kotlinlang #android

// Replace contents of a view invoked by the layout manager
    (no override) fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        holder as ImageViewHolder
        holder.bindView(position)
    }

kikebodi

05/10/2018, 3:40 PM

Hi all! I'm developing an app for runners with a heart rate monitor integration. Currently supports only Polar, but I need to support several more devices (Garmin, Suunto, etc ...). Do you know any library to handle this? All suggestions are welcome 🙂

:google: 2

:stackoverflow: 3

Lukas Anda

05/11/2018, 10:34 AM

Hi guys, anyone tried the new Canary build of Android studio with Navigation Editor ? It does not want to run with GitHubViewer sample from Google. I mean it compiles without errors but I can not visually see what there should be with fragment navigation, only "Waiting for build to finish" although I tried to build the project like 20 times

:stackoverflow: 3

rCorbellini

05/11/2018, 1:48 PM

Does anyone know if Coroutines plans at some point don't be a library? and become part of kotlin's core

kenkyee

05/11/2018, 10:32 PM

When you target P or anything not a released version, it's always been painful. Don't do it unless you have to

➕ 2

arekolek

05/12/2018, 7:59 PM

Where would one submit an issue against the Data Binding library, about interop with Kotlin? There's a new method

android.databinding.ViewDataBinding#setLifecycleOwner

that doesn't have a corresponding getter, which means that we can't use property access syntax, unless https://youtrack.jetbrains.com/issue/KT-6519 is resolved.

samp

05/12/2018, 8:36 PM

Does anyone know how to test android application on virtual brand specific device? I want to test something on Huawei phones and I don’t have any real Huawei device/phone.

:stackoverflow: 4

yuvraj24

05/13/2018, 5:40 AM

Check out my new Kotlin library which offers a great alternative to native Snack bar & Toast in Android. https://medium.com/@yuvrajpandey24/bored-of-snackbar-toast-livesmashbar-to-the-rescue-b124034033fc

Filip Husnjak

05/13/2018, 10:01 AM

Hey guys! I am currently converting some java code to kotlin for my app and i have a question regarding Callbacks vs Closures. My java code uses a callback: Ex:

public interface Callback {
   void onSuccess(Class item);
   void onError(Error error);
}

I was thinking of replacing this callback with a closure instead and my question is if it is better to add two closure parameters or to just have one? Is there a best practice for this? Ex:

onSuccess: (item: Class) -> Unit, onError: (error: Error) -> Unit
OR
callback: (item: Class, error: Error) -> Unit

/Thanks

kioba

05/14/2018, 9:47 AM

How do you solve the issue with the

@Nullable

annotation on the

getActivity()

and

getContext()

in the android SDK 27 changes ? Personally I’m not keen to spread the nullable context all around the app.

w_bianrytree

05/14/2018, 10:23 AM

Hi there. not kotlin related but android question. I have a flavor for prod/preprod but i can't use

preprodDebugImplementation

. Anyone knows why?

Error:(96, 0) Could not find method preprodDebugImplementation() for arguments [] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

Thanks!

:stackoverflow: 7

sindrenm

05/14/2018, 11:34 AM

What do you guys think about the added visibility setters and getters on

View

in android-ktx? I find the getters really handy and readable, but the setters feel “imbalanced” and not thought through:

inline var View.isVisible: Boolean
    get() = visibility == View.VISIBLE
    set(value) {
        visibility = if (value) View.VISIBLE else View.GONE
    }

inline var View.isInvisible: Boolean
    get() = visibility == View.INVISIBLE
    set(value) {
        visibility = if (value) View.INVISIBLE else View.VISIBLE
    }

inline var View.isGone: Boolean
    get() = visibility == View.GONE
    set(value) {
        visibility = if (value) View.GONE else View.VISIBLE
    }

In my opinion, saying

button.isVisible = false

in Android doesn't really make sense because of the difference between

View.INVISIBLE

and

View.GONE

. What do you guys think?

👍 1

Znkenza

05/14/2018, 11:48 AM

hello everyone, I am a beginner under android and I am very happy to be among you

👋 20

👍 1

rkeazor

05/15/2018, 2:21 AM

Instead of opening a existing project try opening a new project and see if the issue persist. If it doesnt than it probably means you might have to upgrade some of your plugins.also keep in mind it's still in alpha,so there will always be bugs

Darshan Mistry

05/15/2018, 5:17 AM

Hello can you suggest me kotlin open source project like kotlinconf-app(https://github.com/JetBrains/kotlinconf-app).

:google: 2

:stackoverflow: 3

oleksiyp

05/15/2018, 9:21 PM

MockK now supports Android instrumentation tests http://mockk.io/ANDROID 🎉🎉🎉🎉🎉

👏 1

🎉 5

damian

05/15/2018, 9:21 PM

My Android Studio has been having lots of trouble resolving

kotlinx.android

synthetic extensions lately... I would say that they're just unresolved 80% of the time, which makes editing very difficult. I keep looking at the bug tracker but haven't seen any issues... is this a known or common problem? Has it been fixed in a recent update to something that I'm not aware of? Currently on AS 3.1.2 w/ Kotlin plugin

1.2.41-release-Studio3.1-1

of the plugin 😕

sudhanshu singh

05/16/2018, 8:24 AM

I have a singleton Class

class UserManager private constructor() {
	private object Holder {
		val INSTANCE = UserManager()
	}

	var currentUser: UserModel? = null
		private set

	companion object {
		val instance: UserManager by lazy { Holder.
and I want to use this in xml for databinding, but the following gives 
android:text="UserManager.Companion.getInstance().getCurrentUser()}

error: Could not find accessor for UserManager.Companion.

paras

05/16/2018, 9:17 AM

Hey guys, anyone here have worked on custom canvas drawing before… I need help.

:stackoverflow: 5

adams2

05/16/2018, 4:24 PM

where can I read more about the status of KAE view caching

sudhanshu singh

05/17/2018, 11:05 AM

is there any difference in these two

val isEmpty: Boolean
    get() = this.size == 0

val isEmpty =  this.size==0

nickk

05/18/2018, 9:37 AM

I replaced

compile

with

implementation

in my Gradle build files and now I am getting this cryptic error: Internal compiler error. See log for more details

Caused by: java.lang.AssertionError: annotation tree hasn't been attributed yet: @kotlin.Metadata(mv = {1, 1, 10}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0018\u0002\n\u0002\b\u0002\n\u0002\u0010\u0002\n\u0000\u0018\u00002\u00020\u0001B\u0005\u00a2\u0006\u0002\u0010\u0002J\b\u0010\u0003\u001a\u00020\u0004H\u0016\u00a8\u0006\u0005"}, d2 = {"Lgr/test/fieldobservations/ui/LocationPickerExt;", "Lgr/test/ui/LocationPicker;", "()V", "createAnnotations", "", "app_debug"})

Any idea? (using AS 3.1, Kotlin 1.2.41) This seems to be related to kapt.

ghedeon

05/18/2018, 2:44 PM

Hi, would like to validate an approach. Some time ago I asked here about kotlinx synthetic and long view ids. To give you an idea, I happened to work on a project with this frankenstein:

https://i.imgur.com/QzedJhB.png▾

Possible solutions: 1) don't bother with synthetic 2) get rid of id prefixes, have ids with same names in different layouts and let the android to figure out the context As a proof of concept I decided to workaround with kotlin imports aliases, so I can rename my variables regardless of the actual xml id and here is a small demo of the plugin that helps to automate the process.

https://i.imgur.com/Bdg931e.gif▾

It's pretty much self-explanatory, the

Generate Synthetic

action is added, that imports ids from layout file with alias that can be edited to your taste. Also, it can be configured to convert underscore to camelCase. Now, the real question is, would it benefit anyone or I'm solving nonexistent problem?)

Ronald Daugherty

05/18/2018, 3:06 PM

I'm getting a response from a server with information when a task was done. The data has to be converted to a float to so it can be displayed in a chart. I would like to filter the data display but a 7 day , 30 day, and year results. Can someone point me in the right direction to how I would do sort this info? Thanks

:stackoverflow: 3

Darius Morar

05/18/2018, 5:58 PM

Take too much time until test is finished...1-5min. If is written in Java take just 1-2 sec

pga4711

05/18/2018, 9:20 PM

Hello, I am very new to app development. I wonder some basic concepta. For example if I have a an app running on a smartphone with 4k resolution with 5 inch and then run the same app on a 4k 10 inch big tablet. In the 90's thinking, the apps would look the same (per pixel thinking). But today the content will look different on the both. Size of buttons, texts ect will be different on the comparing devices. What are these size-concept called?

:android: 2

:google: 8

:stackoverflow: 4

henrytao

05/20/2018, 1:55 AM

Hi all, if you are using LiveData, these extensions can be useful

val liveData: MutableLiveDataBoolean = MutableLiveData()
liveData
  .distinct()
  .filter { it == false }
  .map { true }
  .nonNull()
  .observe(lifecycleOwner, { result ->
    // result is non-null and always true
  })

Check it out: https://medium.com/@henrytao/chaining-livedata-like-rxjava-with-kotlin-extension-e3a2c15ac11

👍 3

Title

henrytao

05/20/2018, 1:55 AM

Hi all, if you are using LiveData, these extensions can be useful

val liveData: MutableLiveDataBoolean = MutableLiveData()
liveData
  .distinct()
  .filter { it == false }
  .map { true }
  .nonNull()
  .observe(lifecycleOwner, { result ->
    // result is non-null and always true
  })

Check it out: https://medium.com/@henrytao/chaining-livedata-like-rxjava-with-kotlin-extension-e3a2c15ac11

👍 3

ghedeon

05/21/2018, 5:51 PM

nice job! What would be the final goal of such effort? To get rid of RxJava? I'm using both just to be in sync with android updates, but honestly, it's hard to justify LiveData presence when you already have Rx. The out of the box lyfecycle management is just a matter of one line from AutoDispose library or similar.

View count: 1