UserDefaults array is coming back empty

Question

Im trying to set an array of objects to user defaults but is not appending.

declaring the var for the array in my AllFormulas Class:

let defaults = UserDefaults.standard    
static var lineOne1 = UserDefaults.standard.array(forKey: "line1") as? [Formulas] ?? []
init() {
//formula names and values

then im starting with an empty array

lineOne1 = []
}

appending to the array in my AddViewController Class :

 func lineOneAdd() {
    let line1 = lineOne1
    lineOne1.append(formulaAppend)
    defaults.set(line1, forKey: "line1")
    defaults.synchronize()

}

then calling the userDefaults in view did load in MainViewController Class:

line1[indexPath.row] // as my cellForRowAt in tableView


print(line1)
//which prints : []

any idea what im doing wrong? thanks in advance

And the call to `synchronize` is obsolete. It should be removed. — rmaddy, Jun 05 '19 at 03:36
Are the userDefaults global? when im calling on forKey: "line1" , my lineOne1 variable is declared in another class. would that matter? — Mark Rogers, Jun 05 '19 at 03:55
yeah, sorry.. Im just trying to simplify it for ease. I didn't specify, thats on me — Mark Rogers, Jun 05 '19 at 04:07

score 1 · Answer 1 · answered Jun 05 '19 at 03:20

1

You seem to be appending to the wrong array:

lineOne1.append(formulaAppend)

Should be:

line1.append(formulaAppend)

answered Jun 05 '19 at 03:20

jake

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14

I tried that. but this is what happens when i call that function "*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object ( "MyProject.Formulas" ) for key line1' – Mark Rogers Jun 05 '19 at 03:41
@MarkRogers does your `Formula` class implement (subclass) `Codable`? Also rmaddy is correct, you should be modifying the global. – jake Jun 05 '19 at 03:57
No, Formula does not have a subclass. I have another file AllFormulas class which then I use init() to declare each formulas values... Its in that class I am also declaring my arrays for lineOne1. Then in a AddViewController I select the formula I would like to append and view on my MainViewController in a tableView. – Mark Rogers Jun 05 '19 at 04:03
If you need to store an object in UserDefaults, I think conforming to `Codable` is best practice. See [this link](https://stackoverflow.com/questions/44876420/save-struct-to-userdefaults). Please note though you typically should use CoreData to store objects as opposed to UserDefaults, which is more often used for preferences. – jake Jun 05 '19 at 04:14
I did go the route of CoreData first but was having issues with formula I have showing in the tableview. I starting thinking UserDefaults might be an easier approach to the solution – Mark Rogers Jun 05 '19 at 04:18

UserDefaults array is coming back empty

1 Answers1