how can i access IBOutlet in another class? in swift
I'm sorry i have bad eng skill.
i want access IBOutlet in another class. i found many question in stackoverflow, but all answer not working in my code
firstly this is my code.
ViewController.swift
import UIKit
class ViewController: UIViewController {
@IBOutlet var MainViewController: UIView! = nil
@IBOutlet var LyricsViewController: UIView! = nil
@IBOutlet var ListViewController: UIView! = nil
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
showMainViewController()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func showMainViewController(){
MainViewController.alpha = 1
LyricsViewController.alpha = 0
ListViewController.alpha = 0
}
func showLyricsViewController(){
MainViewController.alpha = 0
LyricsViewController.alpha = 1
ListViewController.alpha = 0
}
func showListViewController(){
MainViewController.alpha = 0
LyricsViewController.alpha = 0
ListViewController.alpha = 1
}
}
and i want access ViewController's function in this class
SecondViewController.swift
import UIKit
class SecondViewController : UIViewController{
@IBOutlet weak var menuButton: UIButton!
var listBoolean = false
override func viewDidLoad() {
super.viewDidLoad()
}
@IBAction func LinkListView(sender: AnyObject) {
if(listBoolean == false){
ViewController().showListViewController()
listBoolean = true
}
else{
ViewController().showMainViewController()
listBoolean = false
}
}
}
func showMainViewController() is work in ViewController's viewDidLoad() but error in SecondViewController with this setance
fatal error : unexpectedly found nil while unwrapping an Optional value
how can i fix this problem?
You have to create a object of view controller and then access it. Ex:-
var dash : abcViewController = storyBoard.instantiateViewControllerWithIdentifier("abc") as! abcViewController
var a = dash.getXYZ()
Like this way you access the variable and function of other view controller.
This is because the ViewController is not yet loaded. You create a variable to store it temporarily. When the ViewController appears, under your viewDidLoad method, assign the variable to the IBOutlet.
Example:
In the FirstViewController you want to pass a string message say "pass message" to SecondViewController and display on a label of IBOutlet. You can't assign the string directly to SecondViewController on FirstViewController . You have to create a string first.
When your SecondViewController loads, in the viewDidLoad method, assign the "pass message" string to the label to display. That is how you display on your IBOutlet.
Just in case:
class FirstViewController: UIViewController{
// All your above codes.
func PassMessage(){
let displayViewController = storyboard!.instantiateViewControllerWithIdentifier("SecondViewController") as! SecondViewController
displayViewController.message = "pass message"
}
}
In SecondViewController
class SecondViewController: UIViewController{
@IBOutlet weak var displayLabel: UILabel!
var message = ""
override func viewDidLoad(){
super.viewDidLoad()
self.displayLabel.text = message
}
}
Note: Assign SecondViewController in the StoryboardID.
我已经使用这个函数来处理以前的类函数操作
let appdel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let nav : UINavigationController! = window.rootViewController as! UINavigationController
for(var i:Int = 0 ; i < nav.viewControllers.count ; i++)
{
let viewc : UIViewController = nav.viewControllers[i]
if(viewc.respondsToSelector("showListViewController"))
{
viewc.performSelector("showListViewController")
}
}