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for the first attempt (marked gray):

Elvis operator always returns the left operand of non-nullable String

for the 2nd attempt (marked yellow):

condition currentUser?.office?.name.toString() is always 'true'

Why is that not possible to be null?

I mean, I want use a default placeholder if either the passed string “currentUser?.firstName” or “currentUser?.lastName” to

getString()

is null. Can I use this with elvis? I couldn’t find a way (unless using if/else,etc, just exploring something more clean)

Hi, I would like to profile my application, but on Release variant. Is there a tool or a way to do it?

Hi there! It seems like there is little to none information about the fact that android recreates the activity when an exception is thrown inside a ViewModel class (instead of just crashing the app). Upon doing so, some of my app resources are left in an inconsistent state. I would rather let it crash instead. Can anyone help me with some information in this regard?

My buiild.gradle is failing. I get the Error:

Cause: only whitespace content allowed before start tag and not \u0 (position: START_DOCUMENT seen \u0... @1:1)

while using `apply plugin: "androidx.navigation.safeargs"`` i

I am trying to control AnimatedVectorDrawable based on my network requests. I searched multiple articles but I can start the animation using Animate class, but cannot find to pin point how to handle animated vector drawables based on custom duration or trigger particular target, for example below loading class

Hi is there any way we can hold the old position of the item in recycler view I want to show something if the new item click and if the same item click nothing should happen

So to save the item id --> holder.getItemId() ??

Is it possible to create a generic function which limits the type

T

to 2 different objects? For example, here we limit to type

Cat

or

Dog

something like(this is pseudocode):

private fun<T : Cat or Dog> convertToIntArray(objects: List<T>) : IntArray {
    val objectIds = arrayListOf<Int>()
    objects.forEach {
        objectIds.add(it.id)
    }
    return objectIds.toIntArray()
}

// Then pass something like this:
val cats = convertToIntArray(oldListOfCats)
val dogs = convertToIntArray(oldListOfDogs)

Is there a method that runs on a collection of objects, returning a collection that contains a specific field from the original collection? ( I tried searching through all collection methods with no success, no google help too) For example:

data class Dog(val id: Int, val name: String)

val dogs = arrayListOf(Dog(0, "jack"), Dog(1,"Jacky"), Dog(2, "Chan"))
val listOfDogsId = dogs.somecoolmethodhere(it.id) // listOfDogsId = arrayListOf<Int>(0,1,2)

When using the new viewbinding, how can I create a ViewBinding for the root view similar to how databinding does it below?

val viewDataBinding: T = DataBindingUtil.bind(itemView)

Can anyone please shed light into this? Seems Java interop issues

class Foo<T> {
    fun <T> foo(a: T, b: T) = a == b // compiles
}

class MyCallback<T> : DiffUtil.ItemCallback<T>() {
    override fun areItemsTheSame(oldItem: T, newItem: T): Boolean =
        throw Error("TODO")

    override fun areContentsTheSame(oldItem: T, newItem: T): Boolean =
        oldItem == newItem // Doesn't compile - "equals in not implemented on T"
}

Hey guys, Is it possible to tell retrofit to ignore certain fields of an object when sending the object over the network? We have a request object

Profession

that we send to our backend using Retrofit.

data class Profession (
	@SerializedName("activeSince") var activeSince : Long?,
	@SerializedName("name") var businessName : String?,
	@SerializedName("description") var businessDescription : String?,
	@SerializedName("licenseImageUrl") var licenseImageUrl : String?
)

Sometimes we send the entire object, but other times, I prefer to only send specific fields (for example, only the

businessDescription

and

businessName

). Is it possible to tell retrofit to not include the other 2 fields in the network request? (

activeSince

and

licenseImageUrl

). Note: I can’t send

activeSince

and

licenseImageUrl

as null. Our backend will send me back errors if I attempt to do that (edited)

Hey guys, I have a list

returnedExpertiseFields

inside a ViewModel. I want to initialize this list using a query to Room.

returnedExpertiseFields

gets returned before it is initialized with values from Room, as in the code below:

fun getExpertiseFieldsById(expertiseFieldsIds: IntArray) : List<ExpertiseField>{
    var returnedExpertiseFields = listOf<ExpertiseField>()

    viewModelScope.launch {
        returnedExpertiseFields = mExpertiseFieldFieldsRepository.getExpertiseFieldsFromDatabaseById(expertiseFieldsIds)
    }

    return returnedExpertiseFields
}

returnedExpertiseFields

will return an empty list of

ExpertiseField

. What can I do to make sure I always wait to Room query to be returned? I thought calling launch is synchronous? (If you need my repository code I will post it, I just thought it might not be necessary) Also, If any of you have any tips for debugging when using coroutines I will be glad to hear. I initially tought my Room query is broken. After long debugging I realized I am jumping between breakpoints rather them skipping them.

Just publishedaeroplanenew @kotlin library - #LiveStream-kt. It's a class which can observe💡 changes of data in real-time⚡and emit values too from any module in your appmobile phone. Don't forget to give 🌟 on GitHub if you like it.😉 Link: https://github.com/PatilShreyas/LiveStream-kt

Hello everyone! Does

@Parcelize

works on Pair type as well? Or in the other hand, does it work on classes that implement

Serializable

. ? I tried on a sample app and it worked. But I have a crash in Crashlytics:

Fatal Exception: java.lang.RuntimeException

Parcelable encountered IOException writing serializable object (name = kotlin.Pair)

keyboard_arrow_up

Is there a common way that apps receiving an ACTION_SEND intent let the launching app know if the action was completed (eg user launches share sheet in App A -> taps whatsapp -> whatsapp populates message draft with link -> user taps send -> intent is returned with some special field denoting that a share send was completed)? edit: I've combed through the docs and can see how we can confirm that another app was launched from the share sheet; just haven't seen a way for us to confirm that that apps actually completed the intended action

I’ve a pretty weird question/requirement! I’m building an android SDK/library. In the library I want to know whether app is either • running on simulator • physical device • whether it’s in beta testing on google play • or it’s product build Based on my knowledge, I can only detect

simulator

vs

physical

based on some checks on

Build

class values But there is no way for SDK to know about

beta testing

vs

production

unless the developer of the app using the SDK provides that information via a

public API

Could someone confirm this ? OR if there is a way to do this then provide some insights.

Reason is to route API calls and data to a particular endpoint so various data doesn’t end up skewing production data.

I can do that via different API Keys for all for cases, but that’s off the limits right now.

I have a recycler view and I want to navigate to item details on click how do I do it? I mean this works just fine (from inside of adapter)

holder.rootView.setOnClickListener {
            it.findNavController().navigate(R.id.numberDetailsScreen, bundleOf("numberName" to item.name))
        }

the thing is that (from what I know) convention tells you to create Navigator interface but doing so would require passing the event up somehow so I could call this

interface NumbersListNavigator {
    fun openNumberDetailsActivity(numberName: String)
}

Hello everyone. I am developing an online quiz application. Do you think Firebase is suitable for real-time multiplayer? The game I want to do will be like a quiz up application. Is there a platform you recommend if Firebase is not suitable? i didnt find any example. I'm a little nervous about latency. I couldn't decide between websocket or firebase. what is your suggestion?

I'm doing an interview homework that's an android app, the only thing that's left to do is network error handling I have no idea how to approach this, could you help?

Hey everyone, when using Kotlin Synthetics how do you name the view IDs? Do you stick with the traditional snake_case or do you go with camelCase? I’ve went with camelCase because it gives a consistent code style within the Kotlin files. Interested in what others do.

Wrote an article on token based authentication using retrofit (& Kotlin): https://medium.com/@tirgei/token-authorization-with-retrofit-android-oauth-2-0-747995c79720

Hi all, I made a code that returns a

User

object from the Shared Preferences. Here is the line of code I use:

private val mCurrentUser = Defaults[PrefsKeys.user]!!

So

Defaults[PrefsKeys.user]!!

returns the current

User

object stored in Shared Preference. The issue is when I change the value in the Shared Preference,

mCurrentUser

is still the same

User

object. Can I replace

mCurrentUser

to be an actual call to the SharedPreference? I guess I am trying to make something like an alias. Because calling Defaults[PrefKeys.user]!! everytime is not very readable.

I have a cart which stores data in Room Database. How is it possible for me to automatically update my Grand Total when an item Sub Total is changed within the Cart? I’m using the following SQLite functions:

@Query("SELECT * FROM cart_table")
fun getAllItemsFromCart(): LiveData<List<Cart>>

@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insert(cart: Cart)

@Query("DELETE FROM cart_table")
suspend fun deleteAllItemsFromCart()

@Delete
suspend fun deleteItemFromCart(cart: Cart)

@Query("SELECT COUNT(*) FROM cart_table")
suspend fun itemCount(): Int

@Query("SELECT SUM(total) FROM cart_table")
fun getGrandTotal(): LiveData<Double>

@Query("UPDATE cart_table SET quantity = quantity + 1 WHERE id = :id")
suspend fun increaseQuantity(id: Int)

@Query("UPDATE cart_table SET quantity = quantity - 1 WHERE id = :id")
suspend fun decreaseQuantity(id: Int)

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Hi guys, I have 2 Activities, and 1 fragment inside one of them. `MainActivity`: Contains a Fragment

UserFragment

, the fragment display data of a User, the data is fetched from the SharedPreferences.

EditUserActivity

:Edits the data of the user, and once editing is done, this activity calls

finish()

and we go back to

MainActivity

, which displays

UserFragment

When returning to

UserFragment

, the data displayed is the old data for the user (the unedited data) I can think of 2 ways to make the fragment display fresh data, can anyone think of a smarter way, or explain which way below is better in terms of design? 1. Make

UserFragment

start

EditUserActivity

with

startActivityForResult

, and return a success or failure code, if success we do some data refresh. 2. Make

UserFragment

terminate itself once we navigate to

EditUserActivity

, and make

EditUserActivity

launch

MainActivity

with

UserFragment

on a backpress or successful save. Even if there is a way that is tricky and should not be in production i would like to know as I want to expand my skills please, thank you! 🙂

My Android emulator has no internet on a macOS that has internet. I have no idea how to investigate or what do do? Any idea? cause this is making me mad 🙂 Edit: after using Google DNS and wiping out the data and updating everything, the internet started to work again but I don't know why

Any idea why I can’t return a String to my

uploadFileToFirebase

function? What am I doing wrong? (part in red says):

return is not allowed here