How to make field required in kotlin DSL builders In Kotlin, when creating a custom DSL, what is the best way to force filling required fields inside the builder's extension functions. E.g.: person { name = "John Doe" // this field needs to be set always, or compile error age = 25 } One way to force it is to set value in a function parameter instead of the body of the extension function. person(name = "John Doe") { age = 25 } but that makes it a bit more unreadable if there are more required fields. Is there any other way?

Convert Object to a List using Gson Here's my Response { "entity": "methods", "card": true, "debit_card": true, "credit_card": true, "amex": true, "netbanking": { "AIRP": "Airtel Payments Bank", "ALLA": "Allahabad Bank", "ANDB": "Andhra Bank", "UTIB": "Axis Bank", "BBKM": "Bank of Bahrein and Kuwait", "BARB_R": "Bank of Baroda - Retail Banking", "BKID": "Bank of India", "MAHB": "Bank of Maharashtra", "CNRB": "Canara Bank", "CSBK": "Catholic Syrian Bank", "CBIN": "Central Bank of India", "CIUB": "City Union Bank", "CORP":...

Retrofit 2 and Spring Boot Authorization doesnt work I want to auth with JWT Spring security. Retrofit instance Retrofit.Builder() .baseUrl(MOCK_URL) .client(client) .addConverterFactory(GsonConverterFactory.create(gson)) .addCallAdapterFactory(RxJava2CallAdapterFactory.create()) .build() Api @FormUrlEncoded @Headers( "Authorization: Basic VGVzdENsaWVudElkOlRlc3RDbGllbnRTZWNyZXQ=", "Content-Type: application/x-www-form-urlencoded" ) @POST("oauth/token/") fun...

How to deserialize json string of 3-level typed object in Kotlin? I am using Gson library to serialize/deserialize objects, but when I try to deserialize object like this List I've got List although IDEA confidently says it's DatTime and not LinkedTreeMap.

How to pump streams with offset and length in vert.x? I'm porting a kotlin rest server to Vert.x, but I have some trouble finding an alternative to InputStream.skip(), OutputStream.write(buffer, 0, len) and how to append to a file on disk. Is it possible using the Pump.pump()? Do I have to override the ReadStream and WriteStream? My old code is: val fromOffset = FROM_OFFSET.getLongParam(req, false, 0) val toOffset = TO_OFFSET.getLongParam(req, false, -1) val component = repository.getComponent(contRep, docId, compId)...

Create 'fake' property that just sets property of a property Sorry for the wonky title, I have no idea how to properly word this. I've got the following situation: I have a class that has a Paint object for drawing something. I want the class to have the appearance of having a color field. Setting that field should just set the color of the stored Paint-Object and not actually set a field. In Java I would do it like this: public class Foo { private Paint p; public void setColor(int color) { p.setColor(color); } public int...

How to declare a Kotlin function with return type 'void' for a java caller? I have a library that is completely written in Kotlin including its public API. Now a user of the library uses Java, the problem here is that Kotlin functions with return type Unit are not compiled to return type void. The effect is that the Java side has always to return Unit.INSTANCE for methods that are effectivly void. Can this be avoided somehow? Example: Kotlin interface interface Foo{ fun bar() } Java implementation class FooImpl implements Foo{ // should be public void...

Is there a de facto registry for discovering Java libraries? I grew out of touch with the Java community as I embraced Javascript and node.js for web development. I found myself blown away by the NPM package registry for Javascript tools and libraries. If it's been done, chances are I can find it and even choose from multiple competing implementations. And then in one fell swoop I can npm install it to make it available to my project. I'm now getting back into Java and haven't found anything analogous. My searches for Java libraries have led me all...

How to declare a Kotlin Lambda with return type 'void' for a java caller? I have a library that is completely written in Kotlin including its public API. Now a user of the library uses Java, the problem here is that Kotlin Lambdas with return type Unit are not compiled to return type void. The effect is that the Java side has always to return Unit.INSTANCE for methods that are effectivly void. Can this be avoided somehow? Example: Kotlin Lambda interface Foo{ fun bar(x:(String)->Unit) } Java call public void call(){ foo.bar(this::processString) } //the...

Deploying Kotlin Spring Boot Application Via WebSphere I've written a Spring Boot microservice in Kotlin using IntelliJ Idea where it runs fine locally. I need to deploy it via WebShpere but am having problems launching the WAR there. The main class of the microservice is as follows import org.springframework.boot.autoconfigure.SpringBootApplication import org.springframework.boot.runApplication @SpringBootApplication class MyApplication fun main(args: Array) { runApplication(*args) } After creating the WAR using mvn clean install, if I...

Intersection of two paths or a path and a point never returns true I came across this and this this questions, all about detection intersections in Android. Well, I couldn't manage to make them work with the final code, so I made an example where 2 lines definitely intersect. Not even lucky in that case. I've made an example code with two straight paths, regions...

What is the difference between closureOf and delegateClosureOf in Gradle Kotlin DSL The official doc says: You may sometimes have to call Groovy methods that take Closure arguments from Kotlin code. For example, some third-party plugins written in Groovy expect closure arguments. In order to provide a way to construct closures while preserving Kotlin’s strong typing, two helper methods exist: closureOf {} delegateClosureOf {} Both methods are useful in...

Integrate Kotlin Class inside Bottom Navigation Acitivity I have created a kotlin bottom navigation activity and then I try to display the kotlin subject class once I click the bottom navigation button. I am not sure how to add subject.kt class once I click the bottom subject bottom. Please share your thoughts. Student.kt class StudentNames : AppCompatActivity(){ private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item -> when (item.itemId) { R.id.navigation_home -> {...

Kotlin Reflection My purpose is create json parser function which uses JSONObject and JSONArray (package:org.json). In the parser function I want to pass json string and json model as parameter to function and it will return that reference classes with filled by json fields via reflection (I know lots of json library available but I don't want to do use them) JsonParser sample code class JsonParser { fun parse(json: String, clazz: KClass): T? { if (json.startsWith("{")) { val...

Android DataBinding item position in a recyclerView I have a Fragment with a ViewModel (so Mvvm) and in the xml I have 2 RecyclerView with both having their own Adapter using the same itemList because I want to see the same data in 2 different layout. Before switching to Mvvm, I could reference the adapter and the recyclerView and could reach "getChildAdapterPosition" But right now this is quite impossible it seem. I made some custom BindingAdapter to bind my Adapter, a CustomPageSnaperHelper and a scrollListener. but now I can't seem to be...

transform list with rx-java, run operation on mid-result list I have: List fun1: T -> U fun2: U -> void funList: List -> void I want to apply concurrently(with rxjava2) on each element function fun1, and then fun2 on result of the former. fun2 returns void, so I want to get just Completable that completes when all elements are transformed by these two functions. One complication, that is above my rx-java skills: if all results of fun1 are computed I want to run funList on whole list of elements U (List). Execution of funList should be concurrent...

Test service from with dependencies in spock I am working with a kotlin and spring project, Now I am trying to do the test of some service, which has some dependencies, I am having some problems, in order to get a success test. Maybe I my design is not good enough, moreover I have problems trying to call the method from the spy object, I am getting the issue: Cannot invoke real method 'getClubhouseFor' on interface based mock object. This is my code, Could you give me any idea about what I am doing bad. Thanks in advance!!!! This is my...

Setting different JVM targets in an Android Kotlin project for the app and unit tests Based on the documentation I've set my Android project's Gradle build file to use the 1.6 JVM target for Kotlin compilation: tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all { kotlinOptions { jvmTarget = "1.6" } } But now I want to target JVM 1.8 just for my unit tests. How do I modify this so that compiling the app uses 1.6 but unit tests use...

Change the json property name depending on the @JsonView in Kotlin I am trying to use Jackson serialize same DTO object in 2 different ways, depending on the @JsonView. I want to use 2 different names for the same field. In one case I want to name the json property myField (just like the class field name), in the other I want it to be named myInternalApiField. As a result I would like to see outcomes similar to the presented below: Usage 1 (External API View): { "myField": "value1", "myOtherField": "otherValue" } Usage 2 (Internal API View):...

picasso save image progress onDestroy I load image with Picasso, but this image may be very large, I want't reload again from begin, is it good idea to call Picasso from Server? Or I should write pauseTag ?

How do I convert a byte array with null terminating character to a String in Kotlin? When I attempt to retrieve a value from the device via Bluetooth, it comes out in ASCII, as a null terminated big-endian value. The device software is written in C. I want to retrieve the decimal value, i.e. 0 instead of 48, 1 instead of 49, 9 instead of 57, etc. @Throws(IOException::class) fun receiveData(socket: BluetoothSocket?): Int { val buffer = ByteArray(4) val input = ByteArrayInputStream(buffer) val inputStream = socket!!.inputStream...

versionCodeOverride equivalent for Gradle Kotlin DSL android.applicationVariants.all { variant -> variant.outputs.each { output -> int newVersionCode = android.defaultConfig.versionCode * 10 + abiVersionCodes.get(output.getFilter(com.android.build.OutputFile.ABI), 0) output.versionCodeOverride = newVersionCode } } I am trying to convert this Gradle Groovy DSL code to the new Gradle Kotlin DSL. I want the code to work exactly like it used to were APK splitted variant follows my versionCode pattern...

Implementing OpenWeatherMap search engine into Android app I'm trying to create an app using OpenWeatherMap API. The problem I face is with search function. I want to implement AutoCompleteTextView, but here I face following problems: I need to download JSON array containing all cities. File containing this all is 4mb, but it is packed in gzip archive. I can unpack it and download with the code provided below. After unpacking output file is 28mb. val listUrl = URL("http://bulk.openweathermap.org/sample/city.list.json.gz") try {...

Kotlin : Inheritance and issue with parcelable data I am trying to get my head around an issue and i couldn't find any particular solution. Base Class open class FeedBase() : Parcelable{ var type : String ="" constructor(parcel: Parcel) : this() { type=parcel.readString() } override fun writeToParcel(parcel: Parcel, flags: Int) { parcel.writeString(type) } override fun describeContents(): Int { return 0 } companion object CREATOR : Parcelable.Creator { override fun createFromParcel(parcel: Parcel): FeedBase {...

android kotlin - app do not show me toast i want when someone insert more than 3 number in month input, the Toast should show a error message, i try it and the app do nothing ! why ?(i am beginner) another question how can i use try and catch with that ? @SuppressLint("SetTextI18n") fun onClickButton(view: View){ getAGE.setOnClickListener { val Get_year_input = age_year_input.text.toString().toInt() val getCurrentYear = Calendar.getInstance().get(Calendar.YEAR) val finish_year_input...

How to find out the latest version of Kotlin in Android Studio I have opened an Android Studio project which was created some time ago and the IDE says that a gradle plugin for Kotlin supports a Kotlin version 1.2.51 or higher. I would like to set it to the latest version but I have to go to the Kotlin website on which it's not easy to find out this information. Is it possible to find out the latest version of Kotlin in Android Studio?

How to click a button in a fragment to switch othe Tab in Kotlin? The following code is based by Android Studio Wizard 3.2.1 for creating Tabbed Activity. There is a button1 on PlaceholderFragment1 connected Tab1, and a button2 on PlaceholderFragment2 connected Tab2 I hope to click button1 to switch to Tab2, and click button2 to switch to Tab1, How can I do ? BTW, I have read How to change tab on button click in Android? and <a...

&lt;Kotlin&gt; Can I use Spinner when choosing date or time? I would like to use Spinner when the user closes date or time, not calendar visualization type. Since I use DatePickerFragment as a DatePicker, I can't change XML(or I just don't know how.). I know that there is a solution in Java. But I couldn't convert the file I found into Kotlin.

JSONException: Value in kotlin I want to fetch json data in my app . l used recycle view for displaying data . when l run app l got FATAL EXCEPTION E/AndroidRuntime: FATAL EXCEPTION: main Process: com.iraqairoirt.iraqairports, PID: 29757 java.lang.RuntimeException: java.lang.reflect.InvocationTargetException at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1386) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Method.invoke(Native Method) at...

Build Uber Application on Cordova/PhoneGap? I want to build Uber like taxi solution on Android. I'm something good at Cordova. Can I build my app with Cordova/PhoneGap like tools? Or I need to build Native Build with Java/Kotlin? Which is better and worth for long term maintenance?