ArrayMap does not support square bracket assignment

[limbusdev]

Hi,
great extension to libGDX :) thank you for that.

My question: how can square brackets be used with libKTX ArrayMaps?

what I wanted to to:

val myMap : ArrayMap<String, Label>
myMap = ArrayMap()
myMap["one"] = new Label(...)

But there is no Set operator defined. Am I doing something wrong, or isn't it just implemented yet?

Cheers

[jcornaz]

You have to create an extension function for it:

operator fun <K, V> ArrayMap<K, V>.set(key: K, value: V) {
  put(key, value)
}

Eventually it could be added to ktx...

[limbusdev]

yeah, hoped it's already been there - thank you :)

[czyzby]

LibGDX introduced a lot of custom collections without a common interface, which makes adding such extensions very redundant. We focused on the most common collections. As of writing this, ktx-collections adds utility methods for ObjectMap and IdentityMap, but I believe ArrayMap was omitted.

[limbusdev]

Yeah, but it had been said, that the libgdx implementations are more efficient and use less storage. Nevermind, I did what jcornaz explained and extended it myself. Thank you.

[czyzby]

@limbusdev FYI, from the documentation:

An ordered or unordered map of objects. This implementation uses arrays to store the keys and values, which means #getKey(Object, boolean) do a comparison for each key in the map. This is slower than a typical hash map implementation, but may be acceptable for small maps and has the benefits that keys and values can be accessed by index, which makes iteration fast.

ArrayMap is rarely a good choice, since it loses the main advantage of a hash map. If garbage collection is an issue and you want to rely on LibGDX collections, you should use ObjectMap instead.

I still think we could add some basic utility methods for ArrayMap, but it's a rather niche collection.

[czyzby]

Removed some spam.