Returning a variable outside closure - ios

Question

I want to check the number of posts in my database and return it as the numberOfRows in my tableView. However, the below code does not work. It returns 1 everytime. I know it's because I'm setting the var requestPostCount inside a closure, but I'm not sure on how to fix it.
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
var requestPostcount: Int = 1
if segmentOutlet.selectedSegmentIndex == 0 {
// This is temporary
return 1
}
else {
// Query the database to check how many posts are there
ref.child("Request Posts").observe(.value, with: { (snapshot) in
var requestPostCount = Int(snapshot.childrenCount)
// If database is empty, only 1 row is needed to display error message
if requestPostCount == 0 {
requestPostCount = 1
}
})
}
return requestPostcount
}

Answer 1

numberOfRowsInSection is the wrong place to be querying your database.
At any rate, the method will return requestPostcount with your default value before the closure finishes executing.
You need to find a better place to query your database so that when numberOfSections is called, the data is already available.

Answer 2

You misunderstand how async methods work. You can't do an async query of a remote database in your numberOfRows method and return a value.
It's not possible to have a function that calls an async method return the results of the async method as a function result.
You need to set up your model to have no data in it, send the database query, parse the results, and then, in the completion closure, update your model and then, on the main thread, tell the table view to update.

Answer 3

You need to load data in ViewDidLoad . after getting data then reload tableview,
var requestPostcount: Int = 1 // declared variable
override func viewDidLoad() {
super.viewDidLoad()
ref.child("Request Posts").observe(.value, with: { (snapshot) in
var requestPostCount = Int(snapshot.childrenCount)
// If database is empty, only 1 row is needed to display error message
if requestPostCount == 0 {
requestPostCount = 1
}
tblView.reloadData()
})
}
Now numberOfRowsInSection as below
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if segmentOutlet.selectedSegmentIndex == 0 {
return 1
}
else {
return requestPostcount
}