Cannot assign to property: 'self' is immutable - xcode

Question

I am creating a page view application. I have written code for the ViewController:
import UIKit
class ViewController: UIViewController {
var pageViewController : UIPageViewController!
var pageTitles : NSArray!
var pageImages : NSArray!
#IBAction func restartAction(sender: AnyObject) {}
override func viewDidLoad() {
super.viewDidLoad()
self.pageTitles = NSArray(objects: "This Is Page One!", "This Is Page Two!")
self.pageImages = NSArray(objects: "page1", "page2")
self.pageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("PageViewController") as! UIPageViewController
self.pageViewController.dataSource = self // <–– Error
let startVC = self.viewControllerAtIndex(0) as ContentViewController
let viewControllers = NSArray(object: startVC)
self.pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: .Forward, animated: true, completion: nil)
self.pageViewController.view.frame = CGRectMake(0, 30, self.view.frame.width, self.view.frame.height - 60)
self.addChildViewController(self.pageViewController)
self.view.addSubview(self.pageViewController.view)
self.pageViewController.didMoveToParentViewController(self)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func viewControllerAtIndex(index: Int) -> ContentViewController {
if ((self.pageTitles.count == 0) || (index >= self.pageTitles.count)) {
return ContentViewController()
}
let vc : ContentViewController = self.storyboard?.instantiateViewControllerWithIdentifier("ContentViewController") as! ContentViewController
vc.imageFile = self.pageImages[index] as! String
vc.titleText = self.pageTitles[index] as! String
vc.pageIndex = index
return vc
}
func pageViewController(pageViewController: UIPageViewController, viewcontrollerBeforeViewController viewController: UIViewController) ->UIViewController? {
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if index == 0 || index == NSNotFound {
return nil
}
index--
return self.viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewcontrollerAfterViewController viewController: UIViewController) ->UIViewController? {
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if index == NSNotFound {
return nil
}
index++
if index == self.pageTitles.count {
return nil
}
return self.viewControllerAtIndex(index)
}
}
But I am getting an error on this line self.pageViewController.dataSource = self. The error is:
Cannot assign to property: 'self' is immutable
I am unsure of why self is immutable and how to fix it. If someone could please help, thanks in advance.

Answer 1

In swift you'll need to call self.pageViewController.setDelegate(self)
Delegates have been declared as methods, not properties in some cases

Answer 2

I think the compiler is not being very helpful here - try declaring the controller as following datasource protocol and see if that fixes this odd error
class ViewController: UIViewController, UIPageViewControllerDataSource { etc