Best practice to update LiveData from RecyclerView I am doing an app with Android Architecture Components. One particular screen is populated with dynamic elements(views). Those dynamic elements are displayed inside a RecyclerView with a custom RecyclerView.Adapter Some of the elements that might appear are some control elements like selectors for date/time, location... etc. Depending of this selection, the values of the other views should change (read-only views). The holding Fragment has (Android)ViewModel with LiveData that emits the...

How do I assign byte in kotlin? I am trying to assign byes in a ByteArray in Kotlin, I just don't know the syntax of assigning a byte. for example in c if I want to assign a char I would do: char c = 'a'; But what is the syntax for assigning a byte in a byte type variable in Kotlin language ? I just can't find an example, let's say I want to assign the byte E0 in array[i], how do I do it ?? Thank you very much

How to signal an Observable to produce more data Is there any way to signal an Observable to produce more data? I have a buffered Observable that produces 10 items and i want it to continue producing more items only when i want to. To be more specific, i have an infinite scrolling Recycler View, i want to produce more items only when i continue scrolling to the end.

Make a short if statement In my code I have this if statement: if (categoryName == "SomeName1" || categoryName == "SomeName2" || categoryName == "SomeName3" || categoryName == "SomeName4" || categoryName == "SomeName5" || categoryName == "SomeName6") { // Do something } I was wondering if I could shorten this if. Something like: if (categoryName == "SomeName1" and "SomeName2" and "SomeName3" ...) { // Do something } Is there any aproach to do something like this in Kotlin?

Long vs String when querying by date and sorting by time with Android Room? According to best practices, one should convert Date to Long for sqlite : @TypeConverter fun dateToTimestamp(date: Date?): Long? { return date?.time } Concretely, I need to query and order records by date. This works : @Query("SELECT * FROM t WHERE date(d / 1000, 'unixepoch', 'localtime') = date(:date / 1000, 'unixepoch', 'localtime') ORDER BY d") The result I'm looking for : @Query("SELECT * FROM t WHERE date(d) = date(:date) ORDER BY d") I know I can get easily get rid of the...

How can I make an icon that counts comments I am trying to set an icon that counts the number of comments on a post like this How can I code this

kotlin class nto found I have created an Android studio 3.0.1 project using kotlin. Everything is working fine. I can run the project it works, I can run unit test for classes too. But When i try to run a single Kotlin project it gives following error, Exception in thread "main" java.lang.ClassNotFoundException: classes_properties.MainExampleKt at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at...

Kotlin Application with Gradle application plugin I am trying to create a simple HelloWorld application using kotlin, gradle, and the gradle application plugin. When I run it with the below setup I get the following error: Error: Main method is not static in class com.petarkolaric.helloworld.Main, please define the main method as: public static void main(String[] args) My build.gradle: group 'helloworld' version '1.0-SNAPSHOT' buildscript { ext.kotlin_version = '1.2.0' repositories { mavenCentral() }...

How to get "key" many unknown child in Firebase? I have FireBase there are a lot of "devices" names and place where they situated. But I don't know how to get all information if I have four "services" and 100 device in each. This code get all info what I need , but I wrote the name of "device" and name of "service", but how to get info from all "services" and "devices" inside them? [onDataChange inside onDataChange ??] fun allTabLikesAndDislike(tabLikeNumber:...

Moshi: Expected a Class, ParameterizedType, or GenericArrayType, but <null> is of type null I have this model: class Model1 { var attributes: Map? = null } I expect a list of these models. Sample JSON: [ { "attributes": { "title": "New Year's Day", "country": "SG" } }, { "attributes": { "staff_id": 320011, "title": "Labor day", "date_joined": "2017-01-10 000000", "years": 1 } } ] Then I get this error during deserialization: Caused by:...

Incorrect behavior of Maybe<List<T>> in Room? I have the following query method definition: @Query("SELECT * FROM box_jobs") fun getAll(): Maybe I want to return the result of this query if it's not empty or the result of the REST API call otherwise. This is my code for this logic: override fun loadTasks(): Maybe { Log.d(TAG, "Searching tasks in database") return boxJobDao.getAll() .map { boxJobs -> boxJobMapper.entityListToTaskList(boxJobs) } .switchIfEmpty(syncTasks()) } private fun syncTasks():...

Android application on Gradle: Unable to merge dex I have an error with my app in Android studio: Execution failed for task 'apptransformDexArchiveWithExternalLibsDexMergerForDebug'.

com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex

I use Gradle and Kotlin. Android Studio 3.0.1. Windows 10 Pro 64. I have research this theme on SO and I have tried some solution from here, like that: Clean and rebuild project. No changes....

Kotlin Activity memory leak I just write a Activity use Kotlin,it's very sample,The code below: package com.chiquedoll.chiquedoll.view.activity import android.os.Bundle import com.chiquedoll.chiquedoll.R import kotlinx.android.synthetic.main.view_normal_toolbar.* /** * Created by super-zuo on 17-12-12. * Description: */ class TestActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_edit_profile)...

how to implment Switch using Data binding in android this is my xml : this is my View Model class NotificationViewModel(val context: Context, val bus: Bus, val manager: CNotificationManager) : BaseObservable() { private var checked: Boolean = false fun getToolbarTitle(): String? { return manager.getToolbarTitle() } fun setToolbarTextColor(): Int { return ContextCompat.getColor(context, R.color.colorDusk) } fun isChecked():...

Determine whether an instance is an instance of a data class Given the following classes abstract class SomeAbstractClass data class DataClass() : SomeAbstractClass() class NoDataClass() : SomeAbstractClass() For any instance of SomeAbstractClass, can I determine whether it is a data class without relying on type checking? Some background: this seemed the best way of combining inheritance and data classes to me, <a...

Java Math like classes in Kotlin How we can create Java Math like Util classes in Kotlin. So that I can call something like Math.add() . I try to do using companion object. Let me know if there is other way to do it.

DSL-like OnClick-listener for a custom view using kotlin in Android I'm trying to create an DSL-like OnClick-listener (in kotlin) for a custom view that I'm using several places in the Android project I'm currently working on. The view has an ImageView, a primary textview and a secondary textview. I'm trying to create a listener-helper that allows you to only override specific methods of an interface instead of all of them (inspired by <a...

Why texts are not changing in activity? By studying databinding, I created a simple activity to start exercising. And have the following codes: MainActivity: class MainActivity : AppCompatActivity() { val users = UserProfile("First Name","Last Name","Off",false) val handlerbtn = HandlerButtonClick() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val binding: ActivityMainBinding = DataBindingUtil.setContentView(this,R.layout.activity_main) binding.user =...

How can I do standard library's dead code elimination for Kotlin JVM? I know in Kotlin js mode, if we consider the standard library too large, we can use kotlin-dce-js gradle plugin. But I'm developing Kotlin JVM. So is there a similar plugin that does the same job for kotlin jvm as kotlin-dce-js does for kotlin js? Or, how can I use Kotlin without the standard library? (without the standard library, I can't even use Int/Doubles. But I don't want to use the Collection APIs, or some other extensions in the standard library) Or, is there s smaller Kotlin...

run android studio 2.3.3 kotlin project in android studio 3.0.1 after update i have updated AS 2.3.3 to 3.0.1 using a patch .jar the update was successful however android studio keeps reminding me that i need to update Kotlin plugin. This Kotlin plugin was installed in the 2.3.3 version but think that android studio 3.0.1 doesn't require a Kotlin plugin. So my question is what should i do in the old project so that it works fine in AS 3.0.1

Using Kotlin reflect prints &amp;quot;Bad class file signature&amp;quot; in terminal I am currently trying to use kotlin-reflect-1.2 + kotlin-stdlib-jdk8 and I am getting these errors on command line: [See bug 406167] Bad class file signature encountered, nested types appear package qualified, ignoring those incorrect pieces. Signature: ()Lkotlin/reflect/jvm/internal/ReflectProperties$LazyVal.kotlin/reflect/jvm/internal/KClassImpl$Data;>; [See bug 406167] Bad class file signature encountered, nested types appear package qualified, ignoring those incorrect pieces....

Ignore return value from function [duplicate] This question already has an answer here: How to convert function output to Unit with Kotlin 2 answers Is there any way in Kotlin to ignore the return value of some function? Example fun checkSomething(number: Int) : Unit = when(number) { 1 -> intFunction() //...

Android (Kotlin): Overwrite name for call log entry I'm currently trying to build an app, which can initiate a call from a list of contacts pulled from a rest API, using: val callIntent = Intent(Intent.ACTION_CALL) callIntent.data = Uri.parse("tel:${entry.phoneNumber}") startActivity(callIntent) Since, to my knowledge, it isn't possible to pass along any info to be used for the resulting call log (The 'call history' in the dedicated 'Phone' app). I going to update the call log myself. Currently i fetch the call log via: //Specifiy...

Changing kotlin extension function receiver JVM name This is a general question. Let's say I have an extension function written in kotlin which converts DP to PX and return a NonNull Int fun Int.toPx() { /** implementation */ } The function in java will look something like this public int toPx(int $receiver) { /** implementation */ } In my opinion the $receiver makes the Java-interop feels generated and uninviting. I know that you can use the @JvmName annotation with some combinations like @file:JvmName to change the name in java....

Unexpected behaviour with AWS Lambda What I've done I've created a project using Serverless cli, from aws-kotlin-jvm-maven template. After that I've edited my serverless.yml template this way: service: test provider: name: aws runtime: java8 region: eu-west-1 package: artifact: target/test-1.0.0.jar functions: hello: handler: com.example.Handler events: - schedule: rate(2 minutes) And I've edited my Handler this way: class Handler:RequestHandler { override fun handleRequest(input:Map,...

Single time events in MVI architecture Trying new architecture paradigm where presenter creates immutable state(model) stream and view just renders it. Can't understand how to handle situations where we need to make some event for the one time only. There are couple examples. 1) Notes app. We have editText and saveButton. User clicks saveButton, some processing happens and editText should be cleared. Could you guys please describe what will be in our ViewState here and approximate logic flow? Questions and pitfalls I see now:...

streaming ve non streaming services service kgrpcServer{ rpc addE1(E) returns(newId){} rpc addE2(stream E) returns(newId){} } When I try to perform bulk operations through grpc (meaning 5000 inserts of E), I discovered that althoug in principle using the stream version should be sensible faster than the non streamed (as there is no acknowledgment from the server side to the client), in fact the non streamed version is consistently faster than the streamed one. Does it make any sense? In both cases I use a non blocking...

java.lang.RuntimeException: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex My project is in Kotlin on Android Studio 3.0.1 this is my design gradle buildscript { ext.kotlin_version = '1.2.0' ext.anko_version='0.10.3' repositories { jcenter() mavenCentral() google() } dependencies { classpath 'com.android.tools.buildG3.0.1' classpath 'com.google.gmsgoogle services3.1.1' classpath "org.jetbrains.kotlinkotlin gradle plugin$kotlin_version" // NOTE: Do not place your application...

Unable to resolve host pokeAPI I want to get datas from pokeAPI for my android API. I have followed the instructions into this page https://github.com/PokeAPI/pokekotlin. I have add in bluid.gradle(module:app) dependencies : compile 'me.sargunvohra.libpokekotlin2.3.0' In build.gradle(Project): allprojects { repositories { google() jcenter() maven { url 'http://jcenter.bintray.com' } } } I have add this permission in...

Equivalent of Iterator.Remove in Kotlin HashMap? Sorry if this is a dumb question-- but in java I am used to doing something like the following: Iterator whatever = entrySet.iterator() while (whatever.hasNext()) { for (int i = 0; i < 4; i++) { if (i == 3) { whatever.remove(whatever.next().key) } } } (Pseudocode and the logic makes no sense) However, the "remove" function doesn't exist for a hashmap in Kotlin. I understand you can use removeIf for a single condition, but I want to loop through a bunch...