Display UIActivityIndicator while loading API data safely - ios

Question

I'm working on this app and have developed a full API for it. However, now that I've come to the front end part (the IOS app), I'm not sure how to load that data the right way.
I have made this class to make requests a little bit easier, but I get confused when it comes to threading and that sort of stuff...
Basically, I have a simple UITableView set up, and I want it to display data that I fetch from my API. During fetching, I need it to display a UIActivityIndicator which has to hide automatically as well.
How the hell do I do this? (Especially the automatic UIActivityIndicator)
Here is my request struct:
//
// Request.swift
// Voots
//
// Created by Carlo on 16/10/2017.
// Copyright © 2017 Carlo. All rights reserved.
//
import Foundation
struct Request {
// Post request with specific url, parameters and token
func post(params: [String: String], url: String, token: String?,
completion: ((Data, URLResponse) -> ())?) {
let nsUrl = NSURL(string: url)
var request = URLRequest(url: nsUrl! as URL)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// If a token was provided, add it.
if token != nil {
request.addValue("Bearer \(String(describing: token!))", forHTTPHeaderField: "Authorization")
print(request.value(forHTTPHeaderField: "Authorization")!)
}
request.httpMethod = "POST"
guard let httpBody = try? JSONSerialization.data(withJSONObject: params, options: JSONSerialization.WritingOptions.prettyPrinted) else {
return
}
request.httpBody = httpBody
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let data = data {
if let response = response {
if completion != nil {
completion!(data, response)
}
}
}
}.resume()
}
func get(url: String, token: String?, completion: ((Data, URLResponse) -> ())?) {
let nsUrl = NSURL(string: url)
var request = URLRequest(url: nsUrl! as URL)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// If a token was provided, add it.
if token != nil {
request.addValue("Bearer \(String(describing: token!))", forHTTPHeaderField: "Authorization")
print(request.value(forHTTPHeaderField: "Authorization")!)
}
request.httpMethod = "GET"
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let data = data {
if let response = response {
if completion != nil {
completion!(data, response)
}
}
}
}.resume()
}
}

Answer 1

Here is list of readymade (available) libraries, if you don't want to add manual effort to manage this:
iOS Libraries - ActivityIndicatorView
MBProgressHUD
SVProgressHUD
Here is sample for you, how you can manage it.
class ViewController: UIViewController {
// Create an IBOutlet of indicator or you can create it programatically also.
#IBOutlet weak var activitIndicator: UIActivityIndicatorView!
override func viewDidLoad() {
super.viewDidLoad()
activitIndicator.isHidden = false
Request.post(params: <#T##[String : String]#>, url: <#T##String#>, token: <#T##String?#>) { (<#Data#>, <#URLResponse#>) in
DispatchQueue.main.async(execute: {
self.activitIndicator.isHidden = true
})
}
}
}
struct Request {
// Post request with specific url, parameters and token
// Note: use static function
static func post(params: [String: String], url: String, token: String?,
completion: ((Data, URLResponse) -> ())?) {
let nsUrl = NSURL(string: url)
var request = URLRequest(url: nsUrl! as URL)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// If a token was provided, add it.
if token != nil {
request.addValue("Bearer \(String(describing: token!))", forHTTPHeaderField: "Authorization")
print(request.value(forHTTPHeaderField: "Authorization")!)
}
request.httpMethod = "POST"
guard let httpBody = try? JSONSerialization.data(withJSONObject: params, options: JSONSerialization.WritingOptions.prettyPrinted) else {
return
}
request.httpBody = httpBody
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let data = data {
if let response = response {
if completion != nil {
completion!(data, response)
}
}
}
}.resume()
}
// Note: use static function
static func get(url: String, token: String?, completion: ((Data, URLResponse) -> ())?) {
let nsUrl = NSURL(string: url)
var request = URLRequest(url: nsUrl! as URL)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// If a token was provided, add it.
if token != nil {
request.addValue("Bearer \(String(describing: token!))", forHTTPHeaderField: "Authorization")
print(request.value(forHTTPHeaderField: "Authorization")!)
}
request.httpMethod = "GET"
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let data = data {
if let response = response {
if completion != nil {
completion!(data, response)
}
}
}
}.resume()
}
}