将导航栏项目按钮设置为新标题 [英] Set navbar item button to new title

问题描述

美好的一天.我面临一个奇怪的问题，当我选择一行时，我想在下一个中将正确的导航项设置为完成".我试过了，它奏效了.但它打破了，因为实现 doneEditing 主体的函数只在下一个视图控制器中，任何帮助将不胜感激.这是我的代码:

Good day. I'm facing a weird issue, I'd like to set the right navigation item to Done in my next when I've selected a row. I tried it, and it's worked. But it's breaking however, because the function which implements the doneEditing body, is only in the next view controller, any help will be really appreciated. This is my code:

 override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "editContact" {

            let indexPath = tableView.indexPathForSelectedRow()
            let destinationVC: NewCategoryViewController = segue.destinationViewController as! NewCategoryViewController
            let contact:Contact = fetchedResultController.objectAtIndexPath(indexPath!) as! Contact
            destinationVC.contact = contact
            var rightAddBarButtonItem:UIBarButtonItem = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.Plain, target: self, action: "doneEditing:")
            destinationVC.navigationItem.rightBarButtonItem = rightAddBarButtonItem
        }
    }

我的下一个视图控制器是:

and my next view controller is :

import UIKit
import CoreData


class NewCategoryViewController: UIViewController {

    // MARK: - Properties
    var contact: Contact? = nil

// initialize the core data context:
let context = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

// MARK: - Outlets
@IBOutlet weak var imageHolder: UIImageView!
@IBOutlet weak var nameField: UITextField!
@IBOutlet weak var emailField: UITextField!
@IBOutlet weak var phoneField: UITextField!
@IBOutlet weak var categoryField: UITextField!

// MARK: - Actions
@IBAction func savebtn(sender: AnyObject) {

    let entity = NSEntityDescription.entityForName("Contact", inManagedObjectContext: context!)
    let newContact = Contact(entity: entity!, insertIntoManagedObjectContext: context)
        newContact.name = nameField.text
        newContact.email = emailField.text
        newContact.phone = phoneField.text
        //newContact.photo = UIImageJPEGRepresentation(imageHolder.image, 1)

    var error: NSError?

    context?.save(&error)

    if let errorSaving = error {
        var alert = UIAlertController(title: "Alert", message: "Couldn't save contact !!!", preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
        self.presentViewController(alert, animated: true, completion: nil)
    } else {
        nameField.text = ""
        emailField.text = ""
        phoneField.text = ""
        var alert = UIAlertController(title: "Notification", message: "Contact added", preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
        self.presentViewController(alert, animated: true, completion: nil)
    }

}


override func viewDidLoad() {
    super.viewDidLoad()
    self.title = contact?.name

    if contact != nil {
        nameField.text = contact?.name
        emailField.text = contact?.email
        phoneField.text = contact?.phone

    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func doneEditing() {

}

}

推荐答案

将目标从 self 更改为 destinationVC.

change target from self to destinationVC.

使用这个:

var rightAddBarButtonItem:UIBarButtonItem = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.Plain, target: destinationVC, action: "doneEditing:")

self 应该在选择器定义在进行调用的同一个类中时使用.在这种情况下，选择器位于一个单独的类中.

self should be used when the selector is defined in the same class which makes the call. In this case the selector is in a separate class.

或

我建议您在 NewCategoryViewController 的 viewDidLoad 方法中添加右侧栏按钮.在这种情况下，代码将是:

I would suggest you to add the right bar button in the viewDidLoad method of NewCategoryViewController. In which case the code will be:

self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.Plain, target: self, action: "doneEditing:")

AND将 doneEditing: 方法实现为

func doneEditing(sender: UIBarButtonItem) {

}

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