user?.uid keeps getting sublined because of '?" So i'm building a login app based on this tutorial https://codigofacilito.com/videos/login_en_android_con_firebase_usando_kotlin_bytes and I ran into this error which I find pretty weird being a very simple line of code. It sublines it calling for a String instead of "String?". Then when i erase the ? it sublines the dot calling for the secure character "?" . The line...

Updating user profile photo does not update it with currentUser.photoUrl I have take a photo, then I update my current user photo to apply this change to the Firebase authenticated user. What I spect is after updating this photo to the authenticated user, to get the photoUrl as a string like when I first sign in in my app suspend fun updatePhoto(uri: Uri): Resource{ val currentUser = FirebaseAuth.getInstance().currentUser val profileUpdates = UserProfileChangeRequest.Builder().setPhotoUri(uri).build()...

Java variable in interface in Kotlin way I am interesting are there any way to replace kotlin interface variable in Java. E.g. what should i write in java to have same logic interface ObjectWithId { var id : Long } Before facing this problem all my code could be easily converted back to java, but using interface variables breaks 'backward compatibility'. Isn't it?

Kotlin: generic cast function parameter Taking my first steps in Kotlin, I'm struggling to find the correct signature for a function that receives an instance of a known class along with the desired output class and then looks in a map of converter lambdas whether the conversion can be done. Here's an example for Long: private fun castLong(value: Long, clazz: Class): T { // map lookup removed for simplicity return when (clazz) { String::class.java -> { value.toString() } else -> {...

Clicking on the First Item on BottomTabBar Navigation Does Not Work on Android I am using Android Jetpack with Kotlin to create this BottomBarNavigation UI using NavigationHostFragment, Navgraph and NavController. I have 3 tabs and everything works as expected except when I try to click on the first tab, it does not do anything. Got stuck for a few days. Can't find the issue. Any ideas? bottom_tabbar_nav_graph.xml bottom_tabbar_menu.xml activity_main.xml MainActivity.kt private fun setupNavigation()...

Duplicate a nested Map to a MutableMap in Kotlin Given a nested immutable map of: val someNestedMap = mapOf( 2 to mapOf( "a" to true, "b" to false, "c" to true ), 3 to mapOf( "d" to false, "e" to true, "f" to false ) ) If I want a new copy of this exact structure, but with each of the maps to be mutable, is there an easy way to do this in Kotlin? I want to create a copy of the above as val newCopy: MutableMap

NewApi lint different behaviour The code where min api level is 21: interface SampleInterface { fun interfaceFun() { val value = HashMap().getOrDefault("a", "b") } companion object { @JvmStatic fun companionFun() { } } } IDE sees two issues: getOrDefault requires api level 24 @JvmStatic for companion method also...

What are the technical pros and cons of using Python or Kotlin/Java for cross-platform desktop applications? [closed] I'd like to make smooth and performant cross-platform desktop applications that aren't web-based (Electron) or developed in C/C++. I've narrowed it down to Python, either with wxPython (Phoenix) or QtPy, and Kotlin with TornadoFX. The applications would be complex with custom UIs, such as many popular websites (Spotify, YouTube, Reddit, etc.).

time series test data in Kotlin Android phone app I'm just learning Android development! I'm writing a demo in Kotlin to run on an Android phone The Android Activity is going to display data To simulate the data source (as yet to be determined), I am trying to make a Service which generates data once a second and passes it to the Activity Questions Is there already something that does this? if not, I have to write it - would this be a Service? how does the Activity connect to the Service? Or does it? how does the Service update the...

How to decrypt an encrypted file correctly? I use the cryptography library: androidx.securitysecurity crypto1.0.0-beta01 according to this example https://developer.android.com/guide/topics/security/cryptography I cannot correctly decrypt the file I encrypted. After decryption, all pages of the pdf file are blank. the screenshot shows the file size changes. Can anyone tell me what I'm doing wrong? <a...

how to set the dependencies of bottom layer android library from top layer Android Project? I have an Android library which acts as a service and has some personality such as receiving notification, sending notification delivery message to server, etc. This library is dependent to some data like `server url', 'the state of user logging' and some other data. Now my problem is what is the best design to set those information to this library from the top layer Android Project(the project that uses this library). For now I have declared setter methods and set the data which is required...

example, design pattern for recurring job in Kotlin Android phone app? I'm just learning Android development! I'm writing a demo in Kotlin to run on an Android phone I want to make a background (process?) that sends simulated data, once per second, to the Activity Question: Is there an example of this somewhere? questions I'm trying to answer: would this be a Service? how does the Activity connect to the Service? Or does it? how does the Service update the Activity? how does the Service know when to run (the scheduling)?

Kotlin dynamic for JVM vs Reflection If ever Kotlin JVM would have the dynamic type (Similar to Flutter's dynamic type): What would be your use case for using it? When should you use dynamic and when should you use reflection? When is it recommended to use reflection in Kotlin? Currently it only supports the JS counterpart as stated here https://kotlinlang.org/docs/reference/dynamic-type.html In Kotlin if it supported dynamic for...

How to return value from async coroutine scope such as ViewModelScope to your UI? I'm trying to retrieve a single entry from the Database and successfully getting the value back in my View Model with the help of viewModelScope, but I want this value to be returned back to the calling function which resides in the fragment so it can be displayed on a TextView. I tried to return the value the conventional way but it didn't work. So, How Can I return this value from viewModelScope.launch to the calling function? View Model fun findbyID(id: Int) {...

Unable to mock data to test Usecase class I'm writing a unit test for one of the Usecase classes. The android project contains both Java and Kotlin code. Here is the relevant Gradle dependency snippet testImplementation 'org.robolectricrobolectric3.7.1' testImplementation 'org.mockitomockito core1.9.5' The usecase authenticates a student and returns valid tokens by calling the repository instance for network operations. What I'm doing in the Usecase test class is that I mock the data returned by the repository so that I can...

OneTimeWorkRequest JobCancellationException Returning state WorkInfo.State as ENQUEUED Although coroutine Worker was cancelled with the following exception. (kotlinx.coroutines.JobCancellationException: Job was cancelled) i"m still receiving WorkInfo.State as ENQUEUED instead of CANCELLED, not sure why? and I am using OneTimeWorkRequest

Will I always add withContext(Dispatchers.IO) in suspend when I pull data from a remote server? I'm learning Coroutines of Kotlin. The following content is from the artical https://developer.android.com/kotlin/coroutines. Important: Using suspend doesn't tell Kotlin to run a function on a background thread. It's normal for suspend functions to operate on the main thread. It's also common to launch coroutines on the main thread. You should always use withContext() inside a suspend function when you...

How to load a fragment only once when the app is opened for the very first time I am using Navigation component and Kotlin. What i want to make is a log-in fragment that will only load once when the app is opened for the very first time, and never again. The perfect example of this will be Facebook log-in activity. I haven't written any code at the moment cause i have no idea about how to start with this,so can't provide any code snippets, apologies.

Android Bubbles I try this sample https://developer.android.com/guide/topics/ui/bubbles. Add the bubble notification in my Project. But it not working. I want test the bubble is work or not. So bubble Activity just a empty. In the onCreate function I will create a notification channel. private fun createNotificationChannel() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { val name =...

How does performance, CPU and RAM usage, and scalability differ between Python and JVM desktop applications? Trying to decide on an Electron alternative. I'm going to use TornadoFX for the GUI if I go the Kotlin route, and wxPython or QtPy if I go the Python route.

Kotlin, Parsing generic JSON I try to make a framework function where an application can specify a type of list. The function should handle all parsing and all that the app has to provide is the type of line that should get parsed. It should more or less look like this: val personsInHousehold = getArrayInput( PossibleParameters.persons ) But with Klaxon, I cant transmit the type through a function as it seems. protected fun getArrayInput(keyword: Any): List{ val jsonString = data.getDataByKeyword(...

Grade sync failed: Unresolved dependencies I tried to sync my project in android studio with gradle files but it failed and I got the above message "Grade sync failed: Unresolved dependencies". I also got these errors in the build tab: ERROR: Unable to resolve dependency for ':app@debugUnitTest/compileClasspath': Could not resolve androidx.fragmentfragment[1.2.0]. Show Details Affected Modules: app ERROR: Unable to resolve dependency for ':app@debugAndroidTest/compileClasspath': Could not resolve...

Flyway Doesn't Close Connection After Calling To connection.close I'm using flyway in my application. Whenever the application loads, I'm calling the flyway.migrate() function. After my application starts up i don't need flyway for any further task therefore I would like to release this resource and close the connection. the following block describes what I'm trying to do: fun initFlywayAndMigrate() { val flyway = Flyway.configure() .dataSource( "jdbc:postgresql://host:ip/db-name", "user"), "password")...

Paging Library Error ,Couldn't retrieve data from Firestore I tried retrieving data from Firestore using Paging Library . The app works but is not able to fetch Data from the database.I am not able to find any errors in the code . If anyone can help . your help is appreciated.Below is the code. Model Class Note import androidx.lifecycle.ViewModel import androidx.lifecycle.ViewModelProvider import java.lang.IllegalArgumentException class DataFactoryRepository(private val dataRepository: DataRepository) : ViewModelProvider.NewInstanceFactory() {...

Can anyone point out the issue with my code? My code passes all the tests but when I attempt the kata it fails and shows the error expected: but was: My code: import kotlin.math.pow fun digPow(n: Int, p:Int): Int{ val nStr= n.toString() var pow=p var store=0 for (i in 0 until nStr.length) store += Character.getNumericValue(nStr[i]).toDouble().pow(pow++).toInt() for(i in n-1 downTo 1) if (i*n==store) return i return -1 } Link of the kata: <a href="" rel="nofollow...

Android Multi-row summation: Request for code shortening I have a table with fifteen rows. Each row have three columns and a total column. I want to get the total per row, the grand total, and the overall average. The user may not enter data for all rows, and the user may skip a row. So the code checks if the user have entered data in one of three fields of each row. If the row is blank, ignore it. If some of the fields are filled-up, tell the user to fill up the rest of the row. If all the fields in a row is filled up, sum all its fields and...

What is causing this LinearLayout casting error? I'm learning Kotlin after exclusively working in Java previously, and I've run into a bit of a confusing error that I can't seem to fix. I tried to implement a RecyclerView, and every effort I've made has failed. I even copy\pasted the code from the developer page to see what I am doing wrong, only to run into the same issue. It's been hours at this point and I'm stumped. Why am I...

Problems with mutable sets in Kotlin I've recently started learning to program in Kotlin. As I tried to add a sequence of numbers to a mutable set using the for loop, the corresponding ASCII value was being added instead. fun main(args: Array) { var userInput = readLine() //The input was 12345 var set = mutableSetOf() for(n in userInput.orEmpty()){ var numN = n.toInt() set.add(numN) } println(set) } // The output is [49, 50, 51, 52, 53], whereas I expected [1, 2, 3, 4, 5] At first I speculated the problem to...

how to make a scroll Linstener and scroll finished moment for webView in android (Kotlin) if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { mWebView?.setOnScrollChangeListener { v, scrollX, scrollY, oldScrollX, oldScrollY -> Log.w("TAG", "scroll pos ==> $scrollX $scrollY") } }

set initial value to time piker I want to set initial value to time piker import android.os.Build import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.widget.TimePicker import androidx.annotation.RequiresApi class MainActivity : AppCompatActivity() { @RequiresApi(Build.VERSION_CODES.M) override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) var periodTimePiker: TimePicker =...