Accessing Edittext views in a Recycleview I have seen a couple of other similar questions, but I still can not seem to achieve my intended goal. In my second activity I have a recycleview in which I would like the user to be able to enter input, how can I gain access to what they type in without ID's to these editText views? class Main2Activity : AppCompatActivity() { companion object { const val GROUP_NAME = "group_name" const val GROUP_SIZE = "" } override fun onCreate(savedInstanceState: Bundle?) {...

Kotlin List interface equals and hashCode methods I just noticed that, in contrast to what is done in Java, the List interface in Kotlin does not define either equals or hashCode methods. This is also true for other interfaces like Set and Map. Was this a design decision? Is there a particular explanation for it? Also, is it safe to say that the following statements will return true, even though there's no explicit contract enforcing them: listOf(1).equals(arrayListOf(1)) listOf(1).hashCode == arrayListOf(1).hashCode

Get all Firestore documents after specific date What I try to accomplish is the following: I have a collection where documents get added with a timestamp in them. I then want to listen to that collection via snapshotlistener, but just for new documents. So I update my timestamp to the newest document-timestamp received, and try to query only the documents newer than my timestamp val path = //...path to my collection @ServerTimestamp private var lastUpdateTime = Any() //my up-to-date timestamp. I first assign it some date in the past, to...

null cannot be cast to non-null type java.util.HashMap in my application fun refreshUsers() { val userData = UserData(this) databaseRef!!.child("User").child(userData.loadPhoneNumber()).child("Finders") .addValueEventListener(object : ValueEventListener { override fun onDataChange(dataSnapshot: DataSnapshot?) { val td = dataSnapshot!!.value as HashMap listOfContact.clear() if (td==null){ listOfContact.add(UserContact("NO_USERS","nothing"))...

Kotlin data class No String-argument constructor with spring data rest I'm using Spring data rest with Kotlin and if I use data classes the associations via uri stops working with the error no String-argument constructor/factory method to deserialize from String value Data class @Entity data class Comment( @Id @GeneratedValue(strategy = GenerationType.IDENTITY) var id: Long = 0, var author: String? = null, var content: String? = null, @ManyToOne var post: Post? = null) { } If I use a simple class instead the association...

Validate Email Address Before Going To Second Activity I have an activity with text edits one for name, email and password and a button that take the user to next activity. The problem is that even if the user entered a invalid email address he still can go to second activity, I want the email address to be checked than if he entered a valid email address he can go to second activity, if not a toast message appears says INVALID EMAIL ADDRESS. I am working with KOTLIN but I can work also with java. Please can anyone guide me on how I can do it...

How can I set setCancelable(false) for anko dialog in Kotlin? I can set setCancelable(false) for a dialog in Code B, now I hope to set the same property for a anko dialog in Code A. How can I do ? Thanks! Code A private fun deleteBackup(){ alert( getString(R.string.DialogDeleteContent), getString(R.string.DialogDeleteTitle)) { yesButton { //... } }.show() } Code B private fun promptBuyWhenExpired() { if (IsExpired(applicationContext) ) { val builder =...

override fun onRequestPermissionsResult on other class I write the Permission class, here have the askMicrophonePermission method. In askMicrophonePermission, I use ActivityCompat.requestPermissions function. But I can't override onRequestPermissionsResult in Permission class. If I want override onRequestPermissionsResult in Permission, not in MainActivity. How to write?? Here is my code. MainActivity: class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) {...

Cannot access activity binding android I have a layout file called activity_suggestions. I am using databinding in it. Hence the file ActivitySuggestionsBinding got generated. The project compiles successfully. But when I try to run the project, I get this error e: error: cannot access ActivitySuggestionsBinding I am using android studio 3.1.2 with kotlin. Any help will be appreciated

Android robolectric unit test load bitmap from drawable I am trying to load a bitmap from a drawable in my resources, but it appears to be empty when the following code is run in unit tests, but not empty when run from a normal activity: val bitmapImage = BitmapFactory.decodeResource(context!!.resources, R.drawable.my_image) val bos = ByteArrayOutputStream() val quality = 10 bitmapImage.compress(Bitmap.CompressFormat.JPEG, quality, bos) val pixels = bos.toByteArray() I really don't understand what's happening, as the same code produces...

How to create object of generic type in a class I have the following class open abstract class NexusAdapter (protected val ctx: Context, private val _layoutId: Int, protected val items: List): BaseAdapter() { override fun getView(position: Int, view: View?, parent: ViewGroup?): View { val itemView = if (view == null) LayoutInflater.from(ctx).inflate(_layoutId, parent, false) else view!! // How do I create the object of type TViewHolder at runtime????...

Include maven dependencies built with Java9 or Java10 in a Kotlin project Is it possible to include Java9 (or 10) dependencies? As Kotlin is only able to compile to Java 8 so far. I'm getting an java.lang.UnsupportedClassVersionError error obviously stating that a class in the JAR/dependency I'm including has been compiled by a more recent version of the Java Runtime. However am I not able to specify a newer JDK, which is able to run classes compiled with older versions (the Kotlin stuff?). org.apache.maven.plugins maven-compiler-plugin 3.7.0 9...

Check If Condition in for loop in kotlin I want to change the btn.text when value is 5, but it's not working. Here's my code: fun loopFunction(){ for (i in 1 until 5 step 2) { if (i == 5){ btn.text = "Timer End" //btn is Button } println(i) } }

Adding custom class fields in Kotlin at compile time Kotlin Android Extensions basically dynamically adds fields to a class by parsing the View xml layout file. Is there a general exposed mechanism in Kotlin for doing so with any parsable data? For example: generating fields from a custom json file, REST service, or parsing html, or xml in general?

How to call extension functions from generic code Given the following classes and extension functions class Foo class Bar fun Foo.run() = "run" fun Bar.run() = "run" fun main(args: Array) { val x = listOf(Foo(), Bar()) val y = x.map({a -> a.run()}) //compiler error println("Hello, world!") } is it possible to call run in a generic way? Somehow this is an attempt to emulate Swift's protocols and extensions when extending a class via an interface or is either not possible or undesireable.

commit() fragment transaction after activity.onSaveInstanceState() has been called In my application I have an Activity that holds 3 Fragments. The very first time the Activity is created, Fragment 1 is displayed. Next, all fragment transactions will be executed after a network operation. For example: Fragment 1 has a button to make a request to the server and when the result is ready, Fragment 1 uses a listener to call a method defined inside the parent activity, to replace fragment 1 with fragment 2. This works fine, except when the parent activity receives the callback...

How can I implement coroutines for a parallel task So, I have this piece of code: for (z in 0 until texture.extent.z) { println(z) for (y in 0 until texture.extent.y) for (x in 0 until texture.extent.x) { val v = Vec3(x, y, z) / texture.extent var n = when {...

Set Spannablestring Bad Performance I have Performance problem when set my SpannaleString to TextView - Progress Bar freezing on 30-40s, after then all data is showing . I sugges problem in drawing SpannableString in Text View. Can you help? Helper with problem: class ReplaceButtons { fun replaceSymbolsPS(text: String, context: Context): Single { return Single.create { val options = BitmapFactory.Options() var myIndex = 1 var myIndex1 = 1 var myIndex2 = 1 var myIndex3 = 1 var...

BroadcastReceiver for monitoring phone call state not works properly for Android O API 27 I have a broadcast receiver class which identifies phone call states, (outgoing, incoming, CALL_STATE_OFFHOOK, CALL_STATE_IDLE ) it works fine for android N and for lower versions, but for Android O, receiver can't identify if call has been end, there is no CALL_STATE_IDLE state, but identifies outgoing, incoming and CALL_STATE_OFFHOOK states correctly private fun startListening(context: Context) { val telManager = context.getSystemService(Context.TELEPHONY_SERVICE) as? TelephonyManager...

why android studio required to Add non null Asserted(!!) call even after safety is added in Kotline "it" denote List of Object in the Image. here checking list is not empty. but showing an error to add (?)safety . but again show an error to add non null Asserted(!!) even add safety.error can fix only after add this. if (it?.isNotEmpty()!!) { //do your work here } why android studio required to Add non null Asserted(!!) call .

Math: Determining circle points from a lat and long, incorrect results? I need to get 4 coordinates (sw ne nw se) to create a circle from a latitude, a longitude and a distance. This is the code I'm using, partically retireved from this SO post (although C# converted to Kotlin): Create circle coordinates given central lat/long and radius private val EARTH_RADIUS_NM = 3437.670013352 private fun plot(latt: Double, long: Double, radius:...

Kotlin: withContext() vs Async-await I have been kotlin docs and If I understood correctly the two kotlin functions work as follows:- withContext(context): switches the context of the current coroutine, when the given block executes, the coroutine switches back to previous context. async(context): Starts a new coroutine in the given context and if we call await() on the returned Deferred task, it will suspends...

Firestore query a lot of documents I have a firestore database with a lot of data in it. In my application I have to get a lot of documents from it at once. I know the exact keys of them. It is maximum 500-600 documents at a time, and an average of 300 of them, with only 3 fields in each. Is the best way to get them one-by-one in a new thread and request for each? This needs a lot of parallel connections.. This is what I do now, but it is a bit slow (several secs), I am looking for a better solution now. I have no...

Unable to launch Activity from Fragment Adapter due to writeToParcel Null Object Reference This is a very confusing problem for me. I have a SearchFragment that uses a SearchAdapter. The SearchFragment accepts a ParceleableArrayList and displays the contents to a recyclerview. Everything works fine until you click on any item on the Recyclerview. Supposedly, once you click an item, a separate activity is launched. Only one variable is put in the intent, which is the id and it is not null. I do this and for about a second, I see the activity is launched (because the layout is...

Why is "object" underlined in red in my Firebase code? Trying to get into Kotlin using Firebase. The examples I have viewed want me to add the following code: object: ChildEventListner. In Java this was new ChildEventListner. But the object part is marked red with the message: object is not abstract and does not implement abstract member. Not sure what it means or how to solve it. Here's the db = FirebaseDatabase.getInstance().reference db!!.child("cookies").addChildEventListener(object: ChildEventListener { //CODE HERE TO GET DATA...

Inherit parent properties from a Base class with Jpa annotations in Kotlin All our JPA Entities have an @Id, @UpdateTimestamp, Optimistic Locking etc... My idea is to create some kind of Base class witch contains everything that every JPA Entity needs to have which can be inherited by all of them. open class JpaEntity ( @Id @GeneratedValue(strategy = GenerationType.IDENTITY) var id : Long? = null, @UpdateTimestamp var lastUpdate : LocalDateTime? = null ... ) I trying to find how I can use this class (or any other solutions) so that the devs...

How do i use non static method in kotlin? I have one class that extends with broadcast receiver. So when a message is arrived that method call. Now in that method i am calling another class's method to set the text in edittext. But since i am using kotlin i need to use a static method in companion object . So i how do i setText in my editText in that method or somewhere else. My BroadCast Receiver Class : class SMS : BroadcastReceiver() { val OTP_REGEX = "[0-9]{1,6}" override fun onReceive(context: Context, intent: Intent) {...

Getting random crash when call receiver pick up the call using Pjsip(Crash is getting inside pjsip)

best way of making online apps? i wanted to know how this online apps and games are created? how do they handle the request do they use normal libraries like volley and retorfit or they use socket programming or other ways? how do they handle real time tasks?

How can my Kotlin API classes be constructed from json? (using Moshi) I am refactoring and adding to the API communication of an app. I'd like to get to this usage for my "json data objects". Instantiate with either the properties directly or from a json string. userFromParams = User("user@example.com", "otherproperty") userFromString = User.fromJson(someJsonString)!! // userIWantFromString = User(someJsonString) Getting userFromParams to serialize to JSON was not a problem. Just adding a toJson() function takes care of that. data class User(email: String,...