Questions tagged [kotlin]
Kotlin is a statically typed programming language that compiles to JVM bytecode, JavaScript, or native binaries.
258
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Code for working with a tasks in To-Do Android application
Overview
I am working on an android To-Do app. I have a piece of code that I use to work with tasks.I am new to android development and want to grow, so I would really like someone to rate my code and ...
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Create two teams from a list of players with minimum of one goalkeeper per team
I wanted to create a simple method that creates two random teams for football/soccer match from a list of players with a requirement that the goalkeepers should be in different teams (so that one team ...
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2
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Instantiating Person objects using the builder pattern
I'm trying to make a safe builder using Kotlin that can be partially built and then copied, perhaps multiple times, to avoid repetition. Note that the properties that are reused aren't always the same ...
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API for general boolean flag set
Very simple question. Imagine are designing library API, where you want to provide way to switch boolean flag. Typically to disable or enable a functionality. For argument's sake, let's say it's ...
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Iterating through ArchiveInputStream or structures having a 'next'-accessor [closed]
ArchiveInputStream is from apache-commons compress. it is an InputStream. nextEntry is the only method for traversing the stream i've found the while loop is IDE ...
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Multi-dimensional arrays exercise: Introduce married couples to each other
Following idea: There are three married couples and they have to be introduced another.
I have implemented this solution:
...
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Constructing a DSL with properties instead of functions, for use in a type-safe pseudo-builder
As one step in a larger builder setup, I need to build a small collection of objects, each with a small number of required attributes, and each of those with a small set of possible values. The actual ...
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Replacing type-check with Visitor in Immutable Event-Sourced Aggregate
In my previous question, one of the answers mentioned that I shouldn't be changing behavior based on the Event class
The whole point of classing is that you can get result without having to decide ...
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Matrix implementation in Kotlin
I put this together for a task and thought some feedback would be useful.
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Using Functional programming to untangle deeply nested loops (Kotlin)
Problem statement for better understanding:
Let's say we assign a unique number to each alphabet,
a=1, b=2, c=3...z=26
then find the frequency of the sum of each ...
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Aggregate data from a huge list under 50ms
I got this question as a coding challenge and was unable to get it done under 50 milliseconds (my solution takes >100 ms) :D
Would you please review my code and share any idea how to do this within ...
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Signing in with "Remember me" option implemented with Spring and Kotlin
I'm trying to implement authentication with "Remember me" option using Spring and Kotlin. I would really appriciate if someone could help me find potential issues with that implementation as ...
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MutableLiveList class for android
I have wrote a MutableLiveList class for android, similar to existing MutableLiveData, but this class instead handles a list and ...
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554
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Android Tic-Tac-Toe
I have made an Android Tic-Tac-Toe adaptation as a weekend-project.
Here's the Kotlin-code.
MainActivity:
...
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Chess in Kotlin
This is an updated version of my first question:
Chess game in Kotlin
I wrote the following Chess logic in Kotlin and am looking for feedback to make the code cleaner and follow good software design ...
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Chess game in Kotlin
I wrote the following Chess logic in Kotlin and am looking for feedback to make the code cleaner and follow good software design principles. I tried to adhere to object-oriented design.
Some notes:
• ...
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UDP image livestream from Android device to C# desktop application
After searching a lot, on how to do it and not finding any good solutions, I implemented my own UDP livestream from an Android device to a C#/WPF desktop application. It works, however, since I get ...
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A Stateless Immutable Event-Driven DDD Pattern in Kotlin
I've been interested in making fully repeatable, reproducible game states. This led me into the world of DDD, and specifically, the concept of Aggregates + Event Sourcing (although that's not ...
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Rock-Paper-Scissor-Lizard-Spock in Kotlin
I have made a simple Kotlin application called Rock-Paper-Scissor-Lizard-Spock. The application takes in user input and check if belongs to given set of array. If it belongs then it compares user ...
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59
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Linked list that support modifications during iteration
Update:
Fixed last item is not removed during iteration
Fixed clear() during iteration does nothing
Fixed addition of removed item is ignored
The lasted code can ...
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Write a Kotlin-function isPrimeNumber
Exercise:
Write a prime number-test isPrime(num: Int), which for integer m >= 2 checks, if the integer is a prime number or not.
My solution:
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An exercise concering Kotlin Set
Task description:
Declare a function twoInThree(a: Set, b: Set, c: Set), which returns the set of all elements, which are contained in exactly two of the three given sets a, b, c.
My solution:
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Write a Kotlin function "commonPrefix"
Task description:
Write a function commonPrefix, which takes two strings as parameter and returns the common prefix.
Example: parameters ...
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Generating multiplication questions and answers for a quiz style app
See this link for previous post on this subject Generating mathematical questions and answers
I have an Android quiz app that I am building to learn kotlin / android app development. Here is an object ...
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Are these Unit tests OK or am I implementing an antipattern or not following best practices
I am testing a Spring boot service using JUnit 5 and Mockito. I haven't spent much time on unit testing in the past so I'm not sure if I'm accidentally implementing an anti-pattern or not following ...
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Generating mathematical questions and answers
I have an Android quiz app that I am building to learn kotlin / android app development. Here is an object I have which acts as one of many question builders.
Is there a better way of writing this?
<...
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104
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Read database from IO context and update UI from Main context in Kotlin
Still a bit new to Kotlin and coroutines, so I want to learn best practices. The following code seems to work as expected in it's original context, though the naming has been tweaked here. The list of ...
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Prime number sequence supporting repeated iteration
I'm a long-time Java programmer, but recently I decided to give Kotlin a try. So far, I'm loving the language features, it feels much more expressive than what I'm used to. As practice, I wrote this ...
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Composing IHandler<T>
Here is a composable IHandler<T> implementation. Any ideas on how to make it shorter and get rid of exception being thrown?
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Kotlin fake properties and their usage
I had an idea recently of simplifying some of the code I already have in my Android app that uses Kotlin. I somewhat new to Kotlin, so any opinion would be very appreciated.
Before giving you what ...
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View Binding with Base Classes
UPDATE: After getting "a kind of" affirmation from various platforms( my discussions on twitter, reddit, other stack overflow posts,etc) I have written an article on this style of view ...
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Which of my string indexing functions in Kotlin is semantically closer to my Java one?
I have a working string indexing method in Java and did convert in Kotlin.
All methods shown below produce the same result but as I am really new to the Kotlin language I wanted to ask which of my two ...
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2D Array Word Search: Complexity and Optimization
🧩 Objective
Determine whether a given word is contained in a 2D Array word search.
🔎 Question
1. What are the time and space complexities of the current algorithm?
Time complexity
Linear: \$O(2(r * ...
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Generate unique string permutations recursively
🧩 Objective
Write a recursive method for generating all permutations of an input string. Return them as a set.
See: Recursive String Permutations - Interview Cake
🔎 Questions
1: How does the ...
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Optimize a tile rendering algorithm for Swing Canvas
I have an algorithm that I use to render a text GUI using Swing's Canvas, it looks like this in practice:
My goal is to reach 60 frames per second for a full HD ...
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Basic REST API in Ktor
I have written a basic REST endpoint in Ktor and would like some pointers.
Application.kt
...
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Contains all elements and duplicates are taken into account
The idea is to have a function which checks if all elements in a list are contained in another list. But not just the containedness has to be true, but also the times of containedness.
One could say ...
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A better understanding for separation of concerns. Android; Kotlin
I am an Android developer with only 5 months of experience. I am still learning and trying to do my best.
Right now I am interested in concept of ...
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A Concurrent Tree implementation with consistent snapshot capability
I have a tree in my application from which I need to periodically take a snapshot. I've been using locks so far, but after running into a few deadlock issues I decided to create a lock-free ...
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How to speed up drawing process of output from .tflite model
I have piece of code where I draw output from model pixel by pixel:
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String tuple serializer
Please review my class which is responsible of serialization and deserialization of the StringTuple data class.
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Representation of data record for an employee (generic method vs design pattern)
preface: I have a part of my code that is repeated more than once and I want to create a generic method or follow a design pattern to make the code cleaner.
What I'm trying to achieve is:
I have a ...
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241
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Bloomfilter in Kotlin
I would like a code-review. Not so much on if the implementation is good or effecient, it's probably not, more on code style and readability.
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Generic RecyclerView Adapter in Kotlin
I've just finished implementing a Generic RecyclerView adapter in my Android app, written in Kotlin.
BaseAdapter.kt:
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Arithmetic Parser in Kotlin
I don't really have a problem. But, it's my first time using Kotlin for any project, so I want to know if there is any problem in my code or my code can be made cleaner.
This is an arithmetic parser ...
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Double LinkedList Deep Copy in Kotlin with Generics and Thread Safety
Goal
Return a deep copy of a double LinkedList.
Each node also contains an additional random pointer, potentially to any node or null.
Code to start
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Game of Life in Kotlin
I've implemented a Game of Life in Kotlin.
There are some major requirements on this solution:
Purely object-functional production code.
As close to an infinite universe as possible.
File ...
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N-elements byte array to integer conversion (little/big endian and signed/unsigned)
I'm trying to come up with a function to convert byte arrays to their integer representation, using both
endianness, and with a signed/unsigned option.
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Kotlin Stack using an ArrayList to compare and remove elements
Is this a performant strategy to implement a stack in Kotlin to compare and delete values?
Expect
Create a stack in order to compare an array of asteroids (ASTs) and handle collisions (deletions), ...
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