快速聚焦文本字段 [英] focusing a text field in swift
问题描述
我在注册屏幕上有4个文本字段，并且已对其进行设置，以便当用户在每个文本字段上按next时，将集中显示下一个文本字段.下面的代码:
I have 4 textfields on a register screen and i have it set up so that when the user presses next on each text field, the next text field is focused. Code below:
func textFieldShouldReturn(textField: UITextField) -> Bool {
if (textField == self.fNameField) {
textField.resignFirstResponder()
self.sNameField.becomeFirstResponder()
}
else if (textField == self.sNameField) {
self.emailField.becomeFirstResponder()
} else if (textField == self.emailField) {
self.passwordField.becomeFirstResponder()
}
else{
var thereWereErrors = checkForErrors()
if !thereWereErrors
{
//conditionally segue to next screen
}
}
return true
}
在返回最后一个文本字段时，我正在调用一个检查错误的功能(如下).在此范围内，如果任何字段存在问题，我都希望重点关注该文本字段，以便用户可以轻松地对其进行更正.发生的情况是出现错误的文本字段聚焦了一秒钟(如checkForErrors函数所指示)，但随后焦点又切换回了密码文本字段.我还尝试将self.passwordField.resignFirstResponder()添加到上述函数的最后一个其他位置，这会使密码字段失去焦点，但是遇到问题的文本字段根本无法获得焦点(甚至没有像以前一样).我解决了吗?
On the return of the final text field, I am calling a check for errors function (below). Within that if there is an issue with any field I want to focus that text field so the user can easily correct it. What is happening is that the text field with the error is focusing (as instructed by the checkForErrors functions)for a second but then the focus is switching back to the password text field. I also tried adding in self.passwordField.resignFirstResponder() into the last else of the above function and that makes the password field lose focus but then the text field with the issue encountered is not gaining focus at all (not even for a second as before) How can I fix this?
func checkForErrors() -> Bool
{
var errors = false
let title = "Error"
var message = ""
if fNameField.text.isEmpty {
errors = true
message += "First name empty"
alertWithTitle(title, message: message, ViewController: self)
self.fNameField.becomeFirstResponder()
}
else if sNameField.text.isEmpty
{
errors = true
message += "Surname empty"
alertWithTitle(title, message: message, ViewController: self)
self.sNameField.becomeFirstResponder()
}
else if emailField.text.isEmpty
{
errors = true
message += "Email empty"
alertWithTitle(title, message: message, ViewController: self)
self.emailField.becomeFirstResponder()
}
else if !isValidEmail(emailField.text)
{
errors = true
message += "Invalid Email Address"
alertWithTitle(title, message: message, ViewController: self)
self.emailField.becomeFirstResponder()
}
else if passwordField.text.isEmpty
{
errors = true
message += "Password empty"
alertWithTitle(title, message: message, ViewController: self)
self.passwordField.becomeFirstResponder()
}
else if count(passwordField.text.utf16)<8
{
errors = true
message += "Password must be at least 8 characters"
alertWithTitle(title, message: message, ViewController: self)
self.passwordField.becomeFirstResponder()
}
return errors
}
请注意，我已经包含了textField委托.
Note I have included the textField delegate.
具有标题功能的警报:
func alertWithTitle(title: String!, #message: String, #ViewController: UIViewController) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
let action = UIAlertAction(title: "OK", style: .Cancel, handler: nil)
alert.addAction(action)
ViewController.presentViewController(alert, animated: true, completion: nil)
}
推荐答案
这对我有用:
import UIKit
class ViewController:UIViewController, UITextFieldDelegate {
@IBOutlet weak var fNameField: UITextField!
@IBOutlet weak var sNameField: UITextField!
@IBOutlet weak var emailField: UITextField!
@IBOutlet weak var passwordField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
fNameField.delegate = self
sNameField.delegate = self
emailField.delegate = self
passwordField.delegate = self
}
func isValidEmail (test:String) ->Bool{
// your email validation here...
return true
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
if (textField == self.fNameField) {
self.sNameField.becomeFirstResponder()
}
else if (textField == self.sNameField) {
self.emailField.becomeFirstResponder()
} else if (textField == self.emailField) {
self.passwordField.becomeFirstResponder()
}
else{
var thereWereErrors = checkForErrors()
if !thereWereErrors
{
//conditionally segue to next screen
}
}
return true
}
func checkForErrors() -> Bool
{
var errors = false
let title = "Error"
var message = ""
if fNameField.text.isEmpty {
errors = true
message += "First name empty"
alertWithTitle(title, message: message, ViewController: self, toFocus:self.fNameField)
}
else if sNameField.text.isEmpty
{
errors = true
message += "Surname empty"
alertWithTitle(title, message: message, ViewController: self, toFocus:self.sNameField)
self.sNameField.becomeFirstResponder()
}
else if emailField.text.isEmpty
{
errors = true
message += "Email empty"
alertWithTitle(title, message: message, ViewController: self, toFocus:self.emailField)
}
else if !isValidEmail(emailField.text)
{
errors = true
message += "Invalid Email Address"
alertWithTitle(title, message: message, ViewController: self, toFocus:self.emailField)
}
else if passwordField.text.isEmpty
{
errors = true
message += "Password empty"
alertWithTitle(title, message: message, ViewController: self, toFocus:passwordField)
}
else if count(passwordField.text.utf16)<8
{
errors = true
message += "Password must be at least 8 characters"
alertWithTitle(title, message: message, ViewController: self, toFocus:self.passwordField)
}
return errors
}
func alertWithTitle(title: String!, message: String, ViewController: UIViewController, toFocus:UITextField) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
let action = UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel,handler: {_ in
toFocus.becomeFirstResponder()
});
alert.addAction(action)
ViewController.presentViewController(alert, animated: true, completion:nil)
}
}
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