How to fix "Object is not abstract and does not implement abstract member" error in Kotlin I'm currently trying to get into kotlin and I thought there is no better way to study it than running some apps written in kotlin. And so I found this sample project at https://github.com/Kotlin/kotlin-fullstack-sample and it gives me this error when I'm trying to run it I've tried to follow some step provided by the people who struggled with, what it seem to be the same problem, but it didn't help....

How to transition from one activity to another activity like left to right and right to left in" kotlin"? As I'm learning Kotlin for Android development, I'm now trying the basic programs like hello world and how to navigate from one activity to another activity , there is no issue in this. My concern is when I move from one activity to another activity it works fine but I do not move right to left and left to right

How can I navigate from drawerlayout to a fullscreen fragment using navigation controller? I have a recyclerview in a navigationview of a drawerLayoutFragment. I would like to open a new fragment containing itemDetails onItemClick. This itemDetailsFragment will have its own custom collapsetoolbar. I wish not to hide the toolbar of the drawerLayoutFragment onDestinationChanged since the animation while changing fragments will show that the toolbar is hidden before itemDetailsFragment has displayed. is there any way for itemDetailsFragment to navigate and show on top of...

Kotlin Application crashes when executing khttp.get function in Andriod Studio (Emulator and real HW) I'm trying to get a JSON object located at "https://jsonplaceholder.typicode.com/users/1" which contains { "id": 1, "name": "Leanne Graham", "username": "Bret", "email": "Sincere@april.biz", "address": { "street": "Kulas Light", "suite": "Apt. 556", "city": "Gwenborough", "zipcode": "92998-3874", "geo": { "lat": "-37.3159", "lng": "81.1496" } }, "phone":...

MutableList .clear() and adAll() behaves strangely Basically I'm using a method inside of a BaseAdapter to refresh it. It actually worked for plenty functions, however once I tried to implement a new one and used this its custom method to refresh it, it just cleared control MutableList. The control MutableList and the MutableList I'm passing throught the method is the same, however I highly doubt Kotlin would keep reference that deep. So I ended up placing logs everywhere and foud out, that the .clear() call cleared even the MutableList I'm...

Create file with UTF-16LE encoding I am trying to create a tab separate CSV via kotlin. For the requirement we need to have UTF-16LE for the produced file encoding. My stripped down code is something like this: import java.io.File import java.io.FileOutputStream import java.io.OutputStreamWriter fun main(args: Array) { try { val fileOutputStream = FileOutputStream(File("bla.csv")) val writer = OutputStreamWriter(fileOutputStream, Charsets.UTF_16LE) writer.write("bla\tbla\tbla")...

Android: Exoplayer - ExtractorMediaSource is deprecated I am following this tutorial to implement the Exoplayer. But the ExtractorMediaSource class is deprecated. I need to play video from a remote url. What is the alternative to use in this situation? val mediaSource = ExtractorMediaSource .Factory(DefaultDataSourceFactory(context, userAgent)) .setExtractorsFactory(DefaultExtractorsFactory())...

is it possible to trigger your app by voice command from anywhere? Is there any way to add some service, that will always be in background and will trigger my app on specific keyword? Just like 'ok google' but 'ok app'? And if no, can i add some service to app, that will always trigger by some commands? i'm working on alarm clock with voice control.

How to write extension function with nested generics? I have extension function on Single class: fun Single.checkResponse(): Single { return this.map { some code } } And trying to use it like: fun sign(body: Map): Single { return service.sign(body).checkResponse().map { it } } Service's sign signature: @POST(Urls.SIGN) fun sign(@Body body: Map): Single SignResponse inherits BaseResponse obviously Response is retrofit2.response And i've got an error: Type parameter bound for T in fun Single.checkResponse(): Single is not...

Kotlin, can I get if default argument is used in the function? I want to know if default argument is used. Something like: private fun createVideo(path: Url = DEFAULT_PATH, width: Int = 0, height: Int = 0) { if (path is default value) { // it means caller didn't set path return AVideo() else { return BVideo() } } I am handling this with function overloading which is unefficient.

ANR error occurs in the Coroutine in android I am using coroutinue in CoroutinueScope by Dispatchers.Default context. Sometimes, it occur ANR error, when not responding on long time(SEC 5). How to avoid this case. The requestWait function wait infinite time, I don't modify this function because of is a native method in android. And my device API level 21, very sad. connection: UsbDeviceConnection = null private fun workerTask(usbSerialDevice: UsbSerialDevice) = CoroutineScope(Dispatchers.Default).launch { while (isActive) {...

Unresolved reference: getPreferences I am trying to store a boolean value which is changed every time a button is clicked. I want to do this using shared preferences, however I keep running into this error: Unresolved reference: getPreferences This is my code: btnStyle.setOnClickListener() { styleHasChanged = !styleHasChanged; if(styleHasChanged == true){ btnStyle.setText("true") }else{ btnStyle.setText("false") } //...

How to get free and total size of each StorageVolume? Background Google (sadly) plans to ruin storage permission so that apps won't be able to access the file system using the standard File API (and file-paths). Many are against it as it changes the way apps can access the storage and in many ways it's a restricted and limited API. As a...

Parsing boolean from Firebase Database Snapshot I'm having issues pasing a Snapshot from the Firebase Realtime Database into a Data Class in Kotlin using ProGuard. Here's how the data looks in the Firebase console: Here's how I've modeled that data class In my android app: data class PickupCode( val code: String, val boxId: String, val orderId: String, val suborderId: String, val drawers: List, val isDelivered: Boolean ) {...

Is it possible to fetch/obtain KEY value of automatically generated args by navigation component? I warn if it is safe to use KEY as value names? For example, if there is long variable "id", then actually key becomes automatically "id" also, but in future if it will be safe?

Expose property from Android module to ReactNative I am writing Android native module for ReactNative. I exposed some methods using ReactMethod annotation. Is there any possibility to expose property, e.g: class MyNativeModule(reactAppContext: ReactApplicationContext) : ReactContextBaseJavaModule(reactAppContext) { override fun getName(): String = "MyNativeModule" @ReactMethod fun nativeModule() { Log.d("MyNativeModule", "Native module method") } val nativeModuleProperty = "I am a native property"

How to check if user with the email entered by user on the login form exists or not in firebase It's my first time I am working with firestore db. So I have this User class in my app: data class User( val name: String, val email: String, val standard: String, val formNum: String, val isVerified: Boolean = false ) Every time a new user registers, it save the data to the firestore database. I want to query when the user clicks the login button if a user with that email exists or not. I use the following code: db.collection(User.USERS_DB_NAME)...

Image View showing warning as unknown attribute android:contentDescription in AS 3.4.1 When I was update my Android studio from 3.3 to 3.4.1. I was face some interesting warning like In my Image View tag: android:contentDescription attribute is unknown. How I can resolve this warning? Or is it bug of new Android Studio 3.4.1?

App stops working on adding view created programmatically to expandable list view? I have set my layout to an xml which has ExpandableListView as root. Since, a scrollable view can't be put (or is very complex to put) inside another scrollable view, I have decided to put all the views I need alongside the ExpandableListView as its headers and footers. In my header, I have put 3-4 small LinearLayouts each having 1-2 TextViews. Everything works fine until here. Now, in my footer, I want to add a ListView like view, having about 3-4 strings. Because I do not know the size of...

Clicking on app name on the android notification Can clicking on the app name on the notification open the intent? Right now only when I click on the content area, I am able to open the app/intent. Below is my notification code incase needed. val notificationIntent = Intent(this, MainActivity::class.java) notificationIntent.action = ACTION_MAIN notificationIntent.addCategory(Intent.CATEGORY_LAUNCHER) notificationIntent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT or Intent.FLAG_ACTIVITY_SINGLE_TOP val...

Possibility of using java methods in kotlin I have method in java class that I need to use in kotlin. Is it possible? If so, how can I do this? my java class is EventCore, method name is setEvent

timer.start() not calling timer code in TornadoFX I used the TornadoFX tutorial to call a controller method from a View when a button is clicked (trying to us MVC instead of 1 massive view). A timer in this controller calls functions from a model which display video. The live stream image is no longer showing on the screen (javafx canvas) now that I am doing MVC paradigm. The view is successfully calling the controller using "inject()" and I see from the debugger the controller's init method being called which starts the timer, and all the...

Use jetpack navigation to display back arrrow in the action bar I have a jetpack navigation graph setup with bottom navigation and an action bar. The bottom navigation has 3 tabs. 1 of these tabs has a detailed fragment that I would like to display the back-arrow on in the action bar. In MainActivity onCreate(), I've added: supportActionBar?.setDisplayHomeAsUpEnabled(true) This displays the back button on every tab & fragment. How can I prevent display of the back button unless the user is navigated to a non-top level fragment? Is there a method that...

Where fragments should be created? In viewModel or Activity? I'm trying to learn MVVM pattern and i'm doing an example project with it. But I can't figure it out that fragments should be created in viewModel or Activity. I have created them in activity but whenever rotation changes it's all being recreated. This is my code: override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val navView: BottomNavigationView = findViewById(R.id.nav_view)...

Issue overriding onDrawerOpened I'm working on a Kotlin coded app using the Navigation Drawer Layout with a list of items. When I open the drawer using the icon at the top left I want it to notifyDataSetChanged so that the list is updated from outside the MainActivity. This includes pressing the back button, swiping open the drawer, or clicking the stacked lines icon at the top left Here's a simplified version of my code, but it's essentially a Navagation Drawer Activity for the context of my question: class MainActivity...

How to connect to Mqtt3AsyncClient using HiveMq-mqtt library? I have been trying to implement mqtt using hivemq in my Android app. Though I have used the same specs and configuration from their docs, I am still unable to establish a successful connection. I was able to use paho for mqtt earlier, but it doesn't work for android Oreo and above if the app is in background because the library didn't have startServiceForeground update. So moved to HiveMq. I am just trying their sample app using the quick start guides here. 1. <a...

Get data from a Firebase Firestore sub-collection This my project I have 2 RecyclewView, the first selects the user I want to manipulate, which is working perfectly. When selecting it I store your id and transfer it to a next screen that should show your medical history (using your id to search your database for your history). But this recycler view remains blank, does not give an error but also does not return anything, maybe I'm missing the time to put the path to be taken to bring this history. image BD Firestore: [1]: <a...

I used singpost for 4shared api, but got unAuthorized and 401 errors I am trying to make an Android app that downloads mp3 using 4shared api. I used singpost but it got unAuthorized and 401 error. Also some query url is possible but not api url such as download, thumbnails etc. var consumerKey = "xxxx" var consumerSecret = "xxx" val lm = LinearLayoutManager(applicationContext, LinearLayoutManager.VERTICAL, false) rv_list.layoutManager = lm var consumer: OkHttpOAuthConsumer = OkHttpOAuthConsumer(consumerKey, consumerSecret) val client...

Kotlin: How do I save the contents of an ImageView to the internal/external memory? So... I got this easy project where when clicking a button uses an intent to open the camera, take a picture, and if the user presses "OK" will display the photo image inside an ImageView, this is a fragment... On a button I call the camera intent and got the result URI in the image_uri variable, so I put this image in the ImageView object with: imageView.setImageURI(image_uri) Now, I want to save this image into the internal/external memory, or gallery. I saw many answers, and many...

android anr error Broadcast of Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010} "main" prio=5 tid=1 Native | group="main" sCount=1 dsCount=0 flags=1 obj=0x76024db0 self=0x7e75814c00 | sysTid=11665 nice=0 cgrp=default sched=0/0 handle=0x7efb8be548 | state=S schedstat=( 113364872507 54406457631 191892 ) utm=7848 stm=3488 core=2 HZ=100 | stack=0x7fd7d7f000-0x7fd7d81000 stackSize=8MB | held mutexes= #00 pc 000000000001f2ac /system/lib64/libc.so (syscall+28) #01 pc 00000000000228f4 /system/lib64/libc.so (__futex_wait_ex(void volatile*, bool, int, bool,...