I tried the completion handler as suggested by Gurdev and got something. It does return the values of my array in the MAIN function. But the issue is the same: I have to use Sleep() function for 3 seconds for the HTTP request to complete. This is like hard coding as it could take less or more than 3 seconds to complete. When I remove the Sleep() command, I end up returning a VOID array.
The relevant code is pated below.
Thanks!
--------Web Class--------
import Foundation
import UIKit
class Web {
var ar1 = [Double]()
var ar2 = [Double]()
func getData(str: String, completion: (_ result: [[Double]]) -> Void) {
let request = NSMutableURLRequest(url: URL(string: str)!)
httpGet(request as URLRequest!){
(data, error) -> Void in
if error != nil {
print(error ?? "Error")
} else {
let delimiter = "\t"
let lines:[String] = data.components(separatedBy: CharacterSet.newlines) as [String]
for line in lines {
var values:[String] = []
if line != "" {
values = line.components(separatedBy: delimiter)
let str1 = (values[0])//FIRST COLUMN
let str2 = (values[1])//SECOND COLUMN
let db1 = NumberFormatter().number(from: str1)?.doubleValue
self.ar1.append(db1!)
let db2 = NumberFormatter().number(from: str2)?.doubleValue
self.ar2.append(db2!)
}
}
}
}//end of request
sleep(3) // This delay sends data to MAIN, Otherwise NOT
let dta = [self.ar1, self.ar2]
completion(dta)
}
func httpGet(_ request: URLRequest!, callback: @escaping (String, String?) -> Void) {
let session = URLSession.shared
let task = session.dataTask(with: request, completionHandler: {
(data, response, error) -> Void in
if error != nil {
callback("", error!.localizedDescription)
} else {
let result = NSString(data: data!, encoding:
String.Encoding.ascii.rawValue)!
callback(result as String, nil)
}
})
task.resume()
}
} --------Web Class--------
-------Call In Class--------
Web().getData (str: "https://dl.dropboxusercontent.com/s/f6j7w7zeqaavzqw/s02.txt?dl=0")
{
(result: [[Double]]) in
let x = result[0]
let y = result[1]
}
-------Call In Class--------
Essentially, I am trying to access my variable "ar1" at a certain point in my code but I cannot. I am trying to return the value too but it returns NULL at that point.
What is wrong here ?
I tried like the below code :
import Foundation
import UIKit
class Web {
var ar1 = [Double]()
var ar2 = [Double]()
func getData(str: String) -> [Double] {
let request = NSMutableURLRequest(url: URL(string: str)!)
httpGet(request as URLRequest!){
(data, error) -> Void in
if error != nil {
print(error ?? "Error")
} else {
let delimiter = "\t"
let lines:[String] = data.components(separatedBy: CharacterSet.newlines) as [String]
for line in lines {
var values:[String] = []
if line != "" {
values = line.components(separatedBy: delimiter)
let str1 = (values[0])//FIRST COLUMN
let str2 = (values[1])//SECOND COLUMN
let db1 = NumberFormatter().number(from: str1)?.doubleValue
self.ar1.append(db1!)
let db2 = NumberFormatter().number(from: str2)?.doubleValue
self.ar2.append(db2!)
}
}
dump (self.ar1) // "ar1" accessible HERE (returns all elements)
}
}//end of request
//BUT I WANT TO RETURN "ar1" HERE !
// So that I can use it in my MAIN class
dump (self.ar1) // "ar1" not accessible here (returns ZERO elements)
return self.ar1
}
func httpGet(_ request: URLRequest!, callback: @escaping (String, String?) -> Void) {
let session = URLSession.shared
let task = session.dataTask(with: request, completionHandler: {
(data, response, error) -> Void in
if error != nil {
callback("", error!.localizedDescription)
} else {
let result = NSString(data: data!, encoding:
String.Encoding.ascii.rawValue)!
callback(result as String, nil)
}
})
task.resume()
}
}