Reliably measure JVM allocations I have two implementations of the same algorithm. I would like to verify that non of them uses more memory than necessary, or, in other words, that they allocate exactly the same number of objects. My current solution is to measure the number of allocated bytes before and after the procedures via threadMXBean.getThreadAllocatedBytes(threadId) and use that as an approximation of the memory footprint. The problem is that this method is unstable, e.i. sometimes it returns a much greater number...

Possible to keep `Unit` as the return type of a Kotlin function when called from Java? I have a kotlin function on a class. fun returnUnit: Unit Java sees the method signature as a function that returns void. Is it possible to instruct the Kotlin compiler to keep Unit as the return type for Java? (not void)

How can I change the color of the positive button on alertdialog? I would like to change the color of the positive button. How can I do this? AlerDialog: fun onSomeClicked(view: View) { val dialog: AlertDialog.Builder = AlertDialog.Builder(view.context) dialog.setTitle("SomeText") .setMessage("SomeMessage") .setPositiveButton(view.context.getString(R.string.ok_dialog)) { p0, p1 -> onCheckPassword(view) } .setNegativeButton(context.getString(R.string.cancel_dialog)) { p0, p1 ->...

Vault state's status to UNCONSUMED/CONSUMED I have taken Bank flow's output as input and updated the value. But I don't know that how to update the vault's state status to "CONSUMED". I thought it will happen automatically based on flowlogic. Bank Node initiated the flow and committed to both Bank and Customer ledger. Customer Node initiated another flow and take Bank's state as input, updated the value and committed on both Customer and Bank ledger as new state. I have done up to this level and below the is sample code....

Get generics class loader for parsing nested Parcelable generic field I have a wrapper of Parcelable generic type but Parcel constructing fails to compile because T class can not be determined generically class MyItem (val model: T) : Parcelable { constructor(parcel: Parcel) : this(parcel.readParcelable(T::class.java.classLoader)) { } } Is there any solution to this case?

Retrofit + RxJava retry with different link The Problem I am using an Api which requires to queries: Title of the Movie Release Year of the Movie But my other Api gives me only the release year for a specific country, so I might have to retry the request with + / - one year. With other words, if the first attemp Fails, I want to retry with a different link/ queries. The Question How can I achieve this using Retrofit and RxJava?

Kotlin setOnclickListener button is not working Hello guys i have a problem on click button fun mainPage(view: View) { val intent = Intent(applicationContext, MainActivity::class.java) intent.putExtra("input", userText.text.toString()) startActivity(intent) } //second button started in here singupButton.setOnClickListener { fun crtUser (view: View) { val intent = Intent(applicationContext,createUser::class.java)...

How to retrieve Google Fit Step data from server? I have recently started playing around with the GoogleFit APIs. I have gone through several stackoverflow posts about this problem but have not seen a good answer yet that works for me. Most answers point to outdated API. The task I want to accomplish is simple: Read the daily step count from the server. Ideally I want the step count retrieved to match what is displayed on https://fit.google.com/ but I have not been able to...

Scope Resolution Operator in Kotlin I have read the following syntax. I have no idea why scope resolution operator is used in it. class XyzFragment : Fragment() { lateinit var adapter: ChatAdapter override fun onViewCreated(view: View?, savedInstanceState: Bundle?) { if (!::adapter.isInitialized) {

Kotlin-Android: Generic Class type usage I am trying to write a generic base activity, that specified its ViewModel type as follows: abstract class BaseActivity : AppCompatActivity() Now I am trying to write a lazy property for my ViewModel initialization: val viewModel by lazy { ViewModelProviders.of(this, getFactory()).get(T) } The error that is displayed is Type Parameter T is not an expression Also using ::class or ::class.java did not help. Can anyone explain the problem? Thank you in advance.

Two SQLiteDao objects are created at the same time, one of which does not create a table when Helper is executed I have two tables, in the open application is going to check. But when I create these two SQLite Dao objects there is always a table can not be created. This table is CashPayDao, even if I changed the implementation of the order to amend and modify the database version number will not be created. When I Commented out WXPayDao will be able to successfully create CashPayDao corresponding table. First, create two SQLite Dao objects in onCreate cashDao = CashPayDao(this) wxDao =...

Android studio3.0 kotlin classNotFoundException I create a new project with kotlin And make a file to execute a main fun, but got a ClassNotFoundException Did much research, but didn't get solution. Hearing from websites, it maybe android studio's bug. I don't know, so ask Exception in thread "main" java.lang.ClassNotFoundException: com.jafir.teststepsensor.TestDelegation at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at...

Kotlin "internal" visibility modifier in Android Suppose you're writing an Android project (not a library). All the files are compiled together so... is there any sense to use an internal visibility modifier in this case?

It seems the compose() not work for me when use rxjava I imitated the project todo-mvi-rxjava to achieve MVI pattern, but I found that the .compose(addOrEditActionProcessorHolder.actionProcessor) method here does not pass, the breakpoint disappears in...

Location is null unless GoogleMap is initialized again What I'm trying to achieve is to display the user's last know location. If the GPS is disabled, request the location setting. When user presses OK, then enables the GPS and moves the map camera to the location found. It works as expected when the GPS is already enabled; however, when it isn't, the map camera just doesn't make a move because the location is null. I can make this work if I add initMap() after the else statement (when location == null) inside the displayLocation() function,...

How to store a data class object in shared preferences using Kotlin? How to store a data class object in shared preferences using Kotlin. I write this code but it not working, it produce crash every time while retrieving data. i have to do for save user booking in local and get every time it from preferences and put that values in singleton. crash isjava.lang.IllegalStateException gson.fromJson(json, BookingResponse::class.java) must not be null. BookingResponse is my Data Class fun saveResponse(context: Context,bookingResponse: BookingResponse) {...

Can't profile Android application in Android Studio I tried to profile my app in Android Studio 3.0.1, but I can't see which methods are using CPU, the list below containing call chart and flame chart is always empty, I am compiling using SDK 26, please check screenshot (some of my classes are in Java and and some in Kotlin) :

Two concurrent string replaces in kotlin string I have a string with wrong directed paranthesis, I want to replace ( with ) and ) with ( at same time, can I do it with a single replace method or I should use a loop? For example I have this string : You need extra time ) or money ( Which should be like this : You need extra time ( or money )

How to disable a button for multiple click? I have a button that when click shows a dialog. But when you click the button quickly in multiple times, it will show 2 or more dialog on the screen depends on how many times you click the button before dialog shows. So I have to close each dialog many times... I already used dialog.isShowing but it seems that it will ignore it when you click the button quickly in multiple times ...So I want to click button at a time when dialog is closed. private var mFlag = false fun...

What is simple way to convert dynamically Kotlin/Js objects to plain javascript object? For example, we have this structure: data class Item( val city: String, val name: String ) val structure = mapOf("items" to listOf( Item("NY", "Bill"), Item("Test", "Test2")) ) And I want to get this object in Javascript: var structure = { "items": [ { "city": "NY", "name": "Bill" }, { "city": "Test", "name": "Test2" } ] } How we could convert map from Kotlin to dynamic type with such...

How to create a simple timer to execute a fun every second using setInterval? I'm new to Kotlin. I'd like to create a simple timer to execute fun every second. I've researched some approaches and found the setInterval. But I can't understand how to implement in the code. All I need...

IllegalStateException in Kotlin context must not be null I am trying to get location but get this error 12-21 163555.369 19072-19072/com.mosquefinder.android.fiveprayers E/AndroidRuntime: FATAL EXCEPTION: main Process: com.mosquefinder.android.fiveprayers, PID: 19072 java.lang.IllegalStateException: context must not be null...

android.view.InflateException: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputEditText android.view.InflateException: Binary XML file line #0: Error inflating class android.support.design.widget.TextInputEditText I am getting this exception lolipop and pre-lolipop android devices but on post lolipop devices it is working fine. My code is:

Firebase - Join chat with password securely How to check if user enters correct password to join a chat. This approach is propably compeletely improper. This piece of code is just to show what I want to accomplish but it isn't working at all. val ref = FirebaseDatabase.getInstance().getReference("chats") ref.child(chatName).child("password").equalTo(password).addListenerForSingleValueEvent( override fun onDataChange(snapshot: DataSnapshot) { Log.d(TAG, snapshot.toString()) // if there is data the password...

LiveData Obserever catch only first value I get list of issues from Firebase Database and return LiveData. fun getAllIssues(): MutableLiveData { val issues: MutableLiveData = MutableLiveData() val issuesReference = FirebaseDatabase.getInstance().reference.child("issues") issuesReference.addValueEventListener(object : ValueEventListener { override fun onCancelled(p0: DatabaseError?) { } override fun onDataChange(snapshot: DataSnapshot?) { if (snapshot == null) {...

Deletion and adding item to RecyclerView not working when using anko So I got two problems. When adding new item, only one item is added and it overwrites the last item from the list (which is added there by hand) but when I keep adding the items I can see "New item added. Number of items: ${adapter.itemCount} " and adapter.itemCount is increasing. When deleting an item I got java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position. The code is very simple. I try changing notifyItemInserted() to notifyDataSetChanged() but nothing has...

Convert java function which uses bytes to Kotlin I have a problem with converting function written in java to Kotlin specific. Here is written in Java: private boolean isOldOemCommissioningFormat(byte[] assetData) { if (assetData == null || assetData.length < mAssetDataDelimeterByteCount + mAssetDataOwnerIdByteCount + mAssetDataIdLeadingZerosByteCount + mAssetDataIdByteCount) return false; int oemMarkerIndex = mAssetDataDelimeterByteCount + mAssetDataIdLeadingZerosByteCount + mAssetDataIdByteCount; if...

How to set package.json configurations using kotlin-frontend-plugin I want the auto-generated package.json to be configured in a way that it points to the outputted webpack bundle file. This is my current gradle configuration: apply plugin: 'kotlin-platform-js' apply from: "$project.rootDir/gradle/deploy.gradle" dependencies { expectedBy project(":") // Compile/implementation dependencies implementation "org.jetbrains.kotlinkotlin stdlib js$kotlin_version" } apply plugin: 'org.jetbrains.kotlin.frontend'...

Firebase Database query users in a loop For example, I have a list of issues. Each issue has owner uid. By this uid, I should find needed users and display his name and photo. I do it with help architecture component ViewModel: issues.forEach { IssueRepository().getIssueOwner(it.owner).observe(this, Observer { }) } getIssueOwner method: fun getIssueOwner(uid: String): MutableLiveData { val user: MutableLiveData = MutableLiveData() val usersReference =...

Is it possible to spread a list inside a list in Kotlin? It is possible to do argument unpacking in Kotlin similar to how it is done in Python? E.g.

>> a = [1,2,3]

>> b = [*a,4,5,6]

>> b

[1, 2, 3, 4, 5, 6] I know that it is possible in Kotlin as follows:

>> listOf(1, 2, 3, *listOf(4,5,6).toTypedArray())

[1, 2, 3, 4, 5, 6] Feels like there is an easier way in Kotlin. Any ideas?