text file content issue - ios

Question

So, I'm making an importing system to bring text files from email into the app to read there contents. I am very new to swift, and app programming at that (mainly do backend), and I am having an issue with the code below. It is most likely very inefficient and there is probably a better way to do this, but currently I have the func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool with some other code to assign variables to the URL to send to the view controller (haven't worked with notifications/rootviewcontrollers yet). however, after running this code, the result, instead of the contents of the file, is ("matrixFile4197009889-26.text", Unicode (UTF-8)). What should I do? Please explain in "baby language."
My view controller code:
let delegate = UIApplication.shared.delegate as! AppDelegate
if delegate.importFileIndicator == true {
let filemgr = FileManager.default
let docsDirURL = try! filemgr.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
let inboxURL = docsDirURL.appendingPathComponent("Inbox")
print(inboxURL)
do{
var directoryContents = try FileManager.default.contentsOfDirectory(at: inboxURL, includingPropertiesForKeys: nil, options: [])
var fileSearchBoolCounter = false
var fileSearchCounter = 0
var fileURL: URL
while fileSearchBoolCounter == false {
if (String(describing: directoryContents[fileSearchCounter].lastPathComponent).range(of: String(describing: NSURL(string: delegate.urlString)!.lastPathComponent!)) != nil) {
fileURL = directoryContents[fileSearchCounter]
fileSearchBoolCounter = true
print(fileURL)
let path = inboxURL.appendingPathComponent((NSURL(string: delegate.urlString)?.lastPathComponent!)!)
encryptedMessageField.text = try String(contentsOfFile: String(describing: path), encoding: String.Encoding.utf8)
}else{
print(directoryContents[fileSearchCounter])
fileSearchCounter += 1
print(NSURL(string: delegate.urlString)!.lastPathComponent!)
}
}
delegate.importFileIndicator = false
fileSearchBoolCounter = false
fileSearchCounter = 0
}catch let error as NSError{
print(error)
}
}
My AppDelegate code:
var importFileIndicator = false
var urlString = ""
func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
urlString = String(describing: url)
print(urlString)
importFileIndicator = true
return true
}

Answer 1

I think you've already good with some parts, but I'm going to include them too in the whole process.
1. Make your app available to open a TXT file
To let the system know that your app is prepared to receive a TXT file, you need to configure the Info.plist itself, or the simplest way is to configure via TARGETS/"Info tab"/"Document Types section":
At this point your app becomes available to handle the TXT files coming from other external applications. So when you're about to open a TXT file that is attached to a mail, you should see your app available in the list:
2. Prepare app to receive incoming TXT file
In order to handle the supported file type, you need to implement the application:openURL:options: method you've already mentioned in your AppDelegate. Here you receive the file path as url, that you can easily send towards your ViewController for further processing. This url should looks something like this:
(lldb) po url
▿ file:///private/var/mobile/Containers/Data/Application/42D78E58-C7EC-4F3B-9100-B731AF7A4E45/Documents/Inbox/sample.txt
3. Handle the TXT file
Here you can also store the file's content in a String using the appropriate String initializer.
String(contentsOf: url, encoding: String.Encoding.utf8)
and then you can pass that String to your ViewController.
So your application:openURL:options: in your AppDelegate should looks something like this (depends on your actual view controller hierarchy) :
func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
do {
let contentString = try String(contentsOf: url, encoding: .utf8)
if let window = self.window, let viewController = window.rootViewController as? ViewController {
viewController.displayText(text: contentString)
// here you pass the actual content as String to your custom ViewController which implements a displayText: function that receives a string
}
}
catch {
// contents could not be loaded
}
return true
}