = .yes
} else {
textField.autocorrectionType = .no
}
}
func textField(_ textField: UITextField,shouldChangeCharactersIn range: NSRange,replacementString string: String) -> Bool {
if textField.tag == 1 {
if range.length + range.location > (textField.text?.count)! {
return false
}
let newLenght = (textField.text?.count)! + string.count - range.length
if (textField.text?.contains("PF-"))! {
textField.text! = textField.text!.replacingOccurrences(of: "PF-",with: "",options: NSString.CompareOptions.literal,range: nil)
}
print("do i do that")
return newLenght <= 8
}
return true
}
//MARK: Private Methods
private func updateSaveButtonState(){
// Disable the Save button if the text field is empty.
if textProjectName.text?.isEmpty ?? false || ((textProjectName.text?.isEmpty) != false) {
saveNewProjectButton.isEnabled = false
} else {
saveNewProjectButton.isEnabled = true
}
}
//MARK: Create object function with keyboard
@objc func Done(){
view.endEditing(true)
let numbFromUser = textProjectNumber.text
if activeTextField.tag == 1 {
textProjectNumber.text = "PF-" + numbFromUser!
}
print(numbFromUser!)
}
@objc func Cancel(){
self.activeTextField.text = ""
}
//save button function
@IBAction func SaveNewProject() {
let actionSheet = UIAlertController (title: "WARNING",message: "CREAT A NEW PROJECT WITH THE FOLLOWING INFO:\n\(textProjectNumber.text ?? "Empty") \n\(textProjectNumber.text ?? "Empty")",preferredStyle: .alert)
let okaction = UIAlertAction(title: "Agree",style: .default) { (action) in
self.gotoFouthViewController(/*add argument if needed*/)
}
//cancel the alert
let cancelaction = UIAlertAction(title: "Cancel",style: .cancel) { (action) in
}
actionSheet.addAction(okaction)
actionSheet.addAction(cancelaction)
present(actionSheet,animated: true,completion: nil)
}
func gotoFouthViewController() {
//push or present the fourth view controller here
let home = storyboard?.instantiateViewController(withIdentifier: "homepage") as! ViewController
// secondVC.statusDelegate = self
navigationController?.pushViewController(home,animated: true)
}
func createbuttonsinkeyboard(_ textField: UITextField) {
// self.activeTextField.text is an optional,we safely unwrap it here
self.activeTextField = textField
// // Create a toolbar
let toolBar = UIToolbar(frame: CGRect(x: 0,y: 0,width: UIScreen.main.bounds.width,height: 40))
//toolBar.sizeToFit()
let doneButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.done,target: self,action: #selector(Done))
let spaceButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.flexibleSpace,action: nil)
let emptyButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.cancel,action: #selector(Cancel))
// Add a toolbar buttons in each textfiled
textField.inputAccessoryView = toolBar
toolBar.setItems([emptyButton,spaceButton,doneButton],animated: false)
toolBar.updateConstraintsIfNeeded()
return;
}
}
this help me to fid constraint auto or not
extension NSLayoutConstraint {
override public var description: String {
let id = identifier ?? ""
return "id: \(id),constant: \(constant)" //you may print whatever you want here
}
}
解决方法
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