---
title: "From Double-Click Prevention to In-Flight Deduplication"
url: https://daily.dev/posts/from-double-click-prevention-to-in-flight-deduplication-dogi5ksdl
source_url: https://proandroiddev.com/from-double-click-prevention-to-in-flight-deduplication-499976d3a00d
type: article
source: "ProAndroidDev"
published: 2026-08-21T14:42:55.213Z
updated: 2026-08-21T15:03:43.017Z
tags: ["android", "kotlin"]
reading_time: 12
upvotes: 0
comments: 0
language: en
---

> ## Documentation Index
> Fetch the complete documentation index at: https://daily.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# From Double-Click Prevention to In-Flight Deduplication

**[ProAndroidDev](https://daily.dev/sources/pand)** · 12 min read · 0 upvotes · 0 comments

## Summary

A deep dive into evolving a naive double-click prevention fix into a robust in-flight deduplication mechanism for Android apps using Kotlin coroutines. The piece traces the journey from time-based debouncing, to tracking a single Job's lifecycle, to a scalable, reusable UniqueJobTracker backed by a ConcurrentHashMap that uses atomic compute operations and CoroutineStart.LAZY to guarantee only one execution of a keyed operation is active at a time, applicable beyond ViewModels to any owner of async work.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://proandroiddev.com/from-double-click-prevention-to-in-flight-deduplication-499976d3a00d>

## Questions this post answers

### How do I prevent a coroutine job from starting before I know if it's a duplicate operation?

Use CoroutineStart.LAZY when launching the coroutine so the job exists but its body does not run until explicitly started. This creates a window where a tracker can register the job, check if the key is already owned, cancel it if it is a duplicate, and only call start() if it wins ownership, avoiding partial execution before the ownership decision.

_daily.dev surfaces patterns like this for developers building safer async job tracking in Kotlin._

### Why is ConcurrentHashMap.compute needed instead of a plain containsKey check before inserting a job into a map?

A plain containsKey followed by an insert is not atomic, so two concurrent events can both see an empty slot and both insert their job, defeating deduplication. ConcurrentHashMap.compute makes the check-and-update atomic for a given key, ensuring only one job becomes the owner while the other gets cancelled instead of registered.

_developers hardening concurrent Kotlin code against race conditions can track patterns like this on daily.dev._

### Why does debouncing a button click fail to prevent duplicate async operations in Android?

Debouncing protects the UI for a fixed time window, but the underlying operation's actual duration can exceed that window, letting a second click trigger a duplicate operation after the button re-enables. It also fails when navigation or other side effects complete after the debounce expires, causing duplicate navigation or crashes. Tracking the operation's actual Job lifecycle solves this instead.

_daily.dev helps developers compare debouncing against job-based tracking when designing reliable async click handling._

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---

Tags: [#android](https://daily.dev/tags/android), [#kotlin](https://daily.dev/tags/kotlin)

[View this post on daily.dev](https://daily.dev/posts/from-double-click-prevention-to-in-flight-deduplication-dogi5ksdl)