ios - 禁用带有 textFieldDidBeginEditing 的 UIButton 需要单击 UITextField 才能生效

Question

使用 UITextFieldDelegate，我根据 3 个 UITextFields 是否包含信息来禁用我的 UIButton“btnSignup”。目前，它的工作正常减去 UIButton react 的事实(再次运行 if 语句)，我必须点击 UITextField。当我输入内容并返回删除它时也是如此。 UIButton 保持事件状态，直到我点击 UITextField(如果我点击提交而不点击其他地方，我可以提交，但事实并非如此。)

class MainVC: UIViewController, UITextFieldDelegate {

    @IBOutlet var receiveName: UITextField!
    @IBOutlet var receiveEmail: UITextField!
    @IBOutlet var receivePhone: UITextField!
    @IBOutlet var btnSignup: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.btnSignup.enabled = false
        self.btnSignup.alpha = 0.3

        self.receiveName.delegate = self
        self.receiveEmail.delegate = self
        self.receivePhone.delegate = self

    func textFieldDidBeginEditing(textField: UITextField) {

        if countElements(receiveName.text) > 0 && countElements(receiveEmail.text) > 0 && countElements(receivePhone.text) > 0 {
            self.btnSignup.enabled = true
            self.btnSignup.alpha = 1
        } else {
            self.btnSignup.enabled = false
            self.btnSignup.alpha = 0.3
        }
    }
}

我正在寻找一种能够提供更实时效果的解决方案。如果 UITextField 在任何时候被编辑，该函数应该监听和响应。

Answer 1

使用与您的代码接近的东西，我可以按如下方式执行此操作。我添加了 3 个级别。用于记录文本字段是否输入了内容的变量。我在文本字段中添加了标签。我更改了 UITextFieldDelegate 类 func 并测试了所有三个字段都有文本。当您在第三个字段中输入一个字段时，按钮会亮起!

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    var receiveNameBool = false
    var receiveEmailBool = false
    var receivePhoneBool = false

    @IBOutlet var receiveName: UITextField!
    @IBOutlet var receiveEmail: UITextField!
    @IBOutlet var receivePhone: UITextField!
    @IBOutlet var btnSignup: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.btnSignup.enabled = false
        self.btnSignup.alpha = 0.3

        self.receiveName.delegate = self
        self.receiveEmail.delegate = self
        self.receivePhone.delegate = self

        }

    func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool {

        if textField.tag == 1 {
            receiveNameBool = true
        } else if textField.tag == 2 {
            receiveEmailBool = true
        } else if textField.tag == 3 {
            receivePhoneBool = true
        }

        if receiveNameBool && receiveEmailBool && receivePhoneBool {
            self.btnSignup.enabled = true
            self.btnSignup.alpha = 1
        } else {
            self.btnSignup.enabled = false
            self.btnSignup.alpha = 0.3
        }
        return true
    }
}

好的，在第二个版本中，我使用了您使用的 textFieldDidBeginEditing 函数。在这种情况下，您在第三个字段中单击的第二个按钮已启用。在这两个示例中，如果用户删除了他们输入的数据，您仍然需要编写代码来处理这种情况。但是上面的第一个示例可以满足您的需求。

导入 UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    var receiveNameBool = false
    var receiveEmailBool = false
    var receivePhoneBool = false

    @IBOutlet var receiveName: UITextField!
    @IBOutlet var receiveEmail: UITextField!
    @IBOutlet var receivePhone: UITextField!
    @IBOutlet var btnSignup: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.btnSignup.enabled = false
        self.btnSignup.alpha = 0.3

        self.receiveName.delegate = self
        self.receiveEmail.delegate = self
        self.receivePhone.delegate = self

        }

    func textFieldDidBeginEditing(textField: UITextField) {

        if textField.tag == 1 {
            receiveNameBool = true
        } else if textField.tag == 2 {
            receiveEmailBool = true
        } else if textField.tag == 3 {
            receivePhoneBool = true
        }

        if receiveNameBool && receiveEmailBool && receivePhoneBool {
            self.btnSignup.enabled = true
            self.btnSignup.alpha = 1
        } else {
            self.btnSignup.enabled = false
            self.btnSignup.alpha = 0.3
        }
    }
}