why we can pass a contravariance in a covariance type example of the List in Kotlin I'm wondering why I can pass a contravariance in a covariance type example of the List I created this interface as you can see I is a contravariance but I was able to pass to the list interface ListMapper : Mapper if you check you will see that the list accept a Covariance type public interface List : Collection {...} Why and how can this be possible ?

how to make a group of radiobutton so that you can only select one? how to make a group of radiobutton so that you can only select one? i wanted to make only one radiobutton that is selectable

regex for removing special characters I need a kotlin function that will remove specific special characters from a string. The list of the special chars: []‘()*"' Data also contains \u0080\u0098\u0080\u0099 \u009F\u0091\u009F private val specialCharRemoval = "[‘()*’\\\"|\u0099|\u009C|']".toRegex() fun deaccent(keyword: String): String { keyword.replace(specialCharRemoval, "") } I tested String tokens = "\"book*‘\" ¼ ¶childΩ 7 â\u0080\u0098play* for| the â " + "future\u0080\u0099...

AnimationDrawable to Watch Face using Kotlin how are you doing? I'm trying to add a animation to a watch face that i'm making in Android Studio and i'm facing some issues. I'm totally new in this type of programming so if I say something dumb please correct me. First I learned how to draw a layout in the face canvas like this: inner class Engine : CanvasWatchFaceService.Engine() { private var myLayout: View? = null private var day: TextView? = null . . . override fun onDraw(canvas: Canvas, bounds: Rect) {...

background of my activity becomes transparent while closing the app I've created a calculator app, and it works fine, but there's one question - why the background becomes transparent when i close the app by performing home gesture? Here's how it looks: how to repair this? Thanks, any help appreciated. Here's the code for this UI, MDC Android:...

How to extract or save current song from MediaPlayer after changing speed or pitch in android I am currently developing an application to play music I have now added the feature of adjusting the speed and pitch for music in the my app fun MediaPlayer.setPlaybackSpeedPitch(speed: Float, pitch: Float) { try { if (hasMarshmallow()) { val wasPlaying = isPlaying; playbackParams = PlaybackParams().setSpeed(speed).setPitch(pitch) if (!wasPlaying) pause() } } catch (e: Exception) { } } But currently I want to extract music from MediaPlayer...

How to automatically pass an argument to a function when it is called implicitly kotlin maybe I phrased my question a little strange, but something became interesting to me. Let's imagine that I have some Extension function: fun Int.foo() { TODO() } Suppose that I need to pass the context of the Fragment from which I call it to this function, in which case I would do it like this: fun Int.foo(context: Context) { TODO() } Here we are explicitly passing the Context of our Fragment to the function. However, I'm interested in the question - is it possible to somehow change...

401 Unauthorized Error when trying to login Discord Bot with API Token I am trying to login my Discord bot to my server using the API token but I am getting a "401 Unauthorized" error. My bot is offline in my Discord channel and I can't seem to get it online. I have double checked that the token is correct and that my account has the proper permissions. Here is my code (I changed some letters and numbers in the token, so it is not a real token, but I am using a very similar one, I wanted to share a similar one to see if I am making a mistake here.):...

unable to read or write in android datastore I have a problem with android datastore. I dont know that I can't write or I can't read but it doesn't work any way here is my code: class DataStoreProvider(private val context: Context) { private val Context.dataStore: DataStore by preferencesDataStore("settings") private val phoneNumberKey = stringPreferencesKey("phoneNumberPreferencesKey") private val passwordKey = stringPreferencesKey("passwordPreferencesKey") fun readPhoneNumber(): String? { var...

How do I correctly initialise a property of type storage task in a kotlin class I have initialised a field called mUploadsTask and it is of type StorageTask. The class StrageTask has been imported but I am still getting an error on andoid studio. The error says: "One type argument expected for class StorageTask" My guess is that there is an argument I amm supposed to put in the class but I do not know what that is. Here is the line of code I had written: lateinit var mUploadsTask: StorageTask Please any suggestions would be fine thank you! I had tried rewriting it as...

Why does this clearly failing condition, not fail? While trying to debug a TextField issue, I noticed that onValueChange() was being endlessly called. I dug deeper and found this interesting condition. Value and it are the same object but the condition seems to succeed and lets onValueChange() be executed. Does anyone have insight on why this is the case? I didn't expect this condition to succeed. I haven't typed...

Roll two dice and get the sum I am using kotlin on android studio to make a dice rolling android app , it has two pictures which are the dice , a button to make you roll on two random dice numbers. I am trying to get a text view to display the sum of the two dice that were rolled. Can I get some help please . I have tried private fun rolldice2() { val dice = Dice(6) val dice2 = Dice(6) val yellowroll = dice.rollitMA() val yellowroll2 = dice2.rollitMA() val diceimage : ImageView =...

How can you pattern match for several types, one of which is required, ala rust enums? I need a variable, which can be one of several required values, of different types. (Let's say either a post, comment, or community) In rust, you're able to have enum data structures, which can have various types, then extract their inner info via a match statement: https://doc.rust-lang.org/rust-by-example/custom_types/enum.html The only comparable thing I've found in Kotlin, is the...

in_app_update:compileDebugKotlin error in Flutter build when debugging I had this issue when I try to setup my project on my new pc. FAILURE: Build failed with an exception. What went wrong: Execution failed for task 'in app updatecompileDebugKotlin'. A failure occurred while executing org.jetbrains.kotlin.compilerRunner.GradleCompilerRunnerWithWorkers$GradleKotlinCompilerWorkAction I tried to find the solution here and some says its because of the kotlin version <a...

what is the kotlin nested loop syntax issue? I am getting error for this syntax for (i in 0 until 8) { for (j in 0 until 8) { } println() } error is For is not an expression, and only expressions are allowed here. but this is valid for (i in 0 until 8) { for (j in 0 until 8) { } println() } only thing I changed was where println() is called, I have worked with java so I thought that placement should not matter. What is the issue here ?

How to insert image (Bitmap) to RTF file format and save to internally in android kotlin? I'm trying to insert image file to RTF file format and save to locally. Here, I've get the image from camera or gallery and convert that image to bitmap format. Now, I can try to insert this image to RTF file . This RTF file creation and save functionality I've done (.RTF extension) This way is correct or not, I'm not aware of it. If anyone know please share your points. Thanks.

Prevent other composables in a box to be focusable and clickable, Jetpack Compose When placing 2 or more composables in a Box() in jetpack compose, even if they overlap, they can be focused and clicked through each other, is there a way to prevent this behavior?

How to prevent of restore navigation graph? There are HomeFragment with HomeViewModel, HomeRepository and just SecondFragment that emit event to HomeRepository via singleton EventManager. Navigation graph * -> HomeFragment -> SecondFragment. When app was killed, Navigation Component restore graph to SecondFragment. In this case, HomeRepository don't created by HomeViewModel and emitted event by SecondFragment never collect. In case MutableSharedFlow with replay = 1 will be work. But all events will repeat. For example, shown toast...

Maven Kotlin plugin with JDK 17 not working upgraded Kotlin from 1.5 to 1.8 today: build fails in JDK 17 due to: java.lang.reflect.InaccessibleObjectException: Unable to make field protected java.io.OutputStream java.io.FilterOutputStream.out accessible: module java.base does not "opens java.io" to unnamed module @2ba9f986 at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354) at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)...

How can kotlinc without gradle or IntelliJ IDEA take less than 10 seconds to compile Hello, World? kotlinc -include-runtime -d hello.jar hello.kt takes over 10 seconds with the below hello word program. fun main() { println("Hello, world") } I have used oracle's and openjdk's java 17. I am using kotlin 1.80. I have tested it on two Linux machines. I have installed kotlinc using the source and using SDKMAN! I have 4gb of RAM. The same incredibly slow compile time results. When I compile using javac it is no more than a second for a far more complex project. Is there any way to speed up...

Ktor modify request on retry not working as expected I have a custom retry policy on receiving 5XX errors from the server. The idea is to retry until I get a non-5XX error with an exponential delay between each retry request also I would like to update the request body on every retry. Here is my code import io.ktor.client.* import io.ktor.client.engine.java.* import io.ktor.client.plugins.* import io.ktor.client.request.* import io.ktor.http.* import io.ktor.server.application.* import io.ktor.server.engine.* import io.ktor.server.netty.*...

Migration SharedPreference to PreferencesDataStore error on different type of values In my situation, the old app has a shared pref data saved as Int and I want it to convert it into a Boolean when updating it to the new project. Is there a way to catch that data when updating to the new app and converting it from Int to Boolean? (the int values are just 0 and 1) Old app: shared pref: "show_external_content" : '0' or '1' New app: pref data store: "show_external_content" : 'true' or 'false' If there is another solution besides catching the exception in Flow. Thanks in advance.

Escape triple quote within kotlin raw string I'm trying to create a raw string that contains three quotes in itself. The resulting string x should contain something like """abc""". I've been able to create the string with the following code, but was wondering if there's a simpler solution for this. val x = """${'"'.toString().repeat(3)}abc${'"'.toString().repeat(3)}"""

why don't getValue(nameClass ::class.java) work for me in Kotlin with Firebase in Android val data = FirebaseDatabase.getInstance() val refB = data.getReference("branches") refB.addValueEventListener(object : ValueEventListener{ override fun onDataChange(snapshot: DataSnapshot) { for(n in snapshot.children){ val branch = n.getValue(Branch::class.java) listB.add(branch!!) } } override fun onCancelled(error: DatabaseError) { } }) my class Branch class Manager(val id:String , val fName:String , val lName:String , val...

Meaning of this in Java (currently in Kotlin) I am looking at a class which goes like this: class temp(context: Context, attrs: AttributeSet) : LinearLayout(context, attrs), tempInterface { .................................. } I just wanted to ask, how can I translate this to Java? I have been able to do this as of now: public class temp extends LinearLayout implements tempInterface .................... public temp(Context context, AttributeSet attrs) { super(context, attrs); } .................... } In...

Jetpack Compose, recompositing doesn't work when the compose layout is not in the foreground Recomposition breaks if a view is added to the layout container from above. Situation: there is a profile screen, by tapping on the cell with the number, we load information in the back, whether the user can change the phone and, accordingly, turn the progress bar. If it cannot, we show an error (a custom view that is simply added to the very top of the container), after that the composition screen freezes and does not render changes, CircularProgressIndicator instead of hiding - just hangs....

I need to show profile image in round shape binding.appbar.groupImage.apply { shapeAppearanceModel = shapeAppearanceModel .toBuilder() .setAllCorners(CornerFamily.ROUNDED, 8f) .build() load(path) } *this is my xml and kotlin code for round image, * this is my output what I'm getting I need to show like this <a...

how to send arraylist request with object of string and image in android kotlin retrofit 2? Request payload --> { name:Employee one phone:9876543210 companyName:ows abn:ows1234 service:4 email:souravc+1001@pitangent.com licenses[0].license licenses[0].expDate:2022-12-06 insurences[0].insurence insurences[0].expDate:2022-12-06 type:INVITE locations[]:1 } licenses[0].license ----> this is file type licenses[0].expDate:2022-12-06 ------> this is string type We using retrofit library and my apiService class @Multipart @PUT("employees/{id}") suspend fun putEmployeeUpdate( @Path("id")...

Update RecyclerView from StateFlow doesn't work Is there a way to update (automatically) the RecyclerView when a list is populated with data? I created a simple app (here is the repository for the app). In HomeFragment there is a RecyclerView and a button to refresh the data. The app works fine as long as I have the following code in HomeFragment to update the adapter whenever the StateFlow list gets data. private fun setupObservers() {...

How do i read object from firebase in kotlin and android? How do i read object from firebase in kotlin and android ?? I tried this one val branch = n.getValue(Branch::class.java) And it didn't work for me