Retrieving data back from server side based on input - ios

Question

I'm doing a school project, its's multiple tables and tabBarControllers. Now, I want to display return data back from server side based on selected row. I managed to pass selected row from View to another, and I believe there is nothing wrong with passing it to the server side, too. The problem is when retrieving the data back from the server.
Here is Course View
// This array is to hold data coming from server side
var course: NSArray = []
// Assign data that come from DepartmentView
public var department: String? = nil
var myURL = URL(string: "http://localhost/masterProject/scripts/courses.php")
override func viewDidLoad()
{
super.viewDidLoad()
self.title = "Courses"
}
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
// This is just to make sure it gets data and not nil
let vDepartment = department!
// Create a request
var request = URLRequest(url: myURL!)
request.httpMethod = "POST";
// Create a parameter to be sent to server side and based on this
// data I want to get data back that belong to it.
let postParameter = "department=\(vDepartment)";
request.httpBody = postParameter.data(using: String.Encoding.utf8)
// Here I Create and send dataTask
let task = URLSession.shared.dataTask(with: request)
{ (data: Data?, response: URLResponse?, error: Error?) in
DispatchQueue.main.async
{
if(error != nil)
{
self.alertMessage(message: (error?.localizedDescription)!)
return
}
// This is supposed to read data from server side and display it
// in Course table view.
self.course = try! JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! NSArray
}
}
task.resume()
}
// MARK: - Table view data source
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return course.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "courseCell", for: indexPath) as! CourseTableViewCell
let main = course[indexPath.row] as! NSDictionary
cell.courseName.text = (main["name"] as! String)
cell.courseNumber.text = (main["number"] as! String)
return cell
}
func alertMessage(message: String)
{
let alert = UIAlertController(title: "Alert", message: message, preferredStyle: .alert)
let action = UIAlertAction(title: "Ok", style: .default, handler: nil)
alert.addAction(action)
self.present(alert, animated: true, completion: nil)
}
Department view
var departments: NSArray = []
var myURL = URL(string: "http://localhost/masterProject/scripts/department.php")
override func viewDidLoad()
{
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool)
{
self.title = "Departments"
super.viewWillAppear(animated)
let data = NSData(contentsOf: myURL!)
departments = try! JSONSerialization.jsonObject(with: data! as Data, options: .mutableContainers) as! NSArray
}
// MARK: - Table view data source
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
// #warning Incomplete implementation, return the number of rows
return departments.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
let data = departments[indexPath.row] as! NSDictionary
cell.textLabel?.text = (data["name"] as! String)
return cell
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
{
if segue.identifier == "showDepCourses"
{
if let indexPath = tableView.indexPathForSelectedRow
{
let courseVC = segue.destination as! CourseTableViewController
let data = departments[indexPath.row] as! NSDictionary
courseVC.department = (data["name"] as! String)
}
}
}
}
Here are the picture for both Views
department view
course view
I'm supposed get the right data based on selected row but instead it shows nothing.

Answer 1

self.tabeView.reloadData() was missing the whole time.
This is the answer for the question:
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
// Just to make sure "Optional" keyword not send as POST PERAMETER
let selectedDep = department!
// Create a request
var request = URLRequest(url: myURL!)
request.httpMethod = "POST";
// Create a parameter to be sent to server side and based on this
// data I want to get data back that belong to it.
let postParameter = "department=\(selectedDep)";
request.httpBody = postParameter.data(using: String.Encoding.utf8)
// Here I create and send dataTask
let task = URLSession.shared.dataTask(with: request)
{ (data: Data?, response: URLResponse?, error: Error?) in
DispatchQueue.main.async
{
if(error != nil)
{
self.alertMessage(message: (error?.localizedDescription)!)
return
}
// This is supposed to read data from server side and display it
// in Course table view.
self.courses = try! JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! NSArray
self.tableView.reloadData()
}
}
task.resume()
}