XMLParser Delegate Methods not Called - ios

Question

I'm trying to abstract an XML parser into a custom class to run it from a VC. It compiles perfectly and my error handler shows up success. However, the actual delegate methods are skipped over. No data is getting parsed.
It all ran fine when I had every running it the VC, but I am now try to get away from spaghetti code.
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let parser = XMLParserHelper()
//try create file for persistent data
//CreatePlist.createPlist()
parser.runParser()
}
}
class XMLParserHelper: NSObject, XMLParserDelegate {
//list type variables to hold XML values (update list base on XML structure):
static var station: String = ""
static var latitude: String = ""
static var longitude: String = ""
private static var code: String = ""
private static var id: String = ""
//reusable method type veriales (do not touch)
static var strXMLData:String = ""
static var currentElement:String = ""
static var passData:Bool=false
static var passName:Bool=false
static var xmlParser = XMLParser()
//parser methods
func runParser(){
let xmlPath = Bundle.main.url(forResource: "station", withExtension: "xml")
let xmlParser = XMLParser(contentsOf: (xmlPath)!)
xmlParser?.delegate = self
let success:Bool = xmlParser!.parse()
xmlParser?.parse()
if success {
print("parse success!")
print(XMLParserHelper.currentElement)
} else {
print("parse failure!")
}
}
private static func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {
XMLParserHelper.currentElement=elementName;
if (elementName=="StationDesc" || elementName=="StationLatitude" || elementName=="StationLongitude" || elementName=="StationCode" || elementName=="StationId" ) {
if (elementName=="StationDesc") {
XMLParserHelper.passName=true;
}
XMLParserHelper.passData=true;
}
}
private static func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
XMLParserHelper.currentElement="";
if (elementName=="StationDesc" || elementName=="StationLatitude" || elementName=="StationLongitude" || elementName=="StationCode" || elementName=="StationId" ) {
if(elementName=="StationDesc") {
XMLParserHelper.passName=false;
}
XMLParserHelper.passData=false;
}
}
private static func parser(_ parser: XMLParser, foundCharacters string: String) {
if (XMLParserHelper.passName) {
XMLParserHelper.strXMLData=XMLParserHelper.strXMLData+"\n\n"+string
}
if (XMLParserHelper.passData) {
//ready content for codable struct
switch XMLParserHelper.currentElement {
case "StationDesc":
XMLParserHelper.station = string
case "StationLatitude":
XMLParserHelper.latitude = string
case "StationLongitude":
XMLParserHelper.longitude = string
case "StationCode":
XMLParserHelper.code = string
case "StationId":
XMLParserHelper.id = string
print(string)
default:
XMLParserHelper.id = string
}
}
}
func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
print("failure error: ", parseError)
}
}

Answer 1

To make XMLParserDelegate methods work, all the methods needs to be non-static, non-private methods.
So, all the properties should also be non-static.
class XMLParserHelper: NSObject, XMLParserDelegate {
//list type variables to hold XML values (update list base on XML structure):
var station: String = ""
var latitude: String = ""
var longitude: String = ""
private var code: String = ""
private var id: String = ""
//reusable method type veriales (do not touch)
var strXMLData: String = ""
var currentElement: String = ""
var passData: Bool = false
var passName: Bool = false
//parser methods
func runParser() {
let xmlURL = Bundle.main.url(forResource: "station", withExtension: "xml")!
let xmlParser = XMLParser(contentsOf: xmlURL)!
xmlParser.delegate = self
let success = xmlParser.parse()
if success {
print("parse success!")
print(currentElement)
} else {
print("parse failure!")
}
}
//MARK: XMLParserDelegate methods
func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {
currentElement = elementName
if elementName == "StationDesc"
|| elementName == "StationLatitude"
|| elementName == "StationLongitude"
|| elementName == "StationCode"
|| elementName == "StationId"
{
if elementName == "StationDesc" {
passName = true
}
passData = true
}
}
func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
currentElement = ""
if elementName == "StationDesc"
|| elementName == "StationLatitude"
|| elementName == "StationLongitude"
|| elementName == "StationCode"
|| elementName == "StationId"
{
if elementName == "StationDesc" {
passName = false
}
passData = false
}
}
func parser(_ parser: XMLParser, foundCharacters string: String) {
if passName {
strXMLData = strXMLData+"\n\n"+string
}
if passData {
//ready content for codable struct
switch currentElement {
case "StationDesc":
station = string
case "StationLatitude":
latitude = string
case "StationLongitude":
longitude = string
case "StationCode":
code = string
case "StationId":
id = string
print(string)
default:
id = string
}
}
}
func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
print("failure error: ", parseError)
}
}
The XMLParser just needs to be held while parse() is running, so you have no need to declare xmlParser as a property of XMLParserHelper.

Answer 2

You need a strong reference
class ViewController: UIViewController{
var parser:XMLParserHelper!
override func viewDidLoad() {
super.viewDidLoad()
parser = XMLParserHelper()
parser.runParser()
}
}