How can I get variable to text from php to swift app - swift

Question

I use this code and work perfect. I use swift. PHP is work fine.
I also try some other examples at this
I have 2 problems
first my responseString values turns in Optional("Success"). Why?
second is How can assign it on my button?
func makePostCall() {
var request = URLRequest(url: URL(string: "MyURL/page.php")!)
request.httpMethod = "POST"
let postString = "id=login"
request.httpBody = postString.data(using: .utf8)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else { // check for fundamental networking error
print("error=\(error)")
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(response)")
}
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(responseString)")
self.lbl.text = responseString
}
task.resume()
//return responseString
}

Answer 1

You need to use DispatchQueue.main.async to work with UI from URLRequests. Also you need to use [weak self] to prevent reference cycle problem. At last, btn.setTitle(responseString, for: .normal) to set title for button state .normal. Here is correct answer!
func makePostCall() {
var request = URLRequest(url: URL(string: "MyURL/page.php")!)
request.httpMethod = "POST"
let postString = "id=login"
request.httpBody = postString.data(using: .utf8)
let task = URLSession.shared.dataTask(with: request) {[weak self] data, response, error in
guard let data = data, error == nil else { // check for fundamental networking error
print("error=\(error)")
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(response)")
}
guard let responseString = String(data: data, encoding: .utf8) else {
return
}
print("responseString = \(responseString)")
DispatchQueue.main.async {
self?.lbl.text = responseString
self?.btn.setTitle(responseString, for: .normal) // your button
}
}
task.resume()
//return responseString
}