如何从不同的视图控制器调用函数？

Question

我有一个基本上是笔记应用程序的东西，我正在尝试从一个视图控制器调用另一个视图控制器中的函数。我该怎么做，或者有更好的方法吗？

这里是我尝试调用函数的地方

class NoteDetailViewController: UIViewController
{
    @IBOutlet weak var funcButton: UIButton!

    @IBAction func funcButTouched(sender: UIButton)
    {
     // where i want to call the function
    }
}

以及功能在哪里

class ListTableViewController: UITableViewController
{
    // the function
    func wordCount()
    {
        var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
        for (index, element) in contentArr.enumerate()
        {
            let location = conciseArr.indexOf(element)
            if (location != nil)
            {
                contentArr[index] = inflatedArr[location!]
                afterStr = contentArr.joinWithSeparator(" ")
                Project.sharedInstance.after = afterStr
            }
        }
    }
}

我试过只创建一个 ListTableViewController 的实例并以这种方式调用该函数，但我收到了一个错误。

Answer 1

你可以使用 delegation.

首先，声明一个委托协议。这应该在您的 NoteDetailViewController.swift 文件中，但在 class 声明之外：

protocol NoteDetailViewControllerDelegate: class {
    func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}

接下来，将代表属性添加到您的 NoteDetailViewController:

weak var delegate: NoteDetailViewControllerDelegate?

现在，我们使用 @IBAction 来告诉委托人，这将是 ListTableViewController:

@IBAction func funcButTouched(sender: UIButton)
{
    delegate?.noteDetailViewControllerButtonTouched(self)
}

最后，回到 ListTableViewController（假设这个控制器是显示 NoteDetailViewController 之前的控制器），遵守协议并使用 prepareForSegue 将委托设置为它自己:

class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate {
    // ... more stuff ...

    // Implement the delegate protocol
    func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
        // Do something! The button was pressed! 
        wordCount()
    }
    // Set ourselves as delegate when we are about to show the other view controller
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let yourVC = segue.destinationViewController as? NoteDetailViewController {
            yourVC.delegate = self
        }
    }
}

你应该以这样的方式结束：

NoteDetailViewController.swift:

class NoteDetailViewController: UIViewController
{
    @IBOutlet weak var funcButton: UIButton!
    weak var delegate: NoteDetailViewControllerDelegate?

    @IBAction func funcButTouched(sender: UIButton)
    {
        delegate?.noteDetailViewControllerButtonTouched(self)
    }
}

protocol NoteDetailViewControllerDelegate: class {
    func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}

ListTableViewController.swift:

class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate
{
    // the function
    func wordCount()
    {
        var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
        for (index, element) in contentArr.enumerate()
        {
            let location = conciseArr.indexOf(element)
            if (location != nil)
            {
                contentArr[index] = inflatedArr[location!]
                afterStr = contentArr.joinWithSeparator(" ")
                Project.sharedInstance.after = afterStr
            }
        }
    }
    // Implement the delegate protocol
    func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
        // Do something! The button was pressed! 
        wordCount()
    }
    // Set ourselves as delegate when we are about to show the other view controller
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let yourVC = segue.destinationViewController as? NoteDetailViewController {
            yourVC.delegate = self
        }
    }
}

Answer 2

只需按照下面的代码操作即可，非常简单 :-

NoteDetailViewController.swift:

class NoteDetailViewController: UIViewController
{
    @IBOutlet weak var funcButton: UIButton!

    var parentListTableView : ListTableViewController!
    @IBAction func funcButTouched(sender: UIButton)
    {
        parentListTableView.wordCount()

    }
}

ListTableViewController.swift:

class ListTableViewController: UITableViewController
{
    // the function
    func wordCount()
    {
        var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
        for (index, element) in contentArr.enumerate()
        {
            let location = conciseArr.indexOf(element)
            if (location != nil)
            {
                contentArr[index] = inflatedArr[location!]
                afterStr = contentArr.joinWithSeparator(" ")
                Project.sharedInstance.after = afterStr
            }
        }
    }

    // Set ourselves as delegate when we are about to show the other view controller
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let yourVC = segue.destinationViewController as? NoteDetailViewController {
            yourVC.parentListTableView = self
        }
    }
}

如何从不同的视图控制器调用函数？

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