Kotlin provides the ability to extend a class with new functionality without having to inherit from the class or use any type of design pattern such as Decorator. This is done via special declarations called extensions.
Questions tagged [kotlin-extension]
333 questions
0
votes
1 answer
Add new custom properties to retrofit2.Response
In my android app:
Here my interface method:
import retrofit2.Response
import retrofit2.http.GET
import retrofit2.http.Path
import retrofit2.http.Query
@GET("traders/json")
suspend fun getTraidersList(): Response>
Nice.
but I need to…
Alexei
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1 answer
How to write extension function with nested generics?
I have extension function on Single class:
fun > Single.checkResponse(): Single {
return this.map { some code }
}
And trying to use it like:
fun sign(body: Map): Single {
…
Alexey Lariushkin
- 13
- 3
0
votes
1 answer
Kotlin how to combine different receivers via with clause without repeating it
I have Parent-Search-Child system as below:
class Room
class Building {
fun find(by: By) = Room()
}
sealed class By {
abstract fun search(): Room
class ById(id: String) : By() {
override fun search(): Room = Room() // epic…
xinaiz
- 7,744
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0
votes
1 answer
Data from firebase realtime wont display on my recyclerView
I need to display data from firebase database using a recyclerView. everything works fine, I can see the cards and all but there wont be and data on the card.
here is my adapter class:
class MyAdapter(c: Context, t: ArrayList) :…
shohoud n
- 3
- 2
0
votes
2 answers
How to access a view inside of another class using Kotlins view binding
I am currently following a Tutorial about RecyclerView, which is "written" in java.
Now I am trying to basically take the tutorial and code it in Kotlin.
I now want to access Views from the layout_listitem.xml (which basically just describes the…
Matthias Hofmarcher
- 384
- 1
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- 11
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votes
1 answer
How can I add some generated code in existing method
Synthetic adds clearFindViewCache() in Activity.onDestroy() and Fragment.onDestroyView() methods. How can I add extra code to existing method with my own annotation processor?
If we look to the synthetic's implementation we can see usage of classes…
Vlad Kudoyar
- 371
- 3
- 8
0
votes
2 answers
Kotlin pass function as a parameter vs lambda implementation
I'm using the io.reactivex.rxkotlin extension function:
fun Observable.subscribeBy(
onError: (Throwable) -> Unit = onErrorStub,
onComplete: () -> Unit = onCompleteStub,
onNext: (T) -> Unit = onNextStub
…
CookieMonster
- 1,723
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- 15
0
votes
2 answers
Possible to Kotlin extend/override Double.toString to produce less decimal places?
I already have a hack:
/** Shorter round for the logs */
val Double.str: String
get() = "%.3f".format(this)
But that has to be manually inserted into all of my LOG.info { "It went ${distance.str}" } statements. I'd prefer to be able to set the…
Benjamin H
- 5,164
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1 answer
how to get the coefficients out of the polynomal expression?
At the input I get a polynomial as a string,
I want to get its coefficients in variables, but i have no idea gow do this.
example:7x^4+3x^3-6x^2+x-8.Maximum degree is not known, coefficients are integers.
I will be very grateful for any help.
Marlock
- 275
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0
votes
0 answers
Cannot choose among the following candidates without completing type inference
I have these three helper extensions:
fun BaseQuickAdapter.onItemClick(
onItemClick: (adapter: BaseQuickAdapter<*, *>, position: Int, item: T) -> Unit
): BaseQuickAdapter {
setOnItemClickListener {…
humazed
- 74,687
- 32
- 99
- 138
0
votes
1 answer
How to unit test an kotlin extenion function that has a generic type
kotlin 1.2.51
I have the following shared preferences that uses a generic extension function.
class SharedUserPreferencesImp(private val context: Context,
private val sharedPreferenceName: String):…
ant2009
- 27,094
- 154
- 411
- 609
0
votes
2 answers
Kotlin Class Extension
I'm just learning Kotlin as a fun side-project for Project Euler. I just started literally 5 minutes ago, in IntelliJ IDEA.
I have this code:
fun Number.isMultipleOf(n: Number): Boolean {
return this % n == 0
}
fun main(args: Array){
…
mackycheese21
- 884
- 1
- 9
- 24
0
votes
2 answers
Extension function on a generic type
I am new in Kotlin and I am trying to understand type alias and functions.
I have the following example:
interface EmptyInterface
typealias GenericCase = T.(EmptyInterface) -> T
val myFunctionVariable: GenericCase = {
_ -> "Hello…
Jim
- 3,845
- 3
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- 47
0
votes
1 answer
Kotlin Extensions - Synthetic imports show compilation error in child class
I have a class A where my view fragment_my_quests is defined. Synthetic imports works fine in class A.
Now I extend B with A and try to use Synthetic import and id's inside my child class B.
It shows red (compilation error). But when I run the app,…
Harsh
- 599
- 3
- 20
0
votes
1 answer
How can I test/access companion object extension functions in Kotlin?
I have an Base64Util class with amongst others an extension function decodeBase64ToByteArray :
class Base64Util {
companion object {
fun String.decodeBase64ToByteArray(): ByteArray {
return Base64.getUrlDecoder().decode(this)
}
…
Tranquillo
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