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Ludiras
Asked: 2020-05-09 05:33:47 +0800 CST 2020-05-09 05:33:47 +0800 CST

Scoping functions in Kotlin

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I am looking at the scope functions in Kotlin (let, run, with, apply, also) and I have a doubt between apply and with. I've read that apply is used when the value needs to return itself, but what does this mean? Since seeing the codes is almost the same:

val mediaItem = MediaItem("Title 14", "", MediaItem.Type.PHOTO).apply {
    title = "Title 15"
    imageUrl = ""
    typeElement = MediaItem.Type.VIDEO
}

with(mediaItem) {
    title = "Title 16"
    imageUrl = ""
    typeElement = MediaItem.Type.VIDEO
}

The only thing I see is that with needs the object to be used and with apply we use it from this object, but it is not very clear to me, let's see if any of you can explain it to me.

kotlin

1 Answers

  1. Best Answer

    Indeed they are very similar, the main differences are:

    • withdoesn't need an object to be called on, whereas it applydoes.
    • applyis executed on the object reference, while withpassing it as an argument.
    • The last expression withreturns a result.
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