How do I use getters and setters for a variable of type array to access items of the array by index instead of the entire array itself

Question

Created Jul ’18

Replies 3

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class SomeClass {
     var dates: [Date] {
          get {
               return ckRecord.object(forKey: "dates") as! [Date]
          }
          set(newDates) {
               ckRecord.setObject(newDates as! CKRecordValue, "dates")
          }
     }
}

In the previous code, how do I write code in the get and set closures to save to CloudKit and retrieve the data from CloudKit everytime I get one of the values from the array or set one of the values in the array, which means I don't retrieve the whole array or set the whole array, only one of the values at a given index as in the following code:

var obj = SomeClass()
obj.dates[0] = Date()

I don't have a problem using CloudKit. I have a problem figuring out how to arrange the code for the get and set closures so that I properly access the array from the CloudKit record by index. I am attempting to wrap the CloudKit record in class SomeClass.

Any help will be appreciated.

Answered by DTS Engineer in 322157022

Could you give me some references or key words to search for in documentation?

I don’t think there’s any documentation that explicitly covers these approaches. Rather, you have to build the approach by combining ideas that you’re probably already familiar with, namely structs, classes, and subscripts.

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Apple Developer Relations, Developer Technical Support, Core OS/Hardware

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Answer 1

DTS Engineer OP

Apple

Jul ’18

There’s a couple of ways you could approach this:

Create your own type, call it
```
DateArray
```
, that supports subscripts, and use that for you
```
dates
```
property (A).
Change your approach so that you convert your
```
CKRecord
```
to a standard Swift model object on input and then convert it back when you go to save (B).

Which is best really depends on what sort of flexibility you want in the clients of this class. If those clients only do a limited set of operations on

dates

, option A might be reasonable. However, if you want the clients to be able to use

dates

exactly like a real Swift array, it’s likely that option A will be hard and a switch to option B would be in order.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

0

Answer 2

ShinehahGnolaum OP

Jul ’18

How would I do either of those. Could you give me some references or key words to search for in documentation?

0

Answer 3

DTS Engineer OP

Apple

Jul ’18

Accepted Answer

Could you give me some references or key words to search for in documentation?

I don’t think there’s any documentation that explicitly covers these approaches. Rather, you have to build the approach by combining ideas that you’re probably already familiar with, namely structs, classes, and subscripts.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

0