RxKotlin "withLatestFrom(...)" compile error: not enough information to infer type variable R 1) The code below fails to compile with an error: "not enough information to infer type variable R" keywordChanges .withLatestFrom(searchParamsSubject) .subscribe { (keyword, searchParams) -> ... } 2) The code below compiles and works, but I would prefer not to have an empty subscribe() and not to put side effects into the combiner function. keywordChanges .withLatestFrom(searchParamsSubject) { keyword, searchParams -> searchParamsSubject.onNext(searchParams.copy(keyword...

Kotlin - Declaring a variable which is an array list of hash maps where key is string and value is another array list as the title says, I wish to create a variable which is an array list of hash maps where key is a string and value is another array list of objects of custom class. In Swift or other languages it will look something like this: [String: [MyClass]] In Kotlin I tried: var testVar = ArrayList I am seeing error like "Expecting a '>', Property getter or setter expected". What am I doing wrong here?

Kotlin Coroutines - unlimited stream to fan out batches I'm looking to implement a pipeline for processing an infinite stream of messages. I'm new to coroutines and trying to follow along with the docs but I'm not confident I'm doing the right thing. My infinite stream is of batches of records and I'd like to fan out the processing of each record to a coroutine, wait for a batch to finish (to log stats and stuff) before continuing to the next batch. -> process [record] \ source -> [records] -> process [record] -> [log...

i don't undertsand how these two line of kotlin code work class MainActivity : AppCompatActivity() { private lateinit var binding: ActivityMainBinding private val myName:MyName = MyName("Kotlin noob") override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) binding = DataBindingUtil.setContentView(this, R.layout.activity_main) binding.myName = myName //line 1 binding.doneButton.setOnClickListener { addName(it) } } fun addName(view: View) {...

SQL how to find first appearance of certain value I have DB like this: id:0 Type: 1 Text: someRandomText46 id:1 Type: 2 Text: someRandomText71 id:2 Type: 1 Text: someRandomText28 id:3 Type: 2 Text: someRandomText34 id:4 Type: 2 Text: someRandomText10 id:5 Type: 1 Text: someRandomText83 id:6 Type: 2 Text: someRandomText91 id:7 Type: 2 Text: someRandomText35 id:8 Type: 1 Text: someRandomText85 I need to display to user all lines of DB (of type 1) one by one. This means that user sees inside of app all information which is presented inside...

SAM Conversion with Generics I have my interfaced defined like so: interface OnItemClickDelegate { fun onItemClick(entity: T?) } Right now I have my interfaced defined anonymously in a different class: var itemClickDelegate = object : OnItemClickDelegate { override fun onItemClick(entity: Derived?) { doSomethingWith(entity) } } This compiles fine, but when I switch it to: var itemClickDelegate = OnItemClickDelegate { entity -> doSomethingWith(entity) } I get a compiler error...

Using Kotlin execute sql scripts against database table I have in MySQL database a fixed table, just one table. I want to run many SQL statements against this table and get back the results. I have a directory folder with many sql script files. I want to be able to loop thru the files in the directory and execute them against the MySQL database table. I have looked all over and saw there was something kind of done in Java about this, but it seems problematic. SO i am hoping that another JVM language like Kotlin can do this functionality....

Animating recyclerView items I'm applying some AnimatorSet to the items of a recyclerView, recyclerView adapter: class MyAdapter(...) : androidx.recyclerview.widget.RecyclerView.Adapter() { override fun onCreateViewHolder(parent: ViewGroup, p1: Int): ViewHolder { return ViewHolder(...) } override fun onBindViewHolder(p0: ViewHolder, p1: Int) { p0.bind(...) } inner class ViewHolder(itemView: View,...) : androidx.recyclerview.widget.RecyclerView.ViewHolder(itemView) { fun bind(...) { ......

Android Studio: Passing a value from editText to the URL for calling the server I need to pass a value that I obtain from an editText in the URL that I use to call the server. If my localhost is "x.x.x.x:xxxx/", the value that I need to pass is "id"(from the editText) so, building them together, I will obtain this URL "x.x.x.x:xxxx/id". In conclusion, I need to modify the link that I call by adding the id that is inserted into the editText, for having different data based on the id.("x.x.x.x:xxxx/0876", "x.x.x.x:xxxx/8907", "x.x.x.x:xxxx/3456", etc...) Please I need...

how to display an alert dialog using addproximity from a markup within onmapready? kotlin google maps how to display an alert dialog using addproximity from a markup within onmapready? simple alertdialog. using map radius, thanks any help is welcome. using kotlin my onmapready override fun onMapReady(googleMap: GoogleMap) { Log.i("MAP READY", "READY") val position = if (currentLocation != null) LatLng(currentLocation!!.latitude, currentLocation!!.longitude) else Utils.vienna this.map = googleMap...

"Property must be initialized or be abstract" in init block when throwing an exception Why does kotlin report Property must be initialized or be abstract. The object construction is never finished, so it should not matter whether a is initialized or not. Could a case be demonstrated where this would be a problem? class Foo { private val a: Int init { a = 42 throw Exception() } } fun main() { Foo() } kotlin playground However this works just fine class Foo {...

How to inherit generic types in implementations without having generic interfaces in Kotlin? I'm writing this SDK where I need to define functionality in publicly accessible interfaces as: interface CommonEndPoint { fun doSomething(listener: IListener) } and then implement the common interface in the sub-project as: interface SpecialEndpoint : CommonEndpoint { fun doSomething(listener: IListener) } where SpecialType extends CommonType. I have defined the contra-variant generic listener as: interface IListener { receiveResult(result: T) } The problem is: I need the...

How to properly construct Room Entities with Inheritance I have a list of fields I would like every entity to have, so I've created a Base Entity. open class Syncable( @ColumnInfo(name = "id") var oid: String? = null, @ColumnInfo(name = "created") var created_on: Long = System.currentTimeMillis(), @ColumnInfo(name = "updated") var updated_on: Long = System.currentTimeMillis()) Then I have a number of entities inheriting from this one, like: @Entity(tableName = ProfileContract.TABLE_NAME, indices = [Index(value = ["id"],...

can someone explain this for loop code trying to learn and not getting it fun sum(number: Int) : Int { var sum = 0 var i = 0 while (i

How to auto call function in Kotlin for every function call within a class I have a class with multiple functions class Foo() { fun one() { //do something } fun two() { // do something } fun three() { // do something } } How can I trigger a call to a Logger object that I have, so that in the logs I can see all functions accessed or called, without explicitly placing the log call on every function to keep the code clean. I'm trying to keep a full log trace of all functions called within a service api call, but I...

why am I getting Error: Variable expect in kotlin? I am trying to write a function to find the majority element in kotlin but when I compile the code I get variable expected error on the following line map[key]?.let{ value-> Below is the function which I am trying to run. I am new to Kotlin and not sure why I am getting this error. fun majorityElement(nums: IntArray): Int { HashMap().let{ map -> nums.forEach{ key-> map[key]?.let{ value->...

How to edit current theme or create new theme to follow API response in Android The situation is if I want to make my app to retrieve theme's attrs value from API's response and apply that value instead of the default. Imagine the LINE application that allows you to download the theme and use it permanently. I want to know how to do it in a proper way. P.S. I don't want to pre-define the theme in XML. I want my theme to use values that responded from API.

Why retryWhen hides errors from handler if subscribed in background? I got retryWhen usage which is needed to do some request in case of server error. This is simplified by such synthetic code: fun main(args: Array) { Single.error(Exception("Source")) .retryWhen { it.flatMapSingle { Single .error(Exception("Handler")) .subscribeOn(Schedulers.computation()) //.observeOn(AndroidSchedulers.mainThread())...

To how convert object to ByteArray and the encode with Base64 URL_SAFE in Swift? In Android, I could convert an object to ByteArray and then encode it to Base64 (URL_SAFE) as per code below val myByteArrayObject = myObject.toByteArray() val meEncodedObject = android.util.Base64.encodeToString.encodeToString( myByteArrayObject, android.util.Base64.URL_SAFE).trim() How could I achieve that in Swift?

How to Post complex datas as MultiPart using Retrofit in Android? I have data which is Array of Json Objects, I need to pass this as MultiPart Form Data. The data which i need to post is below : { "name": "KIMS EKM", "latitude": "8.5605418", "longitude": "76.8810471", "state": "Kerala", "district": "Thiruvananthapuram", "city": "Leela Infopark", "landmark": "Kazhakuttom", "phone": "7293318484", "email": "aswin.as@velosit.in", "admin_name": "Aswin", "admin_phone": "7293318484", "admin_email":...

How to make scaling animation on transformable node in ARCore android? I am trying to add scaling animation to Transformable Node (3D model) when I tap on it. Can anyone help me with its code?

Arraylist of multipart data send to server in JsonArray format retrofit I need to send multipart data in an array format and I made a request bean. data class ProviderDocument(@SerializedName("document") var document: MultipartBody.Part?=null, @SerializedName("document_id")var document_id: RequestBody ?=null, @SerializedName("unique_id")var unique_id:RequestBody?=null, @SerializedName("expires_at")var expires_at:RequestBody?=null) { } Adding data in Arraylist...

Display over other apps I am facing issue while open image picker in android getting error is -> Display over the apps . I am trying to enable it but my phone is not allowed to toggle . I am using one plus 6 and android version is 9(Pie) . can you please help me solve this error . Is there any code required to do for this . here is an image to shows an error.

ReactiveMongoRepository not saving my data I am noob in spring and mongo and noSQL. I have connected to my mongoDB on local. However my attempts to save my entity keeps failing. val a0 = myEntity(name = "my Entity") repository.save(a0) My repository extends ReactiveMongoRepository. But when I change it to extend MongoRepository, then it works. What possibly could be the problem? My database instance is running and working fine. I am guessing that it has to do something with reactive things.

How to use double tap to wake and lock smartphone screen? I'm new to gestures and I'm new to kotlin, so I thought of developing a gesture app and I decided to develop an app that wakes the lock screen on double tap and lock the screen on double-tap. So, it would be great if you guys share any experience in this, so it will be helpful for me to get a head start. Many Thanks.

How to copy companion object and make changes without reflecting these changes to the original object? I am using companion object to temprorarily save some data. I might want to change this data and also i want to make sure that original object is not changed when i make changes. I tried this. companion object{ var position: Int = 0 } var copyPosition = positon copyPosition-- println(copyPosition) This works perfectly fine and prints -1. Original position is not changed. (value 0 is not changed.) However, the same operations with List is not working. companion object{...

EditText.selectAll() doesnt select text First of all, if anything can be better in my question, please let me know, it's my first one here. I am building an app for android. I want my users to be able to quickly enter a time in an edittext field. There usually already is a time in there, which should be selected so any input from keyboard will result in it being overwritten, while just hitting "next" (or enter on keyboard" will leave it the way it is and jump to the next field. For all my fields this works nicely, but for some...

Kotlin: Unresolved reference: FieldCoordinates,GraphQLCodeRegistry can't find the reference FieldCoordinates, GraphQLCodeRegistry in graphql-java package

Spring data ldap - query user direct reports? Is there a way to retrieve all direct reports for a given user? I have an Entity: @Entry(objectClasses = arrayOf("person", "organizationalPerson", "top", "user")) class LdapUser { ... } and Repository: @Repository interface LdapUserRoRepository : LdapRepository { @Query("(mail={0}*)") fun findUsersByEmailPrefix(prefix: String): List } And I would like to have a @Query that retrieves all direct reports for a given user.

Moving to jdk11, gradle multi-project build problem: modules are not supported in -source8 I'm moving some libs to openjdk11 using the third approach described here. The whole project is being compiled into 8, while only module-info.class to 11. In the process of doing this, I found out that writing an empty main somewhere and running it, is the quickest way to check if there are any missing dependencies, the module-info.java has been properly detected and configured (because...