How to create custom view programmatically in swift having controls text field, button etc

I am trying to access the MyCustomView from another class using the following code in ViewController.swift ..

var view = MyCustomView(frame: CGRectZero)

.. in the viewDidLoad method. The problem is the view does not get initialized in the simulator.

I have already set class in storyboard for the current ViewController.

class MyCustomView: UIView {
    var label: UILabel = UILabel()
    var myNames = ["dipen","laxu","anis","aakash","santosh","raaa","ggdds","house"]
    
    override init(){
        super.init()
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.addCustomView()
    }
    
    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func addCustomView() {
        label.frame = CGRectMake(50, 10, 200, 100)
        label.backgroundColor=UIColor.whiteColor()
        label.textAlignment = NSTextAlignment.Center
        label.text = "test label"
        label.hidden=true
        self.addSubview(label)
        
        var btn: UIButton = UIButton()
        btn.frame=CGRectMake(50, 120, 200, 100)
        btn.backgroundColor=UIColor.redColor()
        btn.setTitle("button", forState: UIControlState.Normal)
        btn.addTarget(self, action: "changeLabel", forControlEvents: UIControlEvents.TouchUpInside)
        self.addSubview(btn)
        
        var txtField : UITextField = UITextField()
        txtField.frame = CGRectMake(50, 250, 100,50)
        txtField.backgroundColor = UIColor.grayColor()
        self.addSubview(txtField)
    }

The CGRectZero constant is equal to a rectangle at position (0,0) with zero width and height. This is fine to use, and actually preferred, if you use AutoLayout, since AutoLayout will then properly place the view.

But, I expect you do not use AutoLayout. So the most simple solution is to specify the size of the custom view by providing a frame explicitly:

customView = MyCustomView(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
self.view.addSubview(customView)

Note that you also need to use addSubview otherwise your view is not added to the view hierarchy.

Swift 3 / Swift 4 Update:

let screenSize: CGRect = UIScreen.main.bounds
let myView = UIView(frame: CGRect(x: 0, y: 0, width: screenSize.width - 10, height: 10))
self.view.addSubview(myView)

var customView = UIView()


@IBAction func drawView(_ sender: AnyObject) {

    customView.frame = CGRect.init(x: 0, y: 0, width: 100, height: 200)
    customView.backgroundColor = UIColor.black     //give color to the view 
    customView.center = self.view.center  
    self.view.addSubview(customView)
       }

let viewDemo = UIView()
viewDemo.frame = CGRect(x: 50, y: 50, width: 50, height: 50)
self.view.addSubview(viewDemo)

view = MyCustomView(frame: CGRectZero)

In this line you are trying to set empty rect for your custom view. That's why you cant see your view in simulator.