CODEWITHSUNDEEP
kotlin
weera
weera

Reputation: 942

Define setter for Maps in Kotlin

Assume I have this property in a class:

private var dates: Map<String, Long?> = mapOf(
    "creation" to System.currentTimeMillis(),
    "lastUpdate" to System.currentTimeMillis()
)

Now, I need to update "lastUpdate" timestamp using function below:

fun start(): Boolean {
    this.dates["lastUpdate"] = System.currentTimeMillis()
    return true
}

I get this Error:

"No set method providing array access"

How should I define setter and getter methods for maps?

Upvotes: 0

Views: 513

Answers (1)

Animesh Sahu
Animesh Sahu

Reputation: 8096

Kotlin's Map is immutable, i.e. you neither can edit any values in it nor you can add any new values.

In Kotlin there is seperate interface that does give you operator fun get() and operator fun set() in it, it is actually a MutableMap, an extension to the Map.

You can create MutableMap using the mutableMapOf function in the standard library.

private var dates: MutableMap<String, Long?> = mutableMapOf(
    "creation" to System.currentTimeMillis(),
    "lastUpdate" to System.currentTimeMillis()
)

// Then change whatever you want to
dates["lastUpdate"] = System.currentTimeMillis()

Upvotes: 5

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