如何在这两个文本字段具有值之前禁用此完成按钮？

Question

我的目标是在这两个文本字段都为空时禁用完成按钮。我有顶部按钮的逻辑，但是一旦顶部文本字段“taskNameTextFIeld”至少有一个字符，就会启用完成按钮。我不希望用户能够在“timeTextField”为空时按下完成。你可以在textField（）中看到我到目前为止。

import UIKit

protocol AddNewTaskViewControllerDelegate: class {
    func addNewTaskViewControllerDidCancel(_ controller: AddNewTaskViewController)
    func addNewTaskViewController(_ controller: AddNewTaskViewController, 
    didFinishAdding item: TaskData)
}

class AddNewTaskViewController: UITableViewController, UITextFieldDelegate {

@IBOutlet weak var taskNameTextFIeld: UITextField!
@IBOutlet weak var timeTextFIeld: UITextField!
@IBOutlet weak var doneBarButton: UIBarButtonItem!

weak var delegate: AddNewTaskViewControllerDelegate?

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let oldText = textField.text! as NSString
    let newText = oldText.replacingCharacters(in: range, with: string) as NSString
    doneBarButton.isEnabled = newText.length > 0
    return true
}

@IBAction func cancel(_ sender: Any) {
    delegate?.addNewTaskViewControllerDidCancel(self)
}

@IBAction func done(_ sender: Any) {
    let item = TaskData()
    item.task = taskNameTextFIeld.text!
    item.time = timeTextFIeld.text!

    delegate?.addNewTaskViewController(self, didFinishAdding: item)
}

func textFieldShouldReturn(_ TextField: UITextField) -> Bool {
    self.view.endEditing(true)
    return false
}

override func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
    return nil
}

override func viewDidLoad() {
    super.viewDidLoad()
    self.taskNameTextFIeld.delegate = self;
    self.timeTextFIeld.delegate = self;
    // Do any additional setup after loading the view.
}
}

Answer 1

问题是您没有检查两个字段。变化：

doneBarButton.isEnabled = newText.length > 0

要对事物进行实际检查：

if taskNameTextFIeld.text.length > 0 && timeTextFIeld.text.length > 0 {
    doneBarButton.isEnabled = newText.length > 0
}

另外，我建议将两个文本字段的名称更改为Field而不是Field。

Answer 2

以下是我如何解决问题的一些细节。文本字段本身没有长度成员，因此我比较了字符数。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let oldText = textField.text! as NSString
    let newText = oldText.replacingCharacters(in: range, with: string) as NSString
    //doneBarButton.isEnabled = newText.length > 0
    if (taskNameTextFIeld.text?.characters.count)! > 0 && (timeTextFIeld.text?.characters.count)! > 0 {
        doneBarButton.isEnabled = newText.length > 0
    }
    return true
}