Array of structs: UserDefaults, how to use? - swift

Question

I've already check all of those topics:
How to save an array of custom struct to NSUserDefault with swift?
How to save struct to NSUserDefaults in Swift 2.0
STRUCT Array To UserDefaults
I have a struct containing some Strings and an other struct: MySection.
struct MySection {
var name: String = ""
var values: [MyRow] = []
}
And there is MyRow which is store in MySection.values
struct MyRow {
var value: String = ""
var quantity: String = ""
var quantityType: String = ""
var done: String = ""
}
Two arrays for use it
var arraySection: [MySection] = []
var arrayRow: [MyRow] = []
And in my application, I add dynamically some values in those arrays.
There is the delegate method for get datas from my second ViewController
func returnInfos(newItem: [MyRow], sectionPick: String) {
arrayRow.append(MyRow())
arrayRow[arrayRow.count - 1] = newItem[0]
manageSection(item: sectionPick)
listTableView.reloadData()
}
And there is the manageSection function.
func manageSection(item: String) {
var i = 0
for _ in arraySection {
if arraySection[i].name == item {
arraySection.insert(MySection(), at: i + 1)
arraySection[i + 1].values = [arrayRow[arrayRow.count - 1]]
return
}
i += 1
}
arraySection.append(MySection())
arraySection[arraySection.count - 1].name = item
arraySection[arraySection.count - 1].values = [arrayRow[arrayRow.count - 1]]
}
My need is to store datas of the two arrays in UserDefaults (or CoreData maybe??) and use these datas when the user going back to the application.
I don't know how to do it, I've already try methods from the 3 topics but I'm not even doing a good job.
How can I do it?
Thanks guys!

Answer 1

Since both types contain only property list compliant types a suitable solution is to add code to convert each type to a property list compliant object and vice versa.
struct MySection {
var name: String
var values = [MyRow]()
init(name : String, values : [MyRow] = []) {
self.name = name
self.values = values
}
init(propertyList: [String: Any]) {
self.name = propertyList["name"] as! String
self.values = (propertyList["values"] as! [[String:String]]).map{ MyRow(propertyList: $0) }
}
var propertyListRepresentation : [String: Any] {
return ["name" : name, "values" : values.map { $0.propertyListRepresentation }]
}
}
struct MyRow {
var value: String
var quantity: String
var quantityType: String
var done: String
init(value : String, quantity: String, quantityType: String, done: String) {
self.value = value
self.quantity = quantity
self.quantityType = quantityType
self.done = done
}
init(propertyList: [String:String]) {
self.value = propertyList["value"]!
self.quantity = propertyList["quantity"]!
self.quantityType = propertyList["quantityType"]!
self.done = propertyList["done"]!
}
var propertyListRepresentation : [String: Any] {
return ["value" : value, "quantity" : quantity, "quantityType" : quantityType, "done" : done ]
}
}
After creating a few objects
let row1 = MyRow(value: "Foo", quantity: "10", quantityType: "Foo", done: "Yes")
let row2 = MyRow(value: "Bar", quantity: "10", quantityType: "Bar", done: "No")
let section = MySection(name: "Baz", values: [row1, row2])
call propertyListRepresentation to get a dictionary ([String:Any]) which can be saved to User Defaults.
let propertyList = section.propertyListRepresentation
Recreation of the section is quite easy, too
let newSection = MySection(propertyList: propertyList)
Edit
Use the propertyList initializer only if you get data from UserDefaults in all other cases use the other initializer.
For example replace
#IBAction func addButtonPressed(_ sender: Any) {
newProducts.append(MyRow(propertyList: ["":""]))
newProducts[newProducts.count - 1].value = nameTextField.text!
newProducts[newProducts.count - 1].quantity = quantityTextField.text!
newProducts[newProducts.count - 1].quantityType = type
newProducts[newProducts.count - 1].done = "No"
delegate?.returnInfos(newItem: newProducts, sectionPick: typePick)
navigationController?.popViewController(animated: true)
}
with
#IBAction func addButtonPressed(_ sender: Any) {
let row = MyRow(value: nameTextField.text!,
quantity: quantityTextField.text!,
quantityType: type,
done: "No")
newProducts.append(row)
delegate?.returnInfos(newItem: newProducts, sectionPick: typePick)
navigationController?.popViewController(animated: true)
}
and replace
func returnInfos(newItem: [MyRow], sectionPick: String) {
arrayRow.append(MyRow(propertyList: ["":""]))
arrayRow[arrayRow.count - 1] = newItem[0]
manageSection(item: sectionPick)
listTableView.reloadData()
}
with
func returnInfos(newItem: [MyRow], sectionPick: String) {
arrayRow.append(newItem[0])
manageSection(item: sectionPick)
listTableView.reloadData()
}
Basically first create the object, then append it to the array. The other way round is very cumbersome.