How can I pass data from a Playground Page to another Playground Page in Swift Playgrounds?

Question

Created Apr ’21

Replies 2

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I am making an PlaygroundBook for Swift Playgrounds [Not Xcode Playgrounds]. I want pass data between playground pages.

Example, I have an public variable in UserModule and its value is 0. In first page, user change this variable to 1. When user go to second page, variable's value is 0. But I want its value is user's value (1). How can I do that?

I'm using SwiftUI. I tried to use UserDefaults but UserDefaults won't work truly in Swift Playgrounds. And also try to save datas to a JSON file but Playground won't write files (only read). I also tried this but it isn't work too.

Answered by alpereno in 671175022

Answered on another forum.

You'll want to use PlaygroundKeyValueStore. This works similar to UserDefaults, but on playgrounds. Keep in mind that it only deals with PlaygroundValues, so you'll have to wrap your value.
You can do something like:

Code Block public var myVariable = 0 {
    didSet {
        PlaygroundKeyValueStore.current.keyValueStore["myKey"] = .integer(myVariable)
    }
}

Then, on the other page, you can retrieve the value with:

Code Block guard let keyValue = PlaygroundKeyValueStore.current.keyValueStore["myKey"],
    case .integer(let storedValue) = keyValue else {
    // Deal with absence of value
}
// Use retrieved value

You should probably also store you keys on an enum, for example, to avoid mistyping.

Code Block enum StoredVariableKeys: String {
    case myVariable1
    /* ... */
}

And use this value for your key, like

Code Block let myKey = StoredVariableKeys.myVariable1.rawValue;

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Answer 1

alpereno OP

Apr ’21

Accepted Answer

Answered on another forum.

You'll want to use PlaygroundKeyValueStore. This works similar to UserDefaults, but on playgrounds. Keep in mind that it only deals with PlaygroundValues, so you'll have to wrap your value.
You can do something like:

Code Block public var myVariable = 0 {
    didSet {
        PlaygroundKeyValueStore.current.keyValueStore["myKey"] = .integer(myVariable)
    }
}

Then, on the other page, you can retrieve the value with:

Code Block guard let keyValue = PlaygroundKeyValueStore.current.keyValueStore["myKey"],
    case .integer(let storedValue) = keyValue else {
    // Deal with absence of value
}
// Use retrieved value

You should probably also store you keys on an enum, for example, to avoid mistyping.

Code Block enum StoredVariableKeys: String {
    case myVariable1
    /* ... */
}

And use this value for your key, like

Code Block let myKey = StoredVariableKeys.myVariable1.rawValue;

0

Answer 2

aheze OP

Apr ’21

Btw, PlaygroundKeyValueStore.current.keyValueStore["myKey"] didn't work for me. Instead, try

Code Block PlaygroundKeyValueStore.current["myKey"]

0