How to create a global property(variable) in swift programming ? and pass value from other class

Question

I have a class of UITableViewCell and that cell is intialized from another class that contains table view.I want to pass an integer value to cell class from tableview class.

In objective c it was simply done by making global variable and passing values when making instance of global variable class. I do not want any value at declaration time and this global variable will change the value and get the value when it is passing by another class.

I do not know where is mistake please see my code mentioned below-

UITableViewCell class :-

import UIKit

class PostHeaderCell: UITableViewCell {

var loopVariable: Int? // This is global variable that i have written

@IBOutlet weak var viewMain: UIView!
@IBOutlet weak var viewCategory: UIView!
@IBOutlet weak var mainViewHeight: NSLayoutConstraint!
@IBOutlet weak var topLayoutViewCategory: NSLayoutConstraint!
override func awakeFromNib() {
    super.awakeFromNib()
   print(loopVariable)

    viewMain.layer.cornerRadius=5.0
    viewMain.layer.borderColor = UIColor(red: 212.0/255.0, green: 217.0/255.0, blue: 221.0/255.0, alpha: 1.0).CGColor
    viewMain.layer.borderWidth=1.0
    var myVar = 50.0 as CGFloat
     for var i=0;i<loopVariable;i++
    {
        mainViewHeight.constant=mainViewHeight.constant+30
        var postCell :PostCategoryView?
        postCell = NSBundle.mainBundle().loadNibNamed("PostCategoryView", owner: self, options: nil)[0] as? PostCategoryView
        postCell!.frame=CGRectMake(10,myVar+10,postCell!.frame.size.width,50)
        print(postCell)
        myVar = myVar + 55.0;

    }
    self.layoutSubviews()
  }

    override func setSelected(selected: Bool, animated: Bool) {
      super.setSelected(selected, animated: animated)

    // Configure the view for the selected state
  }
}

Now, I implemented this UITableViewCell class in another class and passing loop variable value from that class, Please look below mentioned code for calling and instantiating PostHeaderCell- Class B:-

 var cell:PostHeaderCell! =     tableView.dequeueReusableCellWithIdentifier("PostHeaderCell",  forIndexPath: indexPath) as! PostHeaderCell
  cell.loopVariable=2
  return cell

Note -: I want to initialise the value of loop variable from Class B but it always give nil ( i have passed 2 as a value for loopVariable).

Leonardo, I think it is on the top level if i am moving it then getting compiler error "PostHeaderCell does not have member variable loopVariable" — Anuj Kumar Rai
– Anuj Kumar Rai, Commented May 6, 2015 at 4:50

GoZoner · Accepted Answer · 2015-05-06 05:05:43Z

1

What you need is a 'class' variable, declare with static. Here is a simplified example:

class Foo {
  static var counter : Int = 0

  init () {
    Foo.counter++
  }
}

In this example, everytime you create a new Foo the counter gets incremented. As such:

  9> Foo()
$R0: Foo = {}
 10> Foo.counter
$R1: Int = 1
 11> Foo()
$R2: Foo = {}
 12> Foo.counter
$R3: Int = 2

But, the increment is just an example of how the counter value is scoped to the class, not to an instance.

For your case, you can assign the counter with

Foo.counter = 10

and you can use it within other functions:

class Foo { 
  // ...

  func awakeFromNib () {
    for var i = 0; i < Foo.counter; i++ {
      // ...
    }
  }
}

answered May 6, 2015 at 5:05

GoZoner

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