kotlinlang #codereview

method takes an exception, the other takes a callback with the exception as the first arg, so I don’t understand why it wouldn’t be able to figure that out…

oday

05/08/2018, 11:10 AM

can I post code here with a bug?

oday

05/08/2018, 11:12 AM

why does line 6 get called multiple times? https://pastebin.com/tz0gkZrg many many times first when I insert 1 row and the count is 1, it gets called twice, and then after that the calls just keep increasing pastes the count 6 or 10 times

Hamza

06/11/2018, 8:21 AM

how can i make this easier for myself?

Ayden

06/14/2018, 2:42 PM

Would you mind to take a look one my

SwipeRefreshLayout

? Am I doing something redundant?

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/*
    Fetching data from Firebase and
    passing the value to Adapter
    */
val addValueEventListener = firebaseReference.addValueEventListener(object : ValueEventListener {
    override fun onCancelled(p0: DatabaseError) {
        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }

    override fun onDataChange(p0: DataSnapshot) {
        if (p0!!.exists()) {
            val vibeList = mutableListOf<Vibes>()
            // V stands for Vibe
            for (v in p0.children) {
                val vibe = v.getValue(Vibes::class.java)
                vibeList.add(vibe!!)
            }
            recyclerView.adapter = VibeAdapter(vibeList)
        }
    }

})


/*
    Fetch data from Firebase and
    passing the value to Adapter whenever
    swipe refresh triggered
    */
swipeRefreshLayout.setOnRefreshListener {
    val addValueEventListener = firebaseReference.addValueEventListener(object : ValueEventListener {
        override fun onCancelled(p0: DatabaseError) {
            TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
        }

        override fun onDataChange(p0: DataSnapshot) {
            if (p0!!.exists()) {
                val vibeList = mutableListOf<Vibes>()
                // V stands for Vibe
                for (v in p0.children) {
                    val vibe = v.getValue(Vibes::class.java)
                    vibeList.add(vibe!!)
                }
                recyclerView.adapter = VibeAdapter(vibeList)
            }
        }

    })
}

snowe

06/16/2018, 4:42 PM

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var resultValidator = testExecutor.whenever(wheneverCommand!!)
        resultValidator = expects.events?.let { resultValidator.expectEvents(*it.toTypedArray()) } ?: resultValidator
        resultValidator = expects.eventsMatching?.let { resultValidator.expectEventsMatching(it) } ?: resultValidator
        resultValidator = expects.returnValue?.let { resultValidator.expectReturnValue(it) } ?: resultValidator
        resultValidator = expects.returnValueMatching?.let { resultValidator.expectReturnValueMatching(it) } ?: resultValidator

Hamza

06/21/2018, 2:47 PM

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"INVALID REQUEST"                     -> html("The PayPal API failed us. INVALID_REQUEST")
      "AUTHENTICATION_FAILURE"              -> html("I'm sure we authenticated. Right, guys? AUTHENTICATION_FAILURE")
      "NOT_AUTHORIZED"                      -> html("What do you mean we are not authorized? &gt;:( NOT_AUTHORIZED")
      "RESOURCE_NOT_FOUND"                  -> html("Guys, we need to update our API. RESOURCE_NOT_FOUND")
      "METHOD_NOT_SUPPORTED"                -> html("This wasn't suppose to happen... METHOD_NOT_SUPPORTED")
      "MEDIA_TYPE_NOT_ACCEPTABLE"           -> html("This wasn't suppose to happen... MEDIA_TYPE_NOT_ACCEPTABLE")
      "UNPROCESSABLE_ENTITY"                -> html("Guys, we broke PayPal! UNPROCESSABLE_ENTITY")
      "RATE_LIMIT_REACHED"                  -> html("We've reached max capacity. Please try again later. RATE_LIMIT_REACHED")
      "INTERNAL_SERVICE_ERROR"              -> html("Look. PayPal. You need to fix your system. INTERNAL_SERVICE_ERROR")
      "SERVICE_UNAVAILABLE"                 -> html("PayPal is not available at the moment. Please try again later. SERVICE_UNAVAILABLE")

is there a better way?

ianbrandt

06/25/2018, 3:25 AM

Been practicing with Uncle Bob's Prime Factors kata (http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata). Any improvements here, given the absence of C-style

for

loops in Kotlin? Perhaps a functional approach?

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fun primeFactorsOf(integer: Int): List<Int> {
	val primeFactors = mutableListOf<Int>()
	var n = integer
	var divisor = 2
	while (n > 1) {
		while (n % divisor == 0) {
			primeFactors.add(divisor)
			n /= divisor
		}
		divisor++
	}
	return primeFactors
}

For comparison, a Java implementation with C-style loops:

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public static List<Integer> primeFactorsOf(int integer) {
	List<Integer> primeFactors = new ArrayList<>();
	for (int divisor = 2; integer > 1; divisor++)
		for (; integer % divisor == 0; integer /= divisor)
			primeFactors.add(divisor);
	return primeFactors;
}

Daniel

06/25/2018, 7:51 PM

Suppose I want to invoke a lambda given to a mock (

delayer

) then I would use (this is a question):

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argumentCaptor<() -> Unit>().apply {
            whenever(delayer.delay(capture())).thenAnswer { 
                firstValue()
            }
        }

? Now suppose I only want to invoke the lambda a defined number of times because the code calles

delay(...)

recursively until the user stops it. How would I do this? I came up with:

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argumentCaptor<() -> Unit>().apply {
            var invocationCount = 0

            whenever(delayer.delay(capture())).thenAnswer {
                if(invocationCount < times) {
                   ++invocationCount

                   firstValue()
               }
           }
        }

But that does not seem like a clean solution

Ayden

06/26/2018, 2:06 PM

Is there a way to write this line of code in a better way?

val httpLoggingInterceptor = HttpLoggingInterceptor().level = HttpLoggingInterceptor.Level.BODY

Hamza

06/29/2018, 4:22 PM

any suggestions on this snippet?i feel i did pretty well but there are always some tricks kotlin has up its sleeve ¯\_(ツ)_/¯

Hamza

06/29/2018, 4:31 PM

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println("hello".apply {
		replace("h", "H")
	})
}

Shawn

07/03/2018, 5:48 AM

maybe I’m missing some context but it seems like you could at least simplify it to

buttonRegister.isEnabled = ! (isEmpty(email) && isEmpty(password) && isEmpty(confirmPassword))

but

is a source of contention among a lot of developers since it’s easy to miss or forget to use

Ayden

07/03/2018, 7:04 AM

@Shawn may I know what is the correct or best way of doing it?

kristofdho

07/12/2018, 3:04 PM

fillAdIds

is also only used once so why define a function for it

👍 1

☝🏽 1

Andreas Sinz

07/12/2018, 4:19 PM

IMO your code is far more complex than it needs to be (e.g. temporarily storing data inside the class

tempAdIds

currentAdId

, ...) which can lead to nasty race conditions/other kind of bugs later on

robin

07/24/2018, 1:53 PM

Any ideas, or does this look good enough for you? (Please disregard the fact that it doesn't use the subtraction rule to make the numerals shorter)

DecimalToRoman_kt.kt

tianhao

07/25/2018, 6:01 AM

Hi, guys below is my code to send a message to Kafka using Java API, I would like to do a code review and meanwhile for producer value a got a warning like

accessing non-final property in constructor

not sure how is the fix for that? Thanks

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class KafkaService {

  val producer: KafkaProducer<String, String>

  init {
    val props = Properties()
    props[ProducerConfig.BOOTSTRAP_SERVERS_CONFIG] = "127.0.0.1:9092"
    props[ProducerConfig.CLIENT_ID_CONFIG] = "DemoProducer"
    props[ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG] = StringSerializer::class.java.name
    props[ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG] = StringSerializer::class.java.name

    producer = KafkaProducer(props)
  }

  fun sendToKafka(topic: String, message: String) {
    val producerRecord: ProducerRecord<String?, String> = ProducerRecord(topic, null, message)
    producer.send(producerRecord)
  }
}

Ayden

07/27/2018, 9:21 AM

Just one file.

x80486

08/07/2018, 2:50 AM

Hello folks! Is there a better way to do this?

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class Response(val message: String, val path: String) {
  val timestamp: Long = Instant.now().toEpochMilli()

  var status: Int = 0

  lateinit var error: String

  companion object {
    fun clientError(message: String, path: String): Response {
      return Response(message, path).apply { status = 400; error = "Bad Request" }
    }

    fun serverError(message: String, path: String): Response {
      return Response(message, path).apply { status = 500; error = "Internal Server Error" }
    }
  }
}

twisterrob

08/09/2018, 11:42 PM

?.

if

Which one is better in the following example and why? (open to improvements)

louiscad

08/11/2018, 8:46 AM

Hi, anyone knows how I can make the following snippet more safe?

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/** Matches [android.support.v7.app.AppCompatViewInflater.createView] content. */
val appCompatViewFactory = { clazz: Class<out View>, context: Context, _: Style<out View>? ->
    when (clazz) {
        TextView::class.java -> AppCompatTextView(context)
        Button::class.java -> AppCompatButton(context)
        ImageView::class.java -> AppCompatImageView(context)
        EditText::class.java -> AppCompatEditText(context)
        ...
        else -> null
    }
}

The issue is that there's no type check, I could return anything for anytype and the compiler won't fail. I want to make sure each when branch returns an object of the type of the case on which it matched.

kotlin_questions

08/11/2018, 4:02 PM

But i could also do this on a Note level instead of a field level what would be a good design here?

griffio

08/12/2018, 7:11 PM

@antoin_m Yes - from my understanding it will work as expected with the type simply as the Vec sealed class. No extra casting is needed. The compiler will correctly show the “exhaustive check” if you add another data class.

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operator fun Double.times(vec: Vec) = when (vec) {
    is Vec2 -> vec.copy(this * vec.x, this * vec.y)
    is Vec3 -> vec.copy(this * vec.x, this * vec.y, this * vec.z)
}

Andreas Sinz

08/12/2018, 7:47 PM

@antoin_m and the

as T

-cast is needed, because the return type of your

when

Vec

and not

Ayden

08/13/2018, 7:07 AM

Hi guys. Is there a way to make this code become shorter and efficient?

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if (TextUtils.isEmpty(name)) {
        textInputName.isErrorEnabled = true
        textInputName.error = "Name cannot be empty."
    }
    if (TextUtils.isEmpty(email)) {
        textInputEmail.isErrorEnabled = true
        textInputEmail.error = "Email cannot be empty."
    }
    if (TextUtils.isEmpty(password)) {
        textInputPassword.isErrorEnabled = true
        textInputPassword.error = "Password cannot be empty."
    }
    if (TextUtils.isEmpty(password)) {
        textInputConfirmPassword.isErrorEnabled = true
        textInputConfirmPassword.error = "Confirm password cannot be empty."
    }
    if (!Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
        textInputEmail.isErrorEnabled = true
        textInputEmail.error = "Email format does not valid."
    }
    if (!(password.length >= 8)) {
        textInputPassword.isErrorEnabled = true
        textInputPassword.error = "Password length must be greater than 8 character."
    }
    if (!(confirmPassword.length >= 8)) {
        textInputConfirmPassword.isErrorEnabled = true
        textInputConfirmPassword.error = "Confirm password length must be greater than 8 character."
    }
    if (!(password.equals(confirmPassword))) {
        textInputConfirmPassword.isErrorEnabled = true
        textInputConfirmPassword.error = "Confirm Password does not match with Password"
    }
}