onClick event in a for loop (Swift) not working - ios

Question

Data sharing between two view controllers by using segue is not working in for loop. I am using Xcode9 and Swift
swift4
ViewController.swift
import UIKit
import SwiftyJSON
import Alamofire
class ViewController: UIViewController {
var distnames = [String]()
var distcodes = [String]()
var data1: [AnyObject] = []
var values = [String]()
var values1 = [String]()
var current_arr :[String] = []
var ofcnames = " ";
var ofccodes = " ";
var code = " ";
var testtext = "";
var id = "";
var tiTle = "";
var releaseYear = "";
#IBOutlet weak var Verticalstackview: UIStackView!
#IBOutlet weak var scrollview: UIScrollView!
#IBOutlet weak var testlabel: UILabel!
#IBOutlet weak var mainView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
print("code is \(code)")
self.values = [String]()
self.values1 = [String]()
self.ofcnames = "";
self.ofccodes = "";
Alamofire.request("https://facebook.github.io/react-native/movies.json")
.responseJSON { (response) in
if ((response.result.value) != nil) {
let jsondata = JSON(response.result.value!)
// print(jsondata)
if let da = jsondata["movies"].arrayObject
{
self.data1 = da as [AnyObject]
print("resp is \(da) ")
}
print("respcode count is \(self.data1.count) ")
self.Verticalstackview.height(constant: 40)
self.mainView.height(constant: CGFloat(40 * self.data1.count))
self.scrollview.height(constant: CGFloat(40 * self.data1.count))
for distics in self.data1 {
if let resp = distics as? NSDictionary {
self.id = resp["id"] as! String
self.tiTle = resp["title"] as! String
self.releaseYear = resp["releaseYear"] as! String
let stackView = UIStackView()
stackView.height(constant: 40)
stackView.distribution = .fill
stackView.alignment = .fill
stackView.axis = .horizontal
stackView.spacing = 5
let lblId = UILabel()
lblId .text = "\(self.id)"
lblId .font = UIFont(name: "verdana", size: 15.0)
lblId .textAlignment = .center
lblId .textColor = .gray
lblId .numberOfLines = 0
lblId .width(constant: 55)
let lbltiTle = UILabel()
lbltiTle.text = "\(self.tiTle)"
lbltiTle.font = UIFont(name: "verdana", size: 15.0)
lbltiTle.textAlignment = .left
lbltiTle.textColor = .black
lbltiTle.numberOfLines = 0
lbltiTle.width(constant: 120)
let tap = UITapGestureRecognizer.init(target:self,action: #selector(self.tapFunction) )
lbltiTle.isUserInteractionEnabled = true
lbltiTle.addGestureRecognizer(tap)
self.testtext = lbltiTle.text!
let lblRYear = UILabel()
lblRYear.text = "\(self.releaseYear)"
lblRYear.font = UIFont(name: "verdana", size: 15.0)
lblRYear.textAlignment = .right
lblRYear.textColor = .black
lblRYear.numberOfLines = 0
lblRYear.width(constant: 100)
stackView.addArrangedSubview(lblId )
stackView.addArrangedSubview(lbltiTle)
stackView.addArrangedSubview(lblRYear)
self.Verticalstackview.addArrangedSubview(stackView)
}
}
}
print(self.values1)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#objc func tapFunction(sender:UITapGestureRecognizer) {
print("tap working")
self.performSegue(withIdentifier: "Segue", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let secondcntroller = segue.destination as! SecondViewController
secondcntroller.mystring = self.testtext
}
}
extension UIView{
func height(constant : CGFloat){
setConstraint(value: constant,attribute: .height)
}
func width(constant : CGFloat){
setConstraint(value: constant,attribute: .width)
}
private func removeConstraint(attribute: NSLayoutAttribute){
constraints.forEach {
if $0.firstAttribute == attribute
{
removeConstraint($0)
}
}
}
private func setConstraint(value:CGFloat ,attribute: NSLayoutAttribute){
removeConstraint(attribute: attribute)
let Constraint =
NSLayoutConstraint(item: self,
attribute: attribute,
relatedBy: NSLayoutRelation.equal,
toItem: nil,
attribute: NSLayoutAttribute.notAnAttribute,
multiplier: 1,
constant: value)
self.addConstraint(Constraint)
}
}
SecondViewController.swift
import UIKit
class SecondViewController: UIViewController {
#IBOutlet weak var label: UILabel!
var mystring = String()
override func viewDidLoad() {
super.viewDidLoad()
label.text=mystring
}
}
When I click the movie name text, I want that to be displayed on the second view using segue.
https://i.stack.imgur.com/dvm8j.png
But always it displays the last movie name. Please assist me sorting this issue.
https://i.stack.imgur.com/UqyqM.png

Answer 1

You should update your tapFunction
#objc func tapFunction(sender:UITapGestureRecognizer) {
let touchedLabel = sender.view as! UILabel
self.testtext = touchedLabel.text
self.performSegue(withIdentifier: "Segue", sender: self)
}
Hope it helps
EDIT
Now as you wants to pass the multiple values, what you can do is:
First change your for in loop from
for distics in self.data1 {
To
for (index, distics) in self.data1.enumerated() {
Now, set the tag to your label below this line
lbltiTle.addGestureRecognizer(tap)
// Add tag to your label
lbltiTle.tag = index
//**TIP: You should name the variables in camelCase format**
Now modify your function, that detects the tap on label and get the object with index being passed with the label in form of it's tag. Modify it to.
#objc func tapFunction(sender:UITapGestureRecognizer) {
let touchedLabel = sender.view as! UILabel
let touchedIndex = touchedLabel.tag
let selectedDict: NSDictionary = self.data1[touchedIndex]
print("selectedDict:\(selectedDict)")
self.performSegue(withIdentifier: "Segue", sender: self)
}
You can print the required values from it.
NOTE: For the pure swift approach, you should Avoid using NSDictionary, better use [String: Any] which is a key value pair.
Hope it helps

Answer 2

The self.testtext property from ViewController is not set properly. It should be set every time the tapFunction() is called.
Any way I recomand you to use UITabiewViewController and a data source array which should hold all your elements to display.

Answer 3

Issue
That is because you are passing testtext as a parameter to the next ViewController.mystring. testtext is being changed every time on the loop and the last time it is being changed it is on the last element. Therefore you need to save an index to know where you pressed.
Solution
Change your for loop to get the index of the element you're iterating as above
for index in 0..<self.data1.count {
let distics = self.data1[index]
// Other lines of code
lbltiTle.tag = index
}
Change your handler as below
#objc func tapFunction(sender:UITapGestureRecognizer) {
print("tap working")
guard let index = sender.view?.tag,
let title = (self.data1[index] as? NSDictionary)["title"] else { return }
testtext = title
self.performSegue(withIdentifier: "Segue", sender: self)
}

Answer 4

Add one more function for your label.
lbltiTle.target(forAction: onClickLabel, withSender:)
Definition -
func onClickLabel(sender: UILabel) {
self.testtext = sender.text
}
Call this in your tap function