How to add elements to a realm database - swift

Question

I am working on a simple app that catalogues information. Right now I am just trying to collect information and then add it to a realm database. Unfortunately I cannot figure it out and no matter what method I try (based on tutorials and the Realm website) I get the error "Use of unresolved identifier 'realm'.
This is the code based on the command button executing the command.
#IBAction func Submit(_ sender: Any) {
let myList = WineList()
myList.vinyard = Vinyard.text
myList.type = typeField.text
myList.name = Name.text
myList.grape = Grape.text
myList.year = Year.text
myList.price = Price.text
myList.rating = rateField.text
myList.purchased = purch
myList.notes = Notes.text
//from realm website example
try! realm.write{
realm.add(myList)
}
//from tutorials
//realm.beginWrite()
//realm.add(myList)
//try realm.commitWrite()
}
Can anyone please advise me on what I am doing wrong? I will post all of my code below.
import UIKit
import RealmSwift
class RankViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var purch = ""
#IBOutlet weak var typeField : UITextField!
#IBOutlet weak var rateField : UITextField!
#IBOutlet weak var Vinyard: UITextField!
#IBOutlet weak var Name: UITextField!
#IBOutlet weak var Grape: UITextField!
#IBOutlet weak var Year: UITextField!
#IBOutlet weak var Price: UITextField!
#IBOutlet weak var Notes: UITextField!
#IBAction func Purchased(_ sender: UISwitch) {
if (sender.isOn == true){
purch = "Yes"
}
else {
purch = "No"
}
}
let wineTypes = ["Red","White","Rose","Sparkling","Ice - Red","Ice - White", "Port","Fruit","Other"]
let wineRate = ["Hurray", "Meh", "Boo"]
var typeView = UIPickerView()
var rateView = UIPickerView()
override func viewDidLoad() {
super.viewDidLoad()
let realm = try! Realm()
print (Realm.Configuration.defaultConfiguration.fileURL)
typeView.delegate = self
typeView.dataSource = self
rateView.delegate = self
rateView.dataSource = self
Vinyard.delegate = self
Name.delegate = self
Grape.delegate = self
Year.delegate = self
Price.delegate = self
Notes.delegate = self
typeField.inputView = typeView
rateField.inputView = rateView
}
public func numberOfComponents(in pickerView: UIPickerView) -> Int {
if pickerView == typeView {
// Returns for typeView
return 1
}
else if pickerView == rateView {
// Returns for rateView
return 1
}
return 1
}
public func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if pickerView == typeView {
// Returns for typeView
return wineTypes.count
}
else if pickerView == rateView {
// Returns for rateView
return wineRate.count
}
return wineRate.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if pickerView == typeView {
// Returns for typeView
return wineTypes[row]
}
else if pickerView == rateView {
// Returns for rateView
return wineRate[row]
}
return wineRate[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
if pickerView == typeView {
// Do stuff for typeView
typeField.text = wineTypes[row]
typeField.resignFirstResponder()
}
else if pickerView == rateView {
// Do stuff for rateView
typeField.text = wineRate[row]
typeField.resignFirstResponder()
}
}
#IBAction func Submit(_ sender: Any) {
let myList = WineList()
myList.vinyard = Vinyard.text
myList.type = typeField.text
myList.name = Name.text
myList.grape = Grape.text
myList.year = Year.text
myList.price = Price.text
myList.rating = rateField.text
myList.purchased = purch
myList.notes = Notes.text
//from realm website example
try! realm.write{
realm.add(myList)
}
//from tutorials
//realm.beginWrite()
//realm.add(myList)
//try realm.commitWrite()
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
Year.resignFirstResponder()
Price.resignFirstResponder()
}
}
extension RankViewController : UITextFieldDelegate{
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
}
Separate file
import Foundation
import RealmSwift
class WineList: Object {
#objc dynamic var vinyard: String?
#objc dynamic var name: String?
#objc dynamic var grape: String?
#objc dynamic var year: String?
#objc dynamic var price: String?
#objc dynamic var notes: String?
#objc dynamic var type: String?
#objc dynamic var rating: String?
#objc dynamic var purchased: String?
}

Answer 1

Variables only exist with the function or class they are created. So take these two functions
func getData() {
let realm = Realm()
let results = realm.objects...
}
and
func printData() {
print(results) //this won't work
}
as you can see, the var 'realm' is instantiated in getData so that var is only available within that function and would not be available within the printData function.
In your case you've instantiated the realm var within viewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
let realm = try! Realm()
therefore it will only be available within the viewDidLoad function.
To correct your issue, you need to instantiate realm within the function where you're trying to use it
#IBAction func Submit(_ sender: Any) {
let myList = WineList()
...
let realm = try! Realm()
try! realm.write{
realm.add(myList)
}
to expand on that a bit. Take your RankViewController class
class RankViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var purch = ""
See the 'purch' var? That's called a 'class var' and because it's defined at a high level within the class, it would be available throughout the class.
func printData() {
print(self.purch) //this will work
}
note that I preceded purch with self. when I referenced it. To me, that's a good indicator it's a class var and makes the code more readable. However, it's not required.