Kotlin extension functions - completion? I have watched a few tutorials on learning Kotlin, and I am confused as to the meaning of the word 'completion' as used in the quote below. The speaker is a developer at JetBrains, and this is taken from a transcript (not youtube subtitles): Here, we define an extension function to string called lastChar, and we can use it as a member function. It's visible in completion, so it can be easily discovered. It's like a regular utility function defined outside of the class. But on the other...

How to flatten list of list values in groupBy in Kotlin I have an object structure data class File( val travelBatch: List ) { data class TravelBatch( val currency: String, val transactions: List ) } I want to have a map of currency to transactions. The below code I tried gives Map

Android Kotlin RecyclerView in Fragment is not working I'm very new in Kotlin and Android programming. I tried to create a Fragment which populates a Recycler view, but somehow I get the following error: E/RecyclerView: No adapter attached; skipping layout I don't really understand why I get this, since I binded everything. If somebody can explain what I'm doing wrong I would really appreciate it. My code is the following: My class: data class Movie(val id:Int, val posterPath:String, val vote:Double, val language:String,val releaseDate:String,...

how to delete an item from a lazy column in jetpack compose I built a lazy column that gets it`s data from ViewModel and every time I add an item the lazy column recomposes and the new Item is being viewed in the lazy column, But when I added the functionality of deleting an Item the lazy column does not recompose and the removed item stays on the screen until a configuration change happens (Like rotating the screen). My question is how to make the lazy column know that the list has been updated after each Delete operation. here is the ViewModel:...

Check for a value in Kotlin immutable list I need to condense the following lines in kotlin to a more elegant way. I'm not able to figure out how to check the optional and the values at the same time. Basically I need to verify the list 'a' exists, has one or more items and that they are not 0. val a = Utils.getItems() // returns an Optional if(!a.orElse(ImmutableList.of()).size > 0) { val nonZero = a.get().filter { it.item != BigDecimal.ZERO } return nonZero.size > 0 }

Problem with RecyclerView in Globalscope.launch When I launch, I have this error android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. class FirstFragment : Fragment(){ private val TAG: String = "Information from app" lateinit var response:Response private lateinit var post :Reqres public lateinit var listus :List override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ):...

Soft Keyboard-like layout behavior I'm creating a messenger app and I want to add a button that opens a panel for selecting a sticker. Currently, the xml code consists of a RelativeLayout and a RecyclerView for displaying stickers. For hiding and showing, I just change the visibility of the container. Code in my chat fragment: if (/* need show */) stickerPanel.Visibility = View.VISIBLE if (/* need hide */) stickerPanel.Visibility = View.GONE But with this use, there are disadvantages. When the soft keyboard is...

How to insert Entities with One to Many relationship in Room database in Kotlin I am building a database using Room database in Android studio, And I cant figure out how to Insert the new Elements that have a relationship(one to Many in my case) into the database. and no one has ever talked about the insertion in this case (They only talk about getting the data from the database). Thanks in advance for any answers. Here is the Dao (Data Access Object): abstract class ShoppingListsDao { @Query("SELECT * FROM ShoppingList") @Transaction abstract fun...

Teamcity Kotlin Scripts rename IDs I have an auto generated Kotlin Script. steps { script { name = "Style check" id = "RUNNER_633" enabled = false scriptContent = """ #!/bin/bash make docker run="make ci lint" """.trimIndent() } script { name = "Build code" id = "RUNNER_662" scriptContent = """ #!/bin/bash make docker run="make ci" """.trimIndent() } stepsOrder =...

setBackgroundColor confusing black to white hey so I am programming and my app is supposed to have this imageView, and I should be able to change the color os that imageView by setbackgroundcolor, but the thing is, this function is confusing the colors scrollNumber.addOnValueChangedListener { if (color == "red") red = it if (color == "green") green = it if (color == "blue") blue = it image_input.setBackgroundColor(Color.rgb(red,green,blue)) Ok so I start with (255,0,0) witch means pure...

Why does my Word Unscrambler App keep on closing? I'm attending an Android programming class, and this weeks assignment is an Unscrambler app. I have the solution code (down below), but the app keeps on closing when I run it. Here's the code: GameFragment.kt import android.os.Bundle import android.util.Log import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import androidx.fragment.app.Fragment import androidx.fragment.app.viewModels import com.example.android.unscramble.R import...

How to create a list while iterating in Kotlin I am stuck with basic kotlin issue. I have a List which contains certain fields and I need to create a List while iterating over the 1st list and at the same time populating the data in the second. I am doing it using : List recordList = //getting the list from DB recordList.map {} I basically need kotlin version of this java code: recordList.stream() .map(m -> Males.builder() .id(m.getId()) .number(m.getLicenceNumber()) .build())...

mixing OOP and FP in one Kotlin project i am starting some Kotlin projects and i want to use both the OOP/FP strengths but i am hit with a real question. when? how? which feature i should use from each way? So far i decided to use OOP to create data and manage it and FP to control and use the data and create function with it but i don't exactly have a clear idea of all the features i will be needing in my project knowing that my project is to work with medical staff that will require a business side dealing with a lot of...

Why do I get an error in my instrumentation testing? Android kotlin So I have an app that has a home activity. In this home activity, there is a tab layout which has the title "Movies" and "TV Shows" and each tab has a fragment that contains a recyclerview listing movies and tv shows. I'm trying to do an instrumentation test. The case is first scrolling down through the RV in the movies tab and clicking at item 0 and checking all the views. Then I'm gonna proceed to move the tab to the TV shows tab and do the same. However, when I commanded to click on the...

ScrollView not scrolling when setting y value on views I'm fairly new to android development, and I've been banging my head against a wall on this issue for over two weeks now. I've started my android development with learning Kotlin. I have a ScrollView as part of an application layout, with a layout inside of the ScrollView. I programmatically position the TextSwitcher-based buttons laid out in the XML, mostly to size the buttons and move them off-screen. The buttons are meant to slide on-screen with a Spring animation. The issue is that...

Kotlin Multiplatform serve ktor as backend jvm module I'm working on my multiplatform project and added ktor based backend as part of it as i wanted to share my common code with this backend module i've added it to dependencies implementation(project(":shared")) But there seems to be an issue with sharing code for jvm target(which ktor backend is) I've found a workaround to have my project got this dependency resolved by marking this backend submodule as a multiplatform itself, but now as I build it and start to run I'm getting this error Error:...

How to go to new activity from fragment using navigation graph? (Kotlin) I've been using only fragment to fragment using navigation graph in my project. But I'm planning to add a button in one fragment and when i click the button it will bring me to new activity. I tried using normal intent and navigation controller to do that but both didn't help. The app will closed whenever i clicked the button. Does anyone know how to do it? I'm using kotlin. Thanks

How to disable to edit some part of text in EditText? When user open a dialog, an edittext appears with a text. How can I block the user to edit .db part. I want user to only change the test100Mb text. How can I do this ?

Kotlin library error NetworkOnMainThreadException I added a Kotlin library as a module to my project, the library get some data from Json file located in the same library in (assets folder), i want to call the Json file from a Url instead of the local file. so i managed to add the Url in the class class CoinProvider(private val context: Context, isTestnet: Boolean) { val result = URL("http://mylink.com/file.json").readText() val result1 = URL("http://mylink.com/file1.json").readText() private val filename: String = if...

How to avoid unnesary naming with Kotlin native serialization? Situation Say I have this JSON, which I get from some server: { "useless_info": "useless info", "data": { "useless_info2": "useless info 2", "children": [ { "kind": "Car", "data": { "id": 1, "transmission": "manual" } }, { "kind": "Boat", "data": { "id": 2, "isDocked": true } } ] } } This JSON is an example. It represent a much larger and complex one, but with...

Kotlin navigate with fragment name not id If I use something like this navController.navigate(R.id.action_nav_home_to_profileFragment) it does navigate me to destination fragment (from my main fragment) because it has action in mainFragment navigation file, but if I'm in other fragments it does not navigate because it doesn't have actions in those fragments. My question is: is that possible to navigate to my destination fragment from any fragment without using action id? instead using fragment name? PS: this button is placed in my...

Data interchange between two android apps in different device and different network? Is that possible two android apps communicate and data interchange through Internet without need any other server. Like : One android app called "App A" and other app called "App B" "App A" and "App B" are in different devices and under different networks. I want "App A" send a message to "App B" , and "App B" respond to that.I don't need any third party servers between the apps, just through internet and using ip address. I tried using Ktor framework. But it's only works under same network....

Failed to load resource: the server responded with a status of 404 () . Swagger Configuration not working Swagger Configuration not working I use swagger with springboot , i am getting error404 when i hit this url http://localhost:8080/swagger-ui.html. I am new to swagger I have no idea how to solve it. I create separate configuration file Failed to load resource: the server responded with a status of 404 () Here all the documentation details UserCongig.kt package com.main.swaggerdemo.config import org.springframework.context.annotation.Bean import...

Android Unit Testing method that contains Composite Disposable I am new to Unit Testing for Android and I tried to create the unit test for the function, it works but the lines inside subscribe() are not covered, I wanted to know how can I write the test to cover the lines which are inside the subscribe() private void loadPictureOfTheDay(Context context, RemoteViews views, AppWidgetManager appWidgetManager, int appWidgetId) {...

Why it's unresolved reference error for calling setBackgroundResource() on an ' id ' in Mainactivity.kt? package com.example.colormyviews import android.graphics.Color import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.view.View import android.widget.Button import android.widget.TextView class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) setListeners() } private fun setListeners(){ val...

How to combine polymorphic and transforming serializers for nested JSON, using Kotlin serialization? This is a simplified example of the JSON I want to work with: { "useless_info": "useless info", "data": { "useless_info2": "useless info 2", "children": [ { "kind": "Car", "data": { "id": 1, "transmission": "manual" } }, { "kind": "Boat", "data": { "id": 2, "isDocked": true } } ] } } children is an array of vehicle objects. vehicle can be boat or car. My Problem...

When using coroutine channels, how do I activate the -> operator? In this example, https://kotlinlang.org/docs/channels.html#prime-numbers-with-pipeline We are given two functions: fun CoroutineScope.numbersFrom(start: Int) = produce { var x = start while (true) send(x++) // infinite stream of integers from start } fun CoroutineScope.filter(numbers: ReceiveChannel, prime: Int) = produce { for (x in numbers) if (x % prime != 0) send(x)...

How to apply Indent to array json in java we are reading the file changing the content and writing back to the same location how to apply Indent to json array in java/only specific properties source code import com.google.gson.JsonElement; import com.google.gson.internal.Streams; import com.google.gson.stream.JsonReader; import com.google.gson.stream.JsonWriter; String file="D:\\Documents\\read.json"; JsonElement root = Streams.parse(new JsonReader(new FileReader(file))); // changing the json values here...

Direct App Deep Link not working evethough all configs are correct in Android I am trying App Linking from URL in Android , that is opening app directly when clicking a respective link without showing suggestions from intent chooser (app not yet live in play store ) Eventhough all of my configs are correct ... Direct app Link is not working , only I am getting app name in the suggestions I also tried with app link verifier from google . It having an weird issue In the initial attempts , its...

UI Testing with Hilt I am trying to mock a view model in my UI Tests. It seems like I don't have it set up correctly, because the VM in the test activity is "not initialized". This is what I got: Hilt Module that provides my VM: @Module @InstallIn(SingletonComponent::class) object ApplicationModule { @Provides fun provideMainViewModel(sharedPreferences: SharedPreferences): MainViewModel = MainViewModel(sharedPreferences) } Test Module to provide mocks: @Module @TestInstallIn( components =...