Swift 3 add remove subview and its content dynamically - ios

Question

I am writing my first Swift app for quiz. Each question has random way to render on screen as below screenshot.
I am programming app without story board ie. programmatically. I want to create simple pagination flow for each question within single viewcontroller without using Collocationview, Tableview or navigation.
What I did so far? I have simple viewcontroller with UIView() added as subview. I am adding question components dynamically. Now once user click on continue I wanted remove subview and add new subview with new question. I am able to remove subview but contents on subview seems to be still there as I can see its overwriting.
To get more clarification please view my code.
import UIKit
class QuizController: UIViewController {
let subView = UIView()
var currentQuestion:Int = 1;
let questions = ["This is question 1", "Hello to question 2", "Question 3"]
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = .white
setup_layout()
}
func setup_layout(){
let closeBtn = UIButton(frame: CGRect(x: 5, y: 10, width: 200, height: 50))
closeBtn.backgroundColor = UIColor.red
closeBtn.setTitle("Close", for: .normal)
closeBtn.addTarget(self, action: #selector(close), for: .touchUpInside)
view.addSubview(closeBtn)
//dynamic view
create_subview()
}
func nextQuestion(){
print("Show next")
if let viewWithTag = self.view.viewWithTag(currentQuestion) {
viewWithTag.removeFromSuperview()
currentQuestion += 1;
create_subview()
} else {
print("No!")
}
}
func create_subview(){
let heightOfView = view.frame.size.height
let widthOfView = view.frame.size.width
subView.tag = currentQuestion
subView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.2)
subView.frame = CGRect(x: 0, y: 60, width: self.view.frame.width, height: heightOfView - 60)
self.view.addSubview(subView)
let txtLabel1 = UILabel(frame: CGRect(x: 35, y: 120, width: widthOfView , height: 20))
txtLabel1.text = questions[currentQuestion-1]
txtLabel1.font = txtLabel1.font.withSize(12)
subView.addSubview(txtLabel1)
let nextBtn = UIButton(frame: CGRect(x: 5, y: 300, width: 200, height: 50))
nextBtn.backgroundColor = UIColor.red
nextBtn.setTitle("Continue", for: .normal)
nextBtn.addTarget(self, action: #selector(nextQuestion), for: .touchUpInside)
subView.addSubview(nextBtn)
}
func close(){
self.dismiss(animated: true, completion: nil)
}
}
And this is what I see which I click continue.
NOTE: Initially thought using Collocation or Table view will be more appropriate as I can set to scroll horizontally for each question and fetch questions using REST API and place to each cell. But I want to present next screen to user only once then click on continue. I guess with collectionview user can move to next screen on swipe.

Answer 1

Just found the answer. I assumed removing subview will also remove all components on subview by itself ie. UILable and UIButton in my case.
I have to remove them separately.
for subview in self.subView.subviews {
subview.removeFromSuperview()
}
Now i can add tag to components and remove like this:
for subview in self.subView.subviews {
if (subview.tag == 1) {
subview.removeFromSuperview()
}
}

Answer 2

Why are you removing superviews and adding again and again??
Simply change UILabel.text :)