is dispatcher IO always run in IO.Thread? (android studio) I am learning coroutine with android. and i have curious dispatcher.io the book says like when i use withcontext(dispatcher.IO) OR lifecycleScope(Dispatcher.IO) it will run on IO.Thread. but other parts in book say multi-coroutines can run in main thread. dispatcher.io can run in main-thread(UI Thread in android studio)?

How do i run my Python Webscraping code with Kotlin Im working on a tool that downloads files from websites. I wrote a Python code for this now how do i execute this code with Kotlin? Are there any easy ways? (I have to do it in Kotlin but I don't know how to download something from a website so I use python) Thanks

StompClient Android fails to connect with SpringBoot server giving error "Expected HTTP 101 response but was '400 '" I am using the below library for StompClient implementation on my Android native code: StompClient Library It connects to the same URL with "HTTP" but when I use "HTTPS" mapping it doesn't connect and throws the below exception: Exception: java.lang.Exception: java.net.ProtocolException: Expected HTTP 101 response but was '400 ' Here is my code: private var stompClient: StompClient =...

How can i return list from override function? I have following code : val list = ArrayList() myRef.addValueEventListener(object: ValueEventListener { override fun onDataChange(snapshot: DataSnapshot){ for (s in snapshot.children) { val stock = s.getValue(Stock::class.java) list.add(stock?.token!!) } } override fun onCancelled(error: DatabaseError) { } }) list.forEach { ... but when i want to do something in...

Android InputLayout hint with dropdown not working I am trying to use TextInputLayout with a dropdown but I have a problem. The hint is not working, I mean it didn't go on the top like I expected. Here you can find my wrapper SelectorInputLayout and in my XML I have this following code : here you can see what I have What I expected is What is wrong with my code?...

How can I add data by data class which is in list which is in another list? Or is there a better way? This is my declaration: val areas = mutableListOf() My data class: data class Point( val accuracy: Double, val latitude: Double, val longitude: Double ) My attempt: areas.add(mutableListOf(mutableListOf(Point[0].copy(accuracy = 0.0, latitude = 0.0, longitude = 0.0))) This maybe can help to understand what I need: <a href="https://releases-f89f5.firebaseio.com/.json?fbclid=IwAR3Zso66lLJLQDX17K5LFuqByaJFLmKahg-TYrJF3BAZqhd3CbtFgqo9tug" rel="nofollow...

Save List &lt;Uri&gt; inside the object This is object class data class SavedInfo( val uris: ArrayList, ) : Serializable onSaveInstanceState method override fun onSaveInstanceState(outState: Bundle) { super.onSaveInstanceState(outState) val savedInfo = SavedInfo(uris) outState.putSerializable("uris", savedInfo) } Get instance if (savedInstanceState != null) { val savedInfo = savedInstanceState.getSerializable("uris") as SavedInfo }

Execution failed for task ':app:lintAnalyzeDebug' Currently I have stuck on this exception. When I build the kotlin application in Android studio then it works perfectly fine... but in github actions the gradle workflow gives this error. I have tried also tried to do the following in app level build.gradle > android > lintOptions checkReleaseBuilds false abortOnError false But all these solutions doesn't work for me.

My app doesn't display the data from an API with retrofit and moshi I am a beginning computer science student. For school I have to make an app that can display data from an API. I use this API: http://openlibrary.org/search.json?q= The user of my app has to enter a booktitle or author, so they can find a book. I add the search value to the url. For example, if I want to search "The hobbit", the url would look like this: <a href="http://openlibrary.org/search.json?q=the%25hobbit%22"...

Share Attribute Validation Annotation between different Models I have multiple Models with the same attribute, for example: CustomerNumber it hast to be always 10 digits long, it is now in the Model of Customer, CustomerContract, CustomerContactData, Entity and Restmodels. I am looking for a possibility to define the Attribute validation only once. I am using Springboot and Kotlin. ( Value Classes do not work because Spring ignores init and anotations of them on RestController )

How can I solve nullity error on kotlin while using EditText? Complete beginner, trying this on kotlin. I am trying to capture a photo and save it and then load it on room database. I also need tag the photo and load it according to that. But there is an error like "Caused by: java.lang.NullPointerException: findViewById(R.id.metin) must not be null". How I can solve it? Thanks in advance. class MainActivity : AppCompatActivity() { private val cameraRequest = 1888 lateinit var imageView: ImageView lateinit var textbox : EditText...

How to find the reasoning behind IntelliJ Kotlin lint check I received a lint message while writing Kotlin using IntelliJ as my IDE: The argument can be converted to 'Set' to improve performance My code went something like this: val variable3 = variable1 - variable2 variables are of type List The linter recommended me to change it to val variable3 = variable1 - variable2.toSet() I would like to find out why it recommends this change and where the documentation is so next time I can look up the messages and learn the reasoning behind the lint check.

java.lang.IllegalArgumentException: Expedited jobs cannot be delayed Hey I am working WorkManager in kotlin. I didn't understand some code and getting me this error. Could you someone explain me in more details. 2022-01-06 164833.501 14483-14483/com.example.app E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.app, PID: 14483 java.lang.IllegalArgumentException: Expedited jobs cannot be delayed at androidx.work.WorkRequest$Builder.build(WorkRequest.java:326) at...

Android-Image-Cropper example in java I want to use Android-Image-Cropper library in my project. I'm using java language but the library's document provides examples only in kotlin. Can anybody provide me an example of using this library in java? (I want to use "Calling crop directly" section) github link of the library: https://github.com/CanHub/Android-Image-Cropper Thank you

Android Kotlin - Parse through all active holders because ExoPlayer keeps playing on RecyclerView destroyed When I close an activity which has a RecyclerView with items containing ExoPlayer then I can still hear the the audio of the videos I'm saving the ExoPlayer objects as tags inside viewHolder: holder.vidPlayer.setTag(mpTag, player) so I need to parse through all active (or also inactive would be ok I guess) holders to reach the players and release / nullify them before the activity gets destroyed. I need to do this from the activity, so as pseudocode: override fun onDestroy() {...

Inserting data to the room database from the adapter class crashes the app So I've been trying to insert data to the room database from the adapter class when an onclicklistener event happens. But everytime I do that my app crashes without any error message in the logcat. The only thing that happens in the event is that the database instance gets created and as soon as that happens the app crashes. My item class : @Entity(tableName="item") data class Item( @PrimaryKey(autoGenerate = true) val id: Int = 0, @ColumnInfo(name = "path") val path:...

Android-Kotlin- button acting as back button How do I make an on-screen button act in the same way as a physical/virtual back button? Kotlin, not Java please. I know this is just duplicating a function, but this is precisely my goal here. I'm trying to learn basics of Kotlin for android apps (Android Studio), to satisfy my curiosity and maybe also do something good for neurodegenrative disease patients. Thanks to Internet help, I got a standard, goto new activity button working (example below), but I'm stuck on that one. val button:...

Error "imageView.drawingCache must not be null" in Kotlin Absolute beginner in Kotlin. I am trying to capture a photo from camera and save & load it to room database. Capture button works fine but save & load buttons just crash after clicking them. There is an error "java.lang.NullPointerException: imageView.drawingCache must not be null", any idea what must be the problem? Thanks in advance, it is appreciated. class MainActivity : AppCompatActivity() { private val cameraRequest = 1888 lateinit var imageView: ImageView...

How to delete element of an array in Firestore? I want to delete some element from "groups" array in User collection. Firestore structure: My current sollution is not working: suspend fun leaveGroup(groupId: String, user: User): Boolean = suspendCoroutine { continuation -> val group = hashMapOf( "/Groups/$groupId" to FieldValue.delete() ) db.collection("Users").document(user.id) .update(group)...

How to fix IFCMService Failed to send notification in my Android App Can anyone explain to me why the data orderStatus is updated in my client app but my server app keeps getting the "Failed to send notification" when I'm updating the order. I'm building a food ordering app. Thank you! This is my code for updating the order status in my Server App. I inserted the code where to send the notification in onDataChange: private fun updateOrder(pos: Int, orderModel: OrderModel, status: Int) { if (!TextUtils.isEmpty(orderModel.key)) { val update_data...

Error testing firebase login with Mockito I have login form which sign in the user using firebase and i'm trying to test the login functionality by writing some code and i used Mockito to mock the firebase class but for someone it keeps failing and i think there is something , if someone could help fix the issue , Thank you This is my code @RunWith(AndroidJUnit4ClassRunner::class) class LoginActivityTest { @get:Rule var scenario = ActivityScenarioRule(LoginActivity::class.java) private lateinit var emailEditText :...

How to polymorphic deserialize a class based in two properties? I'm having problems trying to deserialize from json string into the correct object since I have to check 2 properties before deserialize to the correct class, ie: { "org": "Company1", "event_type": "REGISTER", "day": "2021-01-01", "data": { "name": "Kyore", "age": 10 } }, { "org": "Company2", "event_type": "REGISTER", "day": "2021-01-01", "data": { "name": "Casky", "age": 12, "lastName": "Kyky" } }, { "org": "Company2", "event_type": "DELETE",...

My app keeps crashing when i try to search for users My app always crashes when i try to search for users. logcat directed me to a line in my search fragment but i do not know exactly what to do private fun searchUser(input: String) { val query = FirebaseDatabase.getInstance().reference .child("Users") .orderByChild("fullname") .startAt(input) .endAt(input + "\uf8ff") query.addValueEventListener(object: ValueEventListener { @SuppressLint("NotifyDataSetChanged") override fun...

"Hey Google, Open x" works on Pixel but not Samsung I have an application that is function complete and is available on the Play Store. The issue is that when I say "Hey Google, open " it works on a Pixel device but not on a Samsung device. Other applications (Spotify, etc.) open just fine on the Samsung device. This was written in Kotlin for reference and I'm wondering if there is a setting in AndroidManifest.xml that might be incorrect. I've been fighting with this one little issue for hours so any suggestions are appreciated.

Kotlin/Native adding c library ncurses via Cinterop I have been trying to add ncurses to Kotlin/Native using cinterop, but this error shows up: Exception in thread "main" java.lang.Error: /usr/include/stdint.h2610: fatal error: 'bits/libc-header-start.h' file not found I checked and I have this file installed in this path. this is my code: src/nativeInterop/cinterop: headers = ncurses.h headerFilter = ncurses.h compilerOpts.linux = -I/usr/include -I/usr/include linkerOpts.linux = -L/usr/lib64 -L/usr/lib/x86_64-linux-gnu -lncurses...

How can I discover network services with Kotlin for Desktop? I am developing an app for Android and Debian distributions that allows the user to send and receive files over the network. To achieve this I chose Kotlin and JetBrains' Compose for Desktop to create the Debian app. However, I could not find a proper way to discover services on the network using Java. For Android, I am using the Network Service Discovery API that is already built-in....

Kotlin field Assignment via Scope Function (Apply ) What is the difference between two such field assignments? Actually, the first way seems very readable but I come across second way in many sample codes. Is there a special reason? class Login { var grantToken = GrantTokenRequest() fun schema(schema: String) { this.grantToken.schema = schema } } class Login { var grantToken = GrantTokenRequest() fun schema(schema: String) = apply { this.grantToken.schema = schema } }

Timer implementation in Android on Koltin: Should one use coroutine with delay or CountDownTimer As per the commentary of this answer, using CountDownTimer val timer=object:CountDownTimer(Long.MAX_VALUE,10){ override fun onTick(p0: Long) { _mutableLiveData.postValue(newValue) } override fun onFinish() { TODO("Not yet implemented") }...

Web camera video capture kotlin I need to create a webcam video capture. For this purpose, I follow the lesson. I have a problem with setting

Transform Map Values to Data Class in Kotlin I have a map whose values are an arraylist of different object types (LocalDate, LocalTime, Float, List(Float)). I would like to transform the map values to a custom data class i have created. I have tried destructuring the maps value components however i am getting error "Destructuring declaration initializer of type Map.Entry must have a 'component3()' function". How would i perform this transformation below? Blockquote val localDate1 = LocalDate.now() val localTime1 =...