UITextField 无法以编程方式使用添加约束
UITextField not working with add constraints programmatically
这是我的代码，我在滚动视图中以编程方式添加 UITextfield。但是 UITextField 无法打开键盘。
看起来 UITextField 甚至没有启用添加的用户交互启用 true。
我只使用约束，没有故事板，没有 xibs。只能通过编程方式约束。
下面是我的代码：
class SignupViewController : UIViewController {
var backButton : UIButton!
var titleLabel : UILabel!
var navBarView : UIView!
var scrollView : UIScrollView!
var scrollMainView : UIView!
var emailfieldView : UIView!
var emailTextField : UITextField = UITextField() override func viewDidLoad() {
super.viewDidLoad()
setDesign()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
}func setDesign(){
setNavegationBar()
setBackgroundImage()
addScrollView()
}
func setBackgroundImage(){
let backgroundImage = UIImageView(image: UIImage(named: "loginbg.png"))
self.view.addSubview(backgroundImage)
backgroundImage.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = backgroundImage.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = backgroundImage.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = backgroundImage.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 0)
let bottomConst = backgroundImage.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([leadingConst,trailingConst,topConst,bottomConst])
}
func setNavegationBar(){
navigationItem.title = "Join"
view.backgroundColor = UIColor.white
navigationController?.navigationBar.isHidden = true
navigationController?.navigationBar.tintColor = UIColor.white
navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
setNavBarView()
}
func setNavBarView(){
navBarView = UIView()
self.view.addSubview(navBarView)
navBarView.translatesAutoresizingMaskIntoConstraints = false
let guide = view.safeAreaLayoutGuide
let heightCost = navBarView.heightAnchor.constraint(equalToConstant: 64.0)
let leadingCost = navBarView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0.0)
let trailingConst = navBarView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topCost = navBarView.topAnchor.constraint(equalTo: guide.topAnchor, constant: 0.0)
NSLayoutConstraint.activate([trailingConst,heightCost,topCost,leadingCost])
setBackButton()
setNavTitle()
}
func setBackButton(){
backButton = UIButton(type: UIButtonType.custom)
backButton.setImage(UIImage(named: "join_back"), for: UIControlState.normal)
navBarView.addSubview(backButton)
backButton.translatesAutoresizingMaskIntoConstraints = false
let widthCost = backButton.widthAnchor.constraint(equalToConstant: 44.0)
let heightCost = backButton.heightAnchor.constraint(equalToConstant: 44.0)
let leadingCost = backButton.leadingAnchor.constraint(equalTo: navBarView.leadingAnchor, constant: 0.0)
let topCost = backButton.topAnchor.constraint(equalTo: navBarView.topAnchor, constant: 0.0)
NSLayoutConstraint.activate([widthCost,heightCost,topCost,leadingCost])
backButton.addTarget(self, action: #selector(self.backButtonPress), for: UIControlEvents.touchUpInside)
}
func setNavTitle(){
titleLabel = UILabel()
titleLabel.text = "Join Dubai Store"
titleLabel.font = UIFont(name: "Dubai-Regular", size: 22.0)
titleLabel.textAlignment = NSTextAlignment.center
titleLabel.tintColor = UIColor(hexString: "#353535")
navBarView.addSubview(titleLabel)
titleLabel.translatesAutoresizingMaskIntoConstraints = false
let heightCost = titleLabel.heightAnchor.constraint(equalToConstant: 44.0)
let topCost = titleLabel.topAnchor.constraint(equalTo: navBarView.topAnchor, constant: 0.0)
let centerCost = titleLabel.centerXAnchor.constraint(equalTo: navBarView.centerXAnchor)
NSLayoutConstraint.activate([heightCost,topCost,centerCost])
}
@objc func backButtonPress(){
self.view.endEditing(true)
self.dismissView()
}
func addScrollView(){
scrollView = UIScrollView()
view.addSubview(scrollView)
scrollView.layer.borderWidth = 1.0
scrollView.layer.borderColor = UIColor.red.cgColor
scrollView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollView.topAnchor.constraint(equalTo: navBarView.bottomAnchor, constant: 0)
let bottomConst = scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([leadingConst,trailingConst,topConst,bottomConst])
addScrollMainView()
}
func addScrollMainView() {
scrollMainView = UIView()
scrollView.addSubview(scrollMainView)
scrollMainView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollMainView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 0)
let trailingConst = scrollMainView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollMainView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0)
let bottomConst = scrollMainView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([topConst,leadingConst,trailingConst,bottomConst])
emailFieldView()
}
func emailFieldView(){
emailfieldView = UIView()
emailfieldView.isUserInteractionEnabled = true
emailfieldView.translatesAutoresizingMaskIntoConstraints = false
scrollMainView.addSubview(emailfieldView)
let topCost = emailfieldView.topAnchor.constraint(equalTo: scrollMainView.topAnchor, constant: 0.0)
let leadingConst = emailfieldView.leadingAnchor.constraint(equalTo: scrollMainView.leadingAnchor, constant: 0)
let trailingConst = emailfieldView.trailingAnchor.constraint(equalTo: scrollMainView.trailingAnchor, constant: 0)
let heightCost = emailfieldView.heightAnchor.constraint(equalToConstant: 62.0)
NSLayoutConstraint.activate([trailingConst,heightCost,topCost,leadingConst])
//emailTextField = UITextField(frame: CGRect(x: 10, y: 0, width: SCREEN_WIDTH, height: 50))
emailTextField.placeholder = "Email"
emailTextField.layer.borderColor = UIColor.red.cgColor
emailTextField.layer.borderWidth = 1.0
// emailTextField.font = UIFont.systemFont(ofSize: 15)
// emailTextField.borderStyle = UITextBorderStyle.none
// emailTextField.keyboardType = UIKeyboardType.default
// emailTextField.returnKeyType = UIReturnKeyType.done
// //emailTextField.clearButtonMode = UITextFieldViewMode.whileEditing
emailTextField.isUserInteractionEnabled = true
emailTextField.allowsEditingTextAttributes = true
//emailTextField.contentVerticalAlignment = UIControlContentVerticalAlignment.center
emailTextField.addTarget(self, action: #selector(self.textFieldShouldBeginEditing), for: UIControlEvents.touchUpInside)
emailfieldView.addSubview(emailTextField)
emailTextField.translatesAutoresizingMaskIntoConstraints = false
emailTextField.contentMode = UIViewContentMode.left
emailTextField.delegate = self
let etopCost = emailTextField.topAnchor.constraint(equalTo: emailfieldView.topAnchor, constant: 0.0)
let eleadingConst = emailTextField.leadingAnchor.constraint(equalTo: emailfieldView.leadingAnchor, constant: 10)
let etrailingConst = emailTextField.trailingAnchor.constraint(equalTo: emailfieldView.trailingAnchor, constant: -10)
let eheightCost = emailTextField.heightAnchor.constraint(equalToConstant: 50.0)
NSLayoutConstraint.activate([etopCost,eleadingConst,etrailingConst,eheightCost])
self.scrollMainView.bringSubview(toFront: emailTextField)
emailTextField.isAccessibilityElement = true
} }
extension SignupViewController: UITextFieldDelegate {
func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
// return NO to disallow editing.
print("TextField should begin editing method called")
return true
}
func textFieldDidBeginEditing(_ textField: UITextField) {
// became first responder
print("TextField did begin editing method called")
}
func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
// return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
print("TextField should snd editing method called")
return true
}
func textFieldDidEndEditing(_ textField: UITextField) {
// may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called
print("TextField did end editing method called")
}
func textFieldDidEndEditing(_ textField: UITextField, reason: UITextFieldDidEndEditingReason) {
// if implemented, called in place of textFieldDidEndEditing:
print("TextField did end editing with reason method called")
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// return NO to not change text
print("While entering the characters this method gets called")
return true
}
func textFieldShouldClear(_ textField: UITextField) -> Bool {
// called when clear button pressed. return NO to ignore (no notifications)
print("TextField should clear method called")
return true
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
// called when 'return' key pressed. return NO to ignore.
print("TextField should return method called")
// may be useful: textField.resignFirstResponder()
return true
}
}
我只是 运行 你的代码，看起来 scrollMainView 在视图的层次结构中不可见。只需更改约束即可。这是代码：
func addScrollMainView() {
scrollMainView = UIView()
scrollView.addSubview(scrollMainView)
scrollMainView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollMainView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = scrollMainView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollMainView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0)
let bottomConst = scrollMainView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([topConst,leadingConst,trailingConst,bottomConst])
emailFieldView()
}
顺便说一句，这与你的问题无关，但最好在一开始就创建bg。只需使用以下代码：
func setDesign(){
setBackgroundImage()
setNavegationBar()
addScrollView()
}
这是我的代码，我在滚动视图中以编程方式添加 UITextfield。但是 UITextField 无法打开键盘。 看起来 UITextField 甚至没有启用添加的用户交互启用 true。 我只使用约束，没有故事板，没有 xibs。只能通过编程方式约束。 下面是我的代码：
class SignupViewController : UIViewController {
var backButton : UIButton!
var titleLabel : UILabel!
var navBarView : UIView!
var scrollView : UIScrollView!
var scrollMainView : UIView!
var emailfieldView : UIView!
var emailTextField : UITextField = UITextField() override func viewDidLoad() {
super.viewDidLoad()
setDesign()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
}func setDesign(){
setNavegationBar()
setBackgroundImage()
addScrollView()
}
func setBackgroundImage(){
let backgroundImage = UIImageView(image: UIImage(named: "loginbg.png"))
self.view.addSubview(backgroundImage)
backgroundImage.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = backgroundImage.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = backgroundImage.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = backgroundImage.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 0)
let bottomConst = backgroundImage.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([leadingConst,trailingConst,topConst,bottomConst])
}
func setNavegationBar(){
navigationItem.title = "Join"
view.backgroundColor = UIColor.white
navigationController?.navigationBar.isHidden = true
navigationController?.navigationBar.tintColor = UIColor.white
navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
setNavBarView()
}
func setNavBarView(){
navBarView = UIView()
self.view.addSubview(navBarView)
navBarView.translatesAutoresizingMaskIntoConstraints = false
let guide = view.safeAreaLayoutGuide
let heightCost = navBarView.heightAnchor.constraint(equalToConstant: 64.0)
let leadingCost = navBarView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0.0)
let trailingConst = navBarView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topCost = navBarView.topAnchor.constraint(equalTo: guide.topAnchor, constant: 0.0)
NSLayoutConstraint.activate([trailingConst,heightCost,topCost,leadingCost])
setBackButton()
setNavTitle()
}
func setBackButton(){
backButton = UIButton(type: UIButtonType.custom)
backButton.setImage(UIImage(named: "join_back"), for: UIControlState.normal)
navBarView.addSubview(backButton)
backButton.translatesAutoresizingMaskIntoConstraints = false
let widthCost = backButton.widthAnchor.constraint(equalToConstant: 44.0)
let heightCost = backButton.heightAnchor.constraint(equalToConstant: 44.0)
let leadingCost = backButton.leadingAnchor.constraint(equalTo: navBarView.leadingAnchor, constant: 0.0)
let topCost = backButton.topAnchor.constraint(equalTo: navBarView.topAnchor, constant: 0.0)
NSLayoutConstraint.activate([widthCost,heightCost,topCost,leadingCost])
backButton.addTarget(self, action: #selector(self.backButtonPress), for: UIControlEvents.touchUpInside)
}
func setNavTitle(){
titleLabel = UILabel()
titleLabel.text = "Join Dubai Store"
titleLabel.font = UIFont(name: "Dubai-Regular", size: 22.0)
titleLabel.textAlignment = NSTextAlignment.center
titleLabel.tintColor = UIColor(hexString: "#353535")
navBarView.addSubview(titleLabel)
titleLabel.translatesAutoresizingMaskIntoConstraints = false
let heightCost = titleLabel.heightAnchor.constraint(equalToConstant: 44.0)
let topCost = titleLabel.topAnchor.constraint(equalTo: navBarView.topAnchor, constant: 0.0)
let centerCost = titleLabel.centerXAnchor.constraint(equalTo: navBarView.centerXAnchor)
NSLayoutConstraint.activate([heightCost,topCost,centerCost])
}
@objc func backButtonPress(){
self.view.endEditing(true)
self.dismissView()
}
func addScrollView(){
scrollView = UIScrollView()
view.addSubview(scrollView)
scrollView.layer.borderWidth = 1.0
scrollView.layer.borderColor = UIColor.red.cgColor
scrollView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollView.topAnchor.constraint(equalTo: navBarView.bottomAnchor, constant: 0)
let bottomConst = scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([leadingConst,trailingConst,topConst,bottomConst])
addScrollMainView()
}
func addScrollMainView() {
scrollMainView = UIView()
scrollView.addSubview(scrollMainView)
scrollMainView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollMainView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 0)
let trailingConst = scrollMainView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollMainView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0)
let bottomConst = scrollMainView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([topConst,leadingConst,trailingConst,bottomConst])
emailFieldView()
}
func emailFieldView(){
emailfieldView = UIView()
emailfieldView.isUserInteractionEnabled = true
emailfieldView.translatesAutoresizingMaskIntoConstraints = false
scrollMainView.addSubview(emailfieldView)
let topCost = emailfieldView.topAnchor.constraint(equalTo: scrollMainView.topAnchor, constant: 0.0)
let leadingConst = emailfieldView.leadingAnchor.constraint(equalTo: scrollMainView.leadingAnchor, constant: 0)
let trailingConst = emailfieldView.trailingAnchor.constraint(equalTo: scrollMainView.trailingAnchor, constant: 0)
let heightCost = emailfieldView.heightAnchor.constraint(equalToConstant: 62.0)
NSLayoutConstraint.activate([trailingConst,heightCost,topCost,leadingConst])
//emailTextField = UITextField(frame: CGRect(x: 10, y: 0, width: SCREEN_WIDTH, height: 50))
emailTextField.placeholder = "Email"
emailTextField.layer.borderColor = UIColor.red.cgColor
emailTextField.layer.borderWidth = 1.0
// emailTextField.font = UIFont.systemFont(ofSize: 15)
// emailTextField.borderStyle = UITextBorderStyle.none
// emailTextField.keyboardType = UIKeyboardType.default
// emailTextField.returnKeyType = UIReturnKeyType.done
// //emailTextField.clearButtonMode = UITextFieldViewMode.whileEditing
emailTextField.isUserInteractionEnabled = true
emailTextField.allowsEditingTextAttributes = true
//emailTextField.contentVerticalAlignment = UIControlContentVerticalAlignment.center
emailTextField.addTarget(self, action: #selector(self.textFieldShouldBeginEditing), for: UIControlEvents.touchUpInside)
emailfieldView.addSubview(emailTextField)
emailTextField.translatesAutoresizingMaskIntoConstraints = false
emailTextField.contentMode = UIViewContentMode.left
emailTextField.delegate = self
let etopCost = emailTextField.topAnchor.constraint(equalTo: emailfieldView.topAnchor, constant: 0.0)
let eleadingConst = emailTextField.leadingAnchor.constraint(equalTo: emailfieldView.leadingAnchor, constant: 10)
let etrailingConst = emailTextField.trailingAnchor.constraint(equalTo: emailfieldView.trailingAnchor, constant: -10)
let eheightCost = emailTextField.heightAnchor.constraint(equalToConstant: 50.0)
NSLayoutConstraint.activate([etopCost,eleadingConst,etrailingConst,eheightCost])
self.scrollMainView.bringSubview(toFront: emailTextField)
emailTextField.isAccessibilityElement = true
} }
extension SignupViewController: UITextFieldDelegate {
func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
// return NO to disallow editing.
print("TextField should begin editing method called")
return true
}
func textFieldDidBeginEditing(_ textField: UITextField) {
// became first responder
print("TextField did begin editing method called")
}
func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
// return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
print("TextField should snd editing method called")
return true
}
func textFieldDidEndEditing(_ textField: UITextField) {
// may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called
print("TextField did end editing method called")
}
func textFieldDidEndEditing(_ textField: UITextField, reason: UITextFieldDidEndEditingReason) {
// if implemented, called in place of textFieldDidEndEditing:
print("TextField did end editing with reason method called")
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// return NO to not change text
print("While entering the characters this method gets called")
return true
}
func textFieldShouldClear(_ textField: UITextField) -> Bool {
// called when clear button pressed. return NO to ignore (no notifications)
print("TextField should clear method called")
return true
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
// called when 'return' key pressed. return NO to ignore.
print("TextField should return method called")
// may be useful: textField.resignFirstResponder()
return true
}
}
我只是 运行 你的代码，看起来 scrollMainView 在视图的层次结构中不可见。只需更改约束即可。这是代码：
func addScrollMainView() {
scrollMainView = UIView()
scrollView.addSubview(scrollMainView)
scrollMainView.translatesAutoresizingMaskIntoConstraints = false
let leadingConst = scrollMainView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0)
let trailingConst = scrollMainView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0)
let topConst = scrollMainView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0)
let bottomConst = scrollMainView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
NSLayoutConstraint.activate([topConst,leadingConst,trailingConst,bottomConst])
emailFieldView()
}
顺便说一句，这与你的问题无关，但最好在一开始就创建bg。只需使用以下代码：
func setDesign(){
setBackgroundImage()
setNavegationBar()
addScrollView()
}