kotlinlang #android

Ah, no I invalidated caches and restarted within Android studio. I think the combination of gradle version, kapt, build tools, etc, etc along with Android Studio 3.0 broke the build entirely

dragas

10/26/2017, 8:01 AM

In other news, the update broke my debugger watched variables.

https://i.imgur.com/27zZNih.png▾

langara

10/27/2017, 7:51 AM

Hi there, check out my second blog post: https://blog.elpassion.com/create-a-clean-code-app-with-kotlin-coroutines-and-android-architecture-components-part-2-4f585050d7d7

👍 6

Paul Woitaschek

10/27/2017, 10:11 AM

0,23123

ramonsgds

10/29/2017, 11:26 PM

How to get current local date and time in Kotlin?

:google: 2

itsJoseph

10/30/2017, 8:40 AM

hello, i want to store some data in my app. can you suggest some storage that i can try? recently using sharedPreference

:stackoverflow: 4

drulabs

10/30/2017, 8:47 AM

Try realm or object box (beta)

itsJoseph

10/30/2017, 9:06 AM

okay sir, gonna check on those. thanks!

feroz_baig

10/30/2017, 1:10 PM

Do I need to uninstall existing AS manually?

anderson.faro

10/30/2017, 7:17 PM

Help me "Variables debug info not available"😡

🙄 1

ramonsgds

10/31/2017, 12:47 AM

@neuber, make sure you have

apply plugin: 'kotlin-android-extensions'

on your build.gradle(Module:app)

ramonsgds

10/31/2017, 12:49 AM

Quick doubt. When iterating like:

for person in list[position].persons

, is

person

another variable created and thus passed by value or is it really list[position].person[some_index] behind the scenes?

edwardwongtl

10/31/2017, 3:39 PM

I think it is related to auto-boxing,

is being treated as Java primitive, while applying

toInt()

forces the boxing to a

Integer

The weird thing is that Kotlin should be able to do this automatically, maybe you can try to fire a bug

rkeazor

11/02/2017, 1:21 AM

Yo will the KotlinConf be live streamed?

anstaendig

11/02/2017, 8:05 AM

And what kind of architecture do you prefer for your [Model]VVM

gildor

11/03/2017, 6:21 AM

IMHO Room now the best solution for sqlite. It depends on case. Sqlite and Realm are very different

oday

11/03/2017, 11:23 AM

but yea im not going to include a whole lib for 2 letters

11/04/2017, 4:38 PM

the IDE has not been changed in any way yet

smilecs

11/05/2017, 10:34 AM

hello please i need direction on some syntax i usually unwrap optionals this way want to know if am right in doing so or not.

userData.token = response.body()?.token!!

preslav

11/06/2017, 9:26 AM

Hi, I am trying to inject field with Dagger 2 into a singleton, that I have implemented with object but it fails with "Dagger does not support injection into static fields" because fields in kotlin objects are treated as static. Is it possible to inject it somehow

Greg Stepniewski

11/06/2017, 9:32 AM

@Minty why not

btn_list[i-1].isChecked = true/false

👍🏼 1

Slackbot

11/06/2017, 10:39 PM

This message was deleted.

:stackoverflow: 2

agrosner

11/07/2017, 1:07 AM

I think you can call them on an instance of View too

preslav

11/07/2017, 9:45 AM

Did anyone experience this Kotlin plugin error "Kotlin threw an uncaught KotlinFrontEndException." I am using Android Studio 3.0

oday

11/07/2017, 10:32 AM

any idea why I’m getting this exception when trying to use Room? http://snpy.in/kK4ueW this is the file in question https://github.com/Odaym/Snipit-Kotlin/blob/master/app/src/main/kotlin/com/om/snipit/dagger/BaseModule.kt#L20

oday

11/07/2017, 2:41 PM

I have a crash happening from Android code itself, https://hastebin.com/analuxegis.nginx this happens when I press any of the list items that I’ve set up, while trying to setup an ItemTouchHelper https://github.com/Odaym/Snipit-Kotlin/tree/master/app/src/main/kotlin/com/om/snipit/ui the items load just fine, but pressing on any one of them produces that internal error, not related to any of my files

Paul Woitaschek

11/07/2017, 9:43 PM

Even if I delte that file manually from the build folder it just creates it again upon build, till I clear the whole module

phendrome

11/08/2017, 9:33 AM

What would you fellas recommend if you wanna get started with Android development with Kotlin? Any specific guides/tutorials?

czuckie

11/08/2017, 10:39 AM

Hey guys 👋 can someone clarify something for me, I've been trying to give coroutines a go, but I feel how I've got it working might not be 100% right

Minty

11/08/2017, 11:26 AM

I want to use a json file with a list containing a lot of lists. Each child list contains two unicode strings. I want to be able to access a random list using my Android app

Title

Minty

11/08/2017, 11:26 AM

I want to use a json file with a list containing a lot of lists. Each child list contains two unicode strings. I want to be able to access a random list using my Android app

czuckie

11/08/2017, 11:36 AM

@Minty Start with a small representation of your data structure, e.g.:

{
  "questions": [
    {
      "q": "q1",
      "a": [
        "a1",
        "a2",
        "a3"
      ],
      "ca": 1
    },
    {
      "q": "q2",
      "a": [
        "a1",
        "a2",
        "a3"
      ],
      "ca": 0
    }
  ]
}

And get your system parsing that correctly, then work on selecting random questions from that

then you can scale up and figure out how things may work

you might find, if you have tons of questions, it will be worth while ingesting them into a SQLite database instead of parsing JSON every time you want to get a selection of questions

Minty

11/08/2017, 11:38 AM

[["Q1.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Discussion Method can be used when: \n (A) The topic is very difficult\u00a0 (B) The topic is easy \n (C) The topic is difficult\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (D) All of the above \n ", "C"], ["Q2.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Which of the following is a teaching aid? \n (A) Working Model of Wind Mill\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (B) Tape Recorder \n (C) 16mm Film Projector\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (D) All the above \n ", "D"],

My data is more like this

czuckie

11/08/2017, 11:39 AM

what do you think of the data structure?

Minty

11/08/2017, 11:40 AM

It's like [["Question1 and choices", "Answer"],["Q2","A"]

czuckie

11/08/2017, 11:40 AM

are you in control of the data structure?

or has a client given it you?

Minty

11/08/2017, 11:41 AM

It's a question paper data that I extracted using regex from a text file

I converted it to json in Python

data = []

for r in re.findall(r"Q\d+.*?(?=Q\d+)", soup.text, flags=re.S):

    data_qa = []

    rs = re.findall(r"Q\d+.*?(?=Answer.*?\:.*?[a-dA-D])", r.strip(), flags=re.S)
    ra = re.findall(r"Answer.*?\:.*?[a-dA-D]", r.strip(), )

    for rse in rs:
   #     print rse
        data_qa.append(rse)



    for rsa in ra:
        if ra.index(rsa) == 0:
#            print("The answer is "+ rsa.replace("Answer", "").replace(":", "").strip())
            data_qa.append(rsa.replace("Answer", "").replace(":", "").strip())
  #  print "__________________________________________________________________"
    data.append(data_qa)

for d in data:
    if len(d)<2:
        data.remove(d)
        print d

jdump = json.dumps(data)

with file("qNa.json", "w+") as f:
    f.write(jdump)

czuckie

11/08/2017, 11:42 AM

ok cool, I would recommend for your own sanity sticking with either \u00a0 or \n but not both 😄

this shouldn’t be too tough though

each of the questions could be represented nicely using a

data class Question(val question:String, val answer:String)

Minty

11/08/2017, 11:43 AM

So is the above representation any good for quiz type things

[["Question1 and choices", "Answer"],["Q2","A"]

czuckie

11/08/2017, 11:43 AM

given that you’re scraping it from a text block, it’ll have to do

the reason I was digging was, if you had the data in a format of question and then a list of answers and the correct answer

you could make the quiz more dynamic and randomise the order of answers etc

but since the question answers are encoded in the question, that’s not really viable

Minty

11/08/2017, 11:44 AM

I'm supposed to create the

data class

outside

oncreate

right? Can I do it in the main activity classs?

czuckie

11/08/2017, 11:44 AM

you can yeah

Minty

11/08/2017, 11:46 AM

But I can call data using

index

in a list. How do I do that with a data class. I still don't understand the concept of data class. i guess I'll have to look it up

czuckie

11/08/2017, 11:46 AM

class MainActivity : AppCompatActivity() {

    data class Question(val question: String, val answer: String)

    fun parseQuestions(rawQuestionJson: String): List<Question> {
        TODO("Parse json")
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        parseQuestions("[[\"Question 1\",\"A\"],[\"Question 2\",\"B\"]]")
    }
}

for example

so if you imagine

class Question(val question:String, val answer:String)

if I did

val q1 = Question("q1", "a")
val q2 = Question("q1", "a")
if (q1 == q2) {
   println("They are equal")
}

‘they are equal’ would not be printed

if I used a data class, kotlin will provide equality methods making that pass

data classes are useful for identifying clumps of data that have a particular meaning

once you parse the JSON, you can then go about randomising access to the list

Minty

11/08/2017, 11:49 AM

How do I dynamically create q1, q2? Would I parse json on the fly and get the data index I want and assign it to q1

data[2] #question3

czuckie

11/08/2017, 11:50 AM

how many questions are you dealing with?

Minty

11/08/2017, 11:50 AM

I did a len(data) there seem to be 1457

czuckie

11/08/2017, 11:51 AM

that’s an impressive amount of questions

you wouldn’t want to parse that everytime you wanted a question

I’d definitely consider whacking the questions in a database, BUT

Minty

11/08/2017, 11:51 AM

Question papers from 2004 -2017 lol

czuckie

11/08/2017, 11:51 AM

you should be able to get away with

private fun parseQuestions(rawQuestionJson: String): List<Question> {
        val result = mutableListOf<Question>()
        val questionArray = JSONArray(rawQuestionJson)
        for (i in 0..questionArray.length()) {
            val question = questionArray.getJSONArray(i)
            result += Question(question.getString(0), question.getString(1))
        }
        return result
    }

line by line, we create a mutable list to store questions in. We then parse the input JSON (we know it’s a JSONArray) We then iterate over all the child arrays We then add a new Question object to our result list (which we can do because it’s mutable) consisting of the two strings in the child question json array object We then result the result

Minty

11/08/2017, 11:54 AM

So, you add created Question object instances to list. That was what was bothering me. Thanks. BTW is JSONArray an inbuilt function?

czuckie

11/08/2017, 11:54 AM

class MainActivity : AppCompatActivity() {

    data class Question(val question: String, val answer: String)

    private fun parseQuestions(rawQuestionJson: String): List<Question> {
        val result = mutableListOf<Question>()
        val questionArray = JSONArray(rawQuestionJson)
        for (i in 0..questionArray.length()) {
            val question = questionArray.getJSONArray(i)
            result += Question(question.getString(0), question.getString(1))
        }
        return result
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var tenQuestions = parseQuestions("[[\"Question 1\",\"A\"],[\"Question 2\",\"B\"]]").shuffled().take(10)
        
        TODO("Display ten questions")
    }
}

JSONArray is part of

org.json

which is shipped with android

var tenQuestions = parseQuestions("[[\"Question 1\",\"A\"],[\"Question 2\",\"B\"]]").shuffled().take(10)

may look like black magic but

var tenQuestions = parseQuestions("...JSONHERE...")
   .shuffled() // Randomises the order of list items
   .take(10) // Take the first 10 items from the list

assuming you want a random collection of questions!

subjecting someone to 1407 questions is going to be brutal lol

if this is to help you revise etc

I would really investigate the possibility of teasing out the answer from the questions

it’ll help you learn the right answer, rather than the right letter 😉

Minty

11/08/2017, 11:57 AM

It's a multiple choice. I have created logic for buttons. I check the string A, B,C,D and set the answer int to ,1,2,3,4 and check in Button

What do you mean by teasing out?

czuckie

11/08/2017, 11:58 AM

so if all the questions take the format

“This is a question that needs to be answered by one of the following answers: A) Answer A B) Answer B C) Answer C D) Answer D” Correct Answer: C Then I would parse the input data to extract “This is a question that needs to be answered by one of the following answers” the individual answers The correct answer

and I’d transform that into the format I explained above

then you could randomise the display of the answers

since you know what the correct answer is, you always know that if you display answer C first, the first button would be the correct one

any who ! Lunch time, ask questions though!

Minty

11/08/2017, 12:00 PM

I can maybe give a option to display answer too. But my main focus is to build a quiz. This is my first Kotlin project and I'm in love with kotlin already

Oh! You mean randomising the order of the choices?

That'll be useful but I have to parse the data first. Regex to the rescue.

But I want to build a simple working project first and add features later

Since this is my first project, I want to take it easy and build the simple parts first (a proof of concept) and add features later

BTW what do I have to import for JSONArray?

Never mind, imported it

czuckie

11/08/2017, 1:04 PM

your approach is perfect

build the simplest thing first

go end to end

then beef it up as you go

agile all the way 👍

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