Get JSON data and display in tableview Xcode - ios

Question

I'm creating a IOS program to download json data from url and display in table view of ios. i have issue to download JSON (every 10 second )in loginpage view controller and parse JSON data to tableview controller. Before posting this, i have try to search many times but can't find solution. Below is StoryBoad and the code
Story Board
User will login, after login success, JSON data will be loaded (userlogin = true). Below code in login class loginPage: UIViewController
#IBOutlet weak var usernameLogin: UITextField!
#IBOutlet weak var passwordLogin: UITextField!
#IBAction func loginPress(_ sender: Any) {
username = usernameLogin.text!
password = passwordLogin.text!
let request = NSMutableURLRequest(url: NSURL(string: "http://talectric.com/wp-admin/a_p/users/userlogin.php")! as URL)
request.httpMethod = "POST"
let postString = "username=\(username)&password=\(password)"
request.httpBody = postString.data(using: String.Encoding.utf8)
let task = URLSession.shared.dataTask(with: request as URLRequest) {
data, response, error in
if error != nil {
print("error=\(error!)")
return
}
else
{
do {
let respondString = try JSONSerialization.jsonObject(with: data!, options: []) as? NSDictionary
print(respondString!)
let message = respondString?["message"] as! String
if message == "Check Pass" {
userlogin = true
DispatchQueue.main.async {
let TabViewPageController = self.storyboard?.instantiateViewController(withIdentifier: "TabViewPageID") as! TabViewPage
self.present(TabViewPageController, animated: true, completion: nil)
}
}
else {
DispatchQueue.main.async {
let alertController = UIAlertController(title: "Login", message:
"Username or Password is not correct", preferredStyle: UIAlertController.Style.alert)
alertController.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default,handler: nil))
self.present(alertController, animated: true, completion: nil)
}
}
}
catch let error as NSError {
print(error.debugDescription)
}
}
}
task.resume()
}
after userlogin = true, #objc func taskdo() will load JSON data to nodeidArray but second download not overwrite first element of nodeidArray and nodeidArray is inserted after last element ( i just want nodeidArray to be overwrited)
import UIKit
var timer = Timer()
var userlogin = false
struct Data {}
var username = String()
var password = String()
class loginPage: UIViewController{
var nodeidArray = [String]()
override func viewDidLoad() {
super.viewDidLoad()
timerstart()
}
func timerstart()
{
timer = Timer.scheduledTimer(timeInterval: 5, target: self,selector: #selector(loginPage.taskdo),userInfo:nil,repeats: true)
}
#objc func taskdo()
{
if userlogin == true{
let request = NSMutableURLRequest(url: NSURL(string: "http://talectric.com/wp-admin/a_p/iot/read_all.php")! as URL)
request.httpMethod = "POST"
let postString = "username=\(username)&password=\(password)&authen=wdwfesf9329140dsvfxkciospdkm"
request.httpBody = postString.data(using: String.Encoding.utf8)
let task = URLSession.shared.dataTask(with: request as URLRequest) {
data, response, error in
if error != nil {
print("error=\(error!)")
return
}
else
{
do {
if let respondString = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {
if let nodedata = respondString.value(forKey: "nodedata") as? NSArray {
for node in nodedata{
if let nodeDict = node as? NSDictionary {
if let nodeid = nodeDict.value(forKey: "nodeid"){
self.nodeidArray.insert(nodeid as! String, at: 0)
}
}
}
}
}
// print(respondString!)
//let message = respondString?["numberofnodeid"] as! Int
//let nodedata = respondString!.value(forKey: "nodedata")//
// let nodeid = (nodedata as AnyObject).value(forKey: "nodeid")
// print(respondString!.value(forKey: "nodedata")!)
print(self.nodeidArray)
let defaults = UserDefaults.standard
defaults.set(self.nodeidArray, forKey: "YourKey")
}
catch let error as NSError {
print(error.debugDescription)
}
}
}
task.resume()
}
}
}
After download JSON in LoginViewController, i can not paste data to tableview controller. I have try to change nodeidArray to static in LoginPage but can't use static variable in #objc func taskdo(). I try UserDefaults also but can't get data in TableViewController (NodeDataPage)
i have test tableview success with Local Variable in Class NodeDataPage but can't test variable from other viewcontroller
import UIKit
class NodeDataPage:
UIViewController,UITableViewDelegate,UITableViewDataSource {
//var nodeidname = ["nodeid1","nodeid2","nodeid3"]
var testArray : [String]() = UserDefaults.standard.objectForKey("YourKey") {
var nodeidname : [NSString] = testArray! as! [NSString]
println(readArray)
}
#IBOutlet weak var tableView: UITableView!
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return nodeidname.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier:"nodeCell",for: indexPath)
cell.textLabel?.text = nodeidname[indexPath.row]
return cell
}}
I specify the questions:
How can i transfer JSON data (download in LoginPage VC) to Table View VC (NodeDataPage VC) ?
How can i run JSON download function in LoginPage VC every 10s with Question 1 also (i try static variable to get in other view and can't run in #objc func taskdo() ?
I want to run JSON download data every 10s after userlogin. Should i put this function in LoginPage VC or other view because i need to get data from server continuously ?
How can i run JSON download func when the app is hidden (not be killed) ?
i have tried to research small part but now it become more complicated. Please help me.
Thank you

Answer 1

Create a separate class like "DataManager" which holds all your data (nodeidArray) as well as makes calls to server to fetch from web service every 10 seconds.
Once user logs in successfully, show the NodeDataPage. In viewDidLoad of this class, create DataManager object and call the method that handles the timer and fetching data from server.
Use notification or observer design pattern to intimate the NodeDataPage to get the data from DataManager and reload the tableview.
Hope I am able to answer your questions.