How can max() sometimes be a lot faster on a sequence of the same length? I'm asking this question solely to better understand how kotlin sequences work. I thought I had a solid grasp, but I cannot explain what I observed in a short test by what I know, so obviously I have a misconception somewhere. My goal was to do a quick benchmark to compare the performance of lists vs. sequences when filtering for a criteria and then taking the maximum value of the result. This is an operation that occurs fairly often in some code I have, and I'm trying to decide whether or...

How to send data from fragment to Activity in Android In my application i want use Fragment and Activity and i want startActivity from this fragment and i should send data with startActivity I write below codes, but when running application show null in activity! Fragment codes : homeDashboard_giftInfoLayout.setOnClickListener { val intent = Intent(requireContext(), DashboardChargeWalletActivity::class.java) intent.putExtra(USER_WALLET_PRICE, response.user.wallet.credit) intent.putExtra(USER_CHARGED_VALUE, 0)...

Parse XML Array with SimpleXmlConverterFactory / Kotlin How can I parse an Array of XML Elements "echeance" form this XML format: 353 Ville 45 45 45 I want this data to be parsed in a Data object containing an array of "Echeance" objects, using SimpleXmlConverterFactory For now, i have this kotlin code : data class Data(val ville :String, val code :Int) { @get:Element(name="city") lateinit var city :String @get:Element(name="code") var remoteCode :Int = -1...

Is it safe to store data in a kotlin object? I have a question regarding objects in kotlin, to which i couldn't find a satisfying answer so far. It's basicly the following scenario: I've got some user data, that i want to make available through the entire app, without having to pass it through activities. To achieve this, i created an object with two properties that are instantiated with the users data in the startup activity. Is this a safe way to store and make the user's data available for all activities or will it get lost on the...

How to dynamically update textview inside recycler view with handler thread I'm trying to update my TextView with Handler thread from RecyclerView here the thread is getting executed successfully but my TextView is not getting updated every second. Here's my code: val timerHandler = Handler() var sec:Int=0 var min:Int=0 var hour:Int=0 updater = Runnable { sec.inc() if (sec>60){ sec = 0 min.inc() } if (min>60)...

Unable to call kotlin fragment from java class I have created new dialog fragment in kotlin but my project was in java. I have tried display dialog from another java fragment. I called from java like below new AlertFragment().show(getChildFragmentManager(),"AlertFragment"); It's shows build error with message error: cannot find symbol class AlertFragment what's would be issue and how do I resolve it? Thanks in advance

Private constants in Koltin? Currently I read a lot within classes. class Car : Driveable { private companion object { private const val AMOUNT_WHEELS = "4" } //.. use AMOUNT_WHEELS in this class somehwere } Please ignore that I store 4 as String here. Why companion? What would you use and why?

Kotlin load a new facebook page in app to webview after facebook login I want to load a new page to a webview in my kotlin app after user login to facebook. My login to facebook works fine but my problem now is that my webview loads my url in a new window and not in my webview and user need to login again. I need to use http and https with usesCleartextTraffic to true in AndroidManifest to load http. How to fix so that user can open a new url to webview after successfully log in to Facebook? My kotlin app works with Facebook log in and I have tried to load...

Should variable in coroutine body be synchronized with AtomicReference or Channel if only one inner coroutine changes it? Having simple variable in coroutine block and only one producer coroutine changes the state of the variable and another coroutine consumes it, should this variable be synchronized somehow with AtomicReference or Channel to be visible in reader coroutine or reader coroutine automatically fetches new data from the memory? fun main() = runBlocking(Dispatchers.Default) { var state: State? = null launch { data0Flow.collect { newState -> state = newState }...

Coroutines: Is there a way to block multiple executions and notify them all? I've been trying to implement a wait & notifyAll system like I used to do in Java. Main idea is to make multiple functions call to wait for a signal and continue their execution. The following test case wraps the intended implementation: @Test fun blocking_multiple_shouldReturnOne() { var valueOne : Int? = null var valueTwo : Int? = null var valueThree : Int? = null var valueFour : Int? = null val threadManager = ThreadManager() threadManager.startBlocking {...

Lollipin - layout customization I need to customize the layout for a pin code. Here is my layout for customization PinActivity But, I am getting this error: Caused by: android.view.InflateException: Binary XML file line #36: Error inflating class com.github.orangegangsters.lollipin.lib.views.KeyboardView Caused by: java.lang.ClassNotFoundException: Didn't find class "com.github.orangegangsters.lollipin.lib.views.KeyboardView" on path: I could not find a full guideline for customization.

How to figure out if some Kotlin standard library type is Serializable? In the following code, the linkedSet variable is of type LinkedHashSet: val linkedSet = linkedSetOf(linkedSetOf(1, 2, 3), 2) The first element of the resulting set is LinkedHashSet. Going up the hierarchy of LinkedHashSet I didn't find the Serializable. Same thing for Int. Why does inheriting the Serializable isn't explicit? And how can I figure out that some type is Serializable?

Vaadin 8 + Spring Boot -- restrict access to view Been playing around with Spring Security and Vaadin for a bit and I cannot seem to figure out how to attach role-checks to vaadin views. Example: ArticlesUI has two views: ArticlesView -- a simple display should be accessible to all authenticated users ArticlesEditView -- a display that also allows editing the collection should only be accessible to authenticated users that have ROLE_ADMIN authority Any way to use a WebSecurityConfigurerAdapter to restrict access to certain...

Passing Data to Intent / BroadcastReceiver I am calling an intent and the package is another app that I do not have control of. I have set up a BroadcastReceiver to listen and get a piece of data from the intent. This is working perfectly in the code I have attached. My issue is I now need to do different actions based on data I would like to pass in from the activity calling the intent. Is there a way to pass the data from my activity to the BroadcastReceiver that I can use? Any and all help is appreciated. I have tried to use a...

Using implicit variable in function literal I started reading Kotlin course book. I stopped on function literals. Here I have a code: val printMessage = { message: String -> println(message) } printMessage("hello") printMessage("world") Then I have an information that I can omit parameter type: { message -> println(message) } And now I have next step: "In fact, Kotlin has a neater trick. If there is only a single parameter and the type can beinferred, then the compiler will allow us to omit the parameter completely. In this...

parsing solr response with nested list of values I am trying to parse the 'column' and 'restricted' names(the column and restricted lists will only ever contain 1 element) from a response from Solr that looks like this: val objectString = """{ "responseHeader":{ "status":0, "QTime":5, "params":{ "q":"column:card_num,first_name,last_name"}}, "response":{"numFound":2,"start":0,"docs":[ { "column":["card_num"], "restricted":["y"],...

how can i change default speed of viewpager auto sliding in kotlin? I use below code to change default speed of sliding in viewpager. I try java code, This Stackoverflow question's Help I use below kotlin code to set limit of animation of auto swipe of view pager val mScroller = ViewPager::class.java.getDeclaredField("mScroller"); mScroller.setAccessible(true); val scroller = Scroller(requireContext(), DecelerateInterpolator());...

How to replace Koin service injection in a Ktor route test by a mocked service I want to make a test for a Ktor route that uses Koin to inject a service. I am struggling to mock the service used by the Ktor route in my test. Here is the Ktor Application.kt file @kotlin.jvm.JvmOverloads fun Application.module(testing: Boolean = false) { install(Locations) { } // Suppressed code installKoin(listOf(dependencyInjectionModule)) routing { val eventService by inject() get("/issues/{issueNumber}/events") { val issue =...

How to use fx:id for tab content in kotlin/tornadofx? Using the following code always ends with: Caused by: kotlin.UninitializedPropertyAccessException: lateinit property textArea has not been initialized at kam.applogviewer.main.LogTab.setContent(LogTab.kt:20) It happens when I call LogTab::setContent(lines). Maybe this isn't the right way to use FXML with a tab in tornadofx? MainView.kt (snippet): class MainView : View("Example") { ... fun showFileContent(fileName: String, lines: List) { val logTab =...

Firebase Kotlin Reference more than one child I'm using Firebase Realtime Database for my Android application using Kotlin. I have my JSON in the below format. { "main1": { "branch1": [ { "a": "Test1", "b": "Test2" }, { "a": "Test3", "b": "Test4" } ], "branch2": [ { "a": "Test5", "b": "Test6" }, { "a": "Test7", "b": "Test8" } ] } } I want to get results for more than one child and get them displayed...

Initialize Bitmap array in Kotlin I'm new in kotlin and I'm tryng to understand how can I initialize this array in the correct way. My java code: private Bitmap[] leftToRights; private Bitmap[] rightToLefts; private Bitmap[] topToBottoms; private Bitmap[] bottomToTops; //On constructor(colCount = 3) this.topToBottoms = new Bitmap[colCount]; // 3 this.rightToLefts = new Bitmap[colCount]; // 3 this.leftToRights = new Bitmap[colCount]; // 3 this.bottomToTops = new Bitmap[colCount]; // 3 In Kotlin(my try):...

Including a kotlin native .so in an Android application correctly I know how to build a native .so library targeting Android 32/64 bit, but I'm building it standalone inside my project. I'm guessing I can use swig or another wrapper to call into this through the jni and link the lib inside my jniLibs for my main app. I think this may work, but I won't have debugging support inside my app with this approach as far as I'm aware. I haven't seen to much info on doing this. The reason for trying this is kotlin native is going to be a lot more productive (and...

How to fix 'Unable to instantiate activity ComponentInfo' error with SoundPool I'm doing an Android Studio project in Kotlin where I want to include some music and sound FX with MediaPlayer and SoundPool. However, I'm having a problem with SoundPool that I can't solve. I would appreciate any help. The problem comes when I try to load sounds to SoundPool. I have followed Android documentation and some examples. Here's my code: var mediaPlayer : MediaPlayer? = null @Suppress("DEPRECATION") val soundPool : SoundPool = SoundPool(5,AudioManager.STREAM_MUSIC,0) val...

Some clear readable solution to how extend existing classes and interfaces in typescript, so I can get also auto import in webstorm I started developing web application in typescript and vue and found out that it's quite complicated to extend class so I do it by old java approaches like static methods and base classes but I am coming from kotlin and swift, objc world where I heavily use categories, extensions, well its basically the same concept. But in typescript I tried numerous examples that was quite difficult to write and with no luck , still had some problem with strict compiler. So in kotlin I can write somthing...

Is there plans to add Kotlin support for the Spring Tools Suite? I want to use Kotlin with the Spring Tools suite plugin for VSCode but it only supports Java (For things like intellisense). I know I should just use intelliJ and I will for now but I program in a lot of different languages daily and I would like to do all of this from the same tool.

Passing Variable to Interface Trying to pass the device ID to the interface and I am not getting anywhere. I essentially want to store the device ID to a variable and put it in the @Get for the interface. I tried using @Path but I am not familiar enough with it to use it. The url needs to look like this on the call http://xxx.xx.xxx.xxx/apps/api/109/devices/65?access_token=xxxxxx Interface interface DeviceDetailsAPIClient { @GET("devices/") fun getDevicesDetailsAsync(@Query("access_token") access_token:...

How to add new components on screen once a button is clicked? I am trying to create an IMessage looking application, once a button is clicked another label should be added to the screen. How can you do that in Kotlin? Or in Java, if it would be better in Java. buttonSend.setOnClickListener() { //createNewButton }

I have this RecyclerView and i want to read from realtime database i got stuck I'm trying to read data from firebase real time database in Kotlin. So i have this RecyclerView and i want to read an image, name, price. I thought it's possible to do it this way and just implement members of the object and call the data i want but i got stuck here help in kotlin would be appreciated this is the Recycler View where i want to read write the firebase read real time database photo,name,price package rakan.abc.monasabeh.Views import android.support.v7.app.AppCompatActivity...

The correct main method in Kotlin I am now learning Kotlin. Why is the parentheses underlined in IntelliJ IDEA ? When I remove the parentheses, the code is fine. May I ask why is this happening ? fun main(args: Array) //why is the parentheses underlined? { println("Printing Values") println("My hobbies are: ") println("1. Dancing") println("2. Learning") println("3. Watching Football") println("4. Volunteering") }

How to display a string with many lines in a Textview I am creating an about us section for my app and I am trying to display a text view with the our information on it. The problem is after I input the string into the text view it is all coming up as one line. The String I am inputting looks like this: "This is a test run , this string has many paragraphs Paragraph 1 Paragraph 2 " The output i am getting in the textview looks like this "This is a test run , this string has many paragraphs Paragraph 1 Paragraph 2 " How can i solve this...