can't populate custom tableview header swift 3: index out of range - ios

Question

My app has a user account page that uses a tableview to return a timeline type detail. I'd like to have the actual logged-in user detail at the top in a table header.
This is handled on the useraccountViewController. I have added a function to the viewDidLoad called getUserAndTimeLine() which makes 2 api calls to my web-service to get the details for my logged in user (this view controller is opened by a segue from the login page).
I also have 2 structs one for the loggedUser, and one for the userPost that define what I am expecting to receive from the API calls. I also have arrays for the user and the posts based on the structs.
The getUserAndTimeLine() code is as follows:
//creates api url to get user
let url = URL(string: "myapi.url/getuser?uid=" + user)
//httpget sent to the api and listens for response
URLSession.shared.dataTask(with:url!) { (data, response, error) in
if error != nil {
print(error as Any)
}
else {
do{
//parses the json data
let parsedData = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary
//get the user data
let thisUser = parsedData["userName"] as? String
let thisUserImage = parsedData["userAvatar"] as? String
let thisLoggedUser = loggedUser( userAvatar: thisUserImage, userName: thisUser)
self.arrayOfLoggedUser.append(thisLoggedUser)
}
catch{
print("parse error")
}
}
}.resume()
//creates api url to get user TL
let tlurl = URL(string: "myapi.url?uid=" + user)
//httpget sent to the api and listens for response
URLSession.shared.dataTask(with:tlurl!) { (data, response, error) in
if error != nil {
print(error as Any)
}
else {
do{
//parses the json data
let parsedTLData = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! [String:AnyObject]
guard let posts = parsedTLData["timeline"] as? [[String:AnyObject]] else {return}
for post in posts {
let thisPost = postData(postText: post["postText"] as! String, postURL: post["postURL"] as! String, postImageURL: post["postImage"] as! String,
postDomainName: post["postSource"] as! String,
postDomainLink: post["postDomainLink"] as! String,
postPoster: post["postPoster"] as! String,
postPosterAvatar: post["postPosterAvatar"] as! String,
postDate: post["postCreateDate"] as! String)
self.arrayOfPostData.append(thisPost)
self.tableView.reloadData() }
}
catch{
print("parse error")
}
}
}.resume()
In the individual cells, I am successfully able to populate my tableview (timeline) with the data from arrayOfPostData via:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = Bundle.main.loadNibNamed("postTimeLineCell", owner: self, options: nil)?.first as! postTimeLineCell
cell.postImage.sd_setImage(with: URL(string: arrayOfPostData[indexPath.row].postImageURL))
cell.postText.setTitle(arrayOfPost[indexPath.row].postText, for:.normal )
cell.postDate.text = arrayOfPostData[indexPath.row].postDate
// etc.
return cell
}
However I cannot return the header:
override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let loggedUserHeader = Bundle.main.loadNibNamed("userHeader", owner: self, options: nil)?.first as! userHeader
loggedUserHeader.userName.text = arrayOfLoggedUser[section].userName
return loggedUserHeader
}
as I get an error: EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0) which in the output is "fatal error: Index out of range"
Can anyone help out as I'm rather stuck!

Answer 1

Asynchronous data is almost always the problem.
The user array will be populated after the API call has completed - but you will be refreshing the tableView before that.
Simplest thing is to put a check in viewForHeaderInSection and if the array.count < section index then just return with nothing, or a default value