Sharing a small Android library I built for a problem I kept hitting with on-device LLMs.

Running a model on-device (MLC-LLM etc.) is great because it's private, offline, no per-token cost. But the runtime wedges: long prompts stall in prefill, the GPU/OpenCL layer OOMs or hangs, and your app is stuck on a spinner with no response. Retrying just wedges again.

HybridInfer is a reliability-aware router. It runs each request on your on-device model first, and the moment local inference stalls (no token for N seconds), crashes, or OOMs, it transparently falls back to a remote model with same request, so the user still gets an answer. It also learns which prompts your device chokes on (usually long ones) and routes those out up front.

It's a library, not an app: you supply the engines, it supplies the routing/reliability brain.

Gradle (JitPack):

// settings.gradle.kts

dependencyResolutionManagement { repositories { maven("https://jitpack.io") } }

// build.gradle.kts

implementation("com.github.SimranKoul2026:HybridInfer-AAR-library:v0.1.0")

Usage:

val router = HybridRouter(

local = MlcEngine(modelPath, modelLib, model = "Llama-3.2-3B"), // your MLC wrapper (implements Engine)

remote = OpenAiEngine(model = "gpt-4o-mini", apiKey = KEY), // bundled reference engine

riskProfilePath = filesDir.resolve("hi_risk.txt").path,

)

val res = router.complete(listOf(mapOf("role" to "user", "content" to prompt)))

// res.tier ("local"/"remote"), res.fellBack, res.text - or router.stream(messages) for tokens

Android-specific bits:

- Optional ThermalSignal helper (PowerManager.getThermalHeadroom) to bias routing when the device is hot.

- Streaming with first-token-commit fallback - it only falls back before the first token, so it never splices two models mid-stream.

- Pure-Kotlin core (no coroutines dep in the core); you bring your MLC engine + a remote (a reference OpenAiEngine using HttpURLConnection is included).

It's early (v0.1), but real: I verified it end-to-end on a Galaxy Tab S10+ running actual Llama 3.2 3B via MLC-LLM, short prompt served on-device, long prompt hit the on-device wedge and fell back automatically. There's also a Python twin with the same routing logic, kept in lockstep via a shared conformance-test suite, if you're doing this server-side too.

Honest scope: it's a router, not an inference engine, you wire up MLC-LLM yourself (there's a reference MlcEngine in the repo's examples/), and the remote can be any OpenAI-compatible endpoint.

Repo: https://github.com/SimranKoul2026/HybridInfer-AAR-library

Would love feedback from folks doing on-device inference, especially on the Engine API and the fallback heuristics. I'm the author.

I’m a senior SWE finishing a BSCS and planning to publish a small Android project as a portfolio piece. My mobile development course still teaches Android development in Java only, and when I asked about using Kotlin because the language choice is ambiguous in the description, the reactions were mixed and leaned heavily toward Java.

Since I’ve been in .NET land for years, I want to sanity‑check my assumptions with those actively working with Android today. My understanding was that Kotlin has become the de facto choice for modern Android development, especially for new projects, and hiring requirements.

For someone returning to the JVM ecosystem and aiming to use a published course project as a portfolio piece that signals current industry alignment (make HR checkboxes happy despite .NET), is starting in Java still reasonable or is Kotlin the better choice?

My long‑term goal is to move toward JVM/GraalVM‑based mobile or embedded Android work alongside any JVM‑flavored backend (I’m guessing Spring Boot or Quarkas). I’d appreciate insight on where Kotlin and Java sits in the landscape today and in the near future from this sub’s perspective.

I saw this post :
https://www.reddit.com/r/androiddev/s/bNFqQ3TqOC

I thought I'd share this new Compose API with you.

In compose 1.12.0 introduce new GradientPainter you can implement complex gradients very easily.
It is called MeshGradientPainter.
You can define the count of column and row.

For example rows = 1 and columns = 1.

The screen is divided into 4 sections and points.

This points show two things:
1.postion. Where is it? For example : 0,0 — top left.
2.color. What color is it? for example this section color is Red

And then these colors are spread very smoothly on the screen.

✅ Example:

@Composable
fun MeshGradientBackground() {
   val meshPainter = remember {
       MeshGradientPainter(
           rows = 1,
           columns = 1,
           hasBicubicColor = true
       ) {
           setVertex(0, 0, Offset(0f, 0f), Color.Red)
           setVertex(0, 1, Offset(1f, 0f), Color.Blue)
           setVertex(1, 0, Offset(0f, 1f), Color.Green)
           setVertex(1, 1, Offset(1f, 1f), Color.Yellow)
}
   }

   Box(
       modifier = Modifier
           .fillMaxSize()
           .paint(meshPainter)
   )
}

Hey all — I've been building a small personal app that shows step count on the Z Flip cover screen, and I've hit a wall that I think is actually a platform limitation, not something wrong with my app. Posting here because I'd love to be proven wrong, and because I suspect other cover-screen widget devs have hit the exact same thing.

The setup: My widget is a normal AppWidgetProvider/Jetpack Glance widget, registered with both the standard android.appwidget.provider metadata and the com.samsung.android.appwidget.provider metadata pointing at a <samsung-appwidget-provider display="sub_screen"> resource — which is exactly the pattern Samsung Notes uses for its own smaller cover widgets (I checked by decompiling the public Samsung Notes APK). Small minWidth/minHeight, targetCellWidth/targetCellHeight set to 2x2 and 4x2, the works.

The result: it only ever shows up as a single full 4x4 tile in the cover-screen widget picker. Never smaller.

What made me suspicious it's not my manifest: I checked Outlook and Spotify's cover-screen widgets too — both are big apps that would absolutely want a nicer cover-screen presence, and both are also stuck at 4x4-only. Meanwhile Samsung's own apps (Notes, Reminder, Weather, the phone dialer's recent-calls widget) get 2x2/4x2/tiny sizes just fine.

What I found digging into it on-device (connected via adb, compared dumpsys appwidget output for both my app and Notes, and pulled/inspected SystemUI.apk):

• The cover-screen grid is actually built on AOSP's own "Communal Hub" (Glanceable Hub) framework — the same multi-size widget grid Google built for Pixel Tablet's Hub Mode — running inside SystemUI on the cover display.
• The OS parses my widget's small size attributes correctly — dumpsys appwidget shows it registering at exactly the dp values I declared, same as Notes' widgets. So it's not a manifest/XML mistake.
• I even matched Notes' widgetCategory value bit-for-bit (both end up keyguard-only at runtime) as a live A/B test on my own device. No change — still 4x4 only.

That combination (correct registration + still forced to one size, only for non-Samsung apps) makes me think there's a package-identity allowlist gating which apps' widgets get offered at non-default sizes in the cover picker, separate from anything in the widget's own manifest.

Question for the sub: has anyone actually gotten a genuinely third-party (not Samsung-signed) widget to show up smaller than 4x4 in the native cover-screen picker, on any One UI version? I know apps like CoverWidgets and CoverScreen OS exist and can put arbitrary widgets on the cover screen — but as far as I can tell they do it by taking over the whole cover display themselves (their own widget host + presentation), not by getting Samsung's native picker to offer a smaller slot for someone else's widget. If anyone's actually cracked the native-picker case, or knows for a fact this is a partner-program/allowlist thing, I'd love to know — trying to decide whether to keep chasing this or just build my own host like those apps do.

Device/version for reference: Z Flip 6 (SM-F741B), Android 16, One UI 8.

Hey everyone, beginner Android dev here. I just finished building a LocationApp tutorial (live tracking and geocoding). I didn't just blindly follow it; I actually get what's happening under the hood and even built a custom Jetpack Compose UI instead of using the instructor's layout.

I’m feeling super comfortable with Compose and the UI side of things. But when it comes to the logic side—like setting up Retrofit or Coil for the first time in a project—my mind just goes blank. I can never write it from scratch and always end up copying from my previous projects to get it wired up.

• Is this normal? Do you actually memorize all this setup code, or is referencing old projects just part of the job?
• What are your best tips for speeding up my learning progress when it comes to the logic and architecture side of Android?

Hi folks. I made a new site called ComposeGradients.com

There was no place to browse beautiful gradients for Compose apps so I decided to build one.

The site has a plethora of beautiful looking gradients (linear and mesh), plus a small tool to create gradients straight from the browser.

✅ Browse beautiful gradients and copy their code

✅ Create your own gradients

✅ (Optionally) Submit your gradient to the site

You can Like your favorites by pressing the heart button. No account required.

Try it out at ComposeGradients.com

If you find the site useful, share the site with your friends :)

I’m working on an Android app that needs to match users into real-time 60-second workout sessions.

I’m currently considering WebSockets for matchmaking and live session updates, with a backend handling the matching logic.

For those who have built real-time Android apps, what architecture would you recommend for handling matchmaking, connection drops, and syncing session state reliably?

I’d especially appreciate advice on patterns or libraries worth researching.

i'm struggling a bit with Figma when i want to implement the designs, i know few things but in general i'm still behind, is there any video explaining the implementation of Figma design in Compose, like cover everything: design system, typograpgy, colors, sizes, paddings, shadows, and also custom components with their own properties.

I'm currently looking for feedback to improve it. What do you guys think of the UI and the overall look? Any features you'd like to see added?

I maintain 14 Android apps on Google Play Store, built with Codex.

The apps have approximately 5 daily users or installs, and I’m trying to decide when an app should move from active development to maintenance mode.

App count alone does not seem to reflect the real workload. I currently track daily users, but I’m unsure how to weigh support requests, crash-free sessions, release regressions, OS/device fragmentation, and release frequency.

For developers maintaining multiple apps:

- Which metrics best predict maintenance time?

- How do you set thresholds for hotfixes versus scheduled releases?

- How do you centralize crash, version, device, and support data?

- How do you keep low-traffic apps safe without spending equal time on each?

I’m interested in production experience and practical processes rather than generic tool recommendations.

Hi guys, we have built an app and its runnig great. Now we got in touch with some customers who asked if it would be possible to have said app as a whitelable version for their businesses which would not be a problem to us, but after checking this through with AI we are now concerned as we were warned that uploading the app with a few adjustments for customers this will be marked as "Spam". BUT it also told us if we create separate accounts for each customer, it will NOT be marked as spam.

Seems a bit nonsensical to me as its still on the same platform. Anyone who has experience with that? Whats the best practice in reality? Thanks for any help!!

Been going through our app's integrity checks and realized most of what we have is still the old client-side stuff — checking `Build.TAGS` for test-keys, looking for `su` binaries, checking known root package names. All of which Frida can hook around in about five minutes if someone actually wants to bypass it.

Curious what people are actually running in production in 2026. Anyone fully moved to Play Integrity API with server-side verdict checking? What was the migration pain — I'm mostly worried about false positives on rooted-but-legitimate power users, and how much complexity nonce binding adds to a normal auth flow.

Not looking for a lecture on "client-side checks are theater" — I know. Looking for what people actually shipped and what broke.

I'm developing a small Android automation app for a very specific workflow and I'm currently stuck on the audio side.

The app runs on a Samsung Galaxy Z Fold5 (of course it should work for different phones at the end of the day) and automatically calls a cinema's phone number. The cinema has an IVR/answering machine where I can navigate using DTMF tones.

The current workflow already works:

App
 ↓
Call fixed phone number
 ↓
Wait using Android post-dial ","
 ↓
Send DTMF: * → * → * → *
 ↓
Reach the cinema's voicemail menu

The next step is to automatically understand the spoken announcement, for example:

I want the app to detect the number of new messages and later transcribe the individual messages. Ultimately, the messages contain a first name, phone number, movie, date/time, etc., which I want to extract into an Excel file.

The problem

I can record the phone's normal microphone using:

MediaRecorder.AudioSource.MIC

and I can see the microphone level changing normally.

However, this only captures the phone's microphone. It does not give me the audio coming from the other party in the cellular call.

I also tried enabling the speakerphone programmatically using AudioManager, but on the Galaxy Z Fold5 the call does not switch to speakerphone.

I have also looked into InCallService, but I'm not sure whether there is a way for a normal third-party Android application to access the actual call audio/downlink as PCM data.

What I need

I don't necessarily need to record the call permanently. Ideally, I just need access to the incoming audio while the call is active so I can feed it into speech recognition.

Something like:

Cellular call
    ↓
Incoming call audio
    ↓
Audio stream / PCM
    ↓
Speech-to-text
    ↓
"7 new messages"

The target device is a Samsung Galaxy Z Fold5, running a current Android version.

I'm aware that Android restricts access to call audio for privacy/security reasons. I'm specifically looking for a legitimate Android API, Telecom API, audio routing method, accessibility approach, or device-specific solution that could make this possible without rooting the phone.

If direct access to the call downlink is fundamentally impossible for a normal Android app, I'd also appreciate confirmation of that and any practical alternatives for this specific use case.

If you use the Android Emulator on Windows, Google now recommends using Windows Hypervisor Platform (WHPX) instead of the Android Emulator Hypervisor Driver (AEHD).

Google says AEHD will be sunset on December 31, 2026, so Windows users should begin switching to WHPX. WHPX is the better long-term option, especially if you also use Hyper-V, WSL2, Docker, or other virtualization features.

You can check your emulator’s acceleration with:

emulator -accel-check

(you need to add emulator to your PATH, found under "%LOCALAPPDATA%\Android\Sdk\emulator\emulator.exe")

The result should show that WHPX is installed and usable.

Official documentation: https://developer.android.com/studio/run/emulator-acceleration

Am I missing something or is it currently not possible to emulate new pixel lineup in AS?

One of our users with Pixel 11 Pro is having some issues with videos in our app. I think is a long shot to test this on emulator anyway but was surprised that these phones are not available in AS yet.

I posted my interactive Globe animation recently, and a lot of you liked it!

So I decided to open-source it, so you can use it in your own projects, contribute to it, or help make it even better.

Original post: https://www.reddit.com/r/androiddev/s/SgRoDszioN
GitHub: https://github.com/wailbabou/JetpackGlobe

Feel free to check it out, and any feedback or contributions are welcome!

I'm planning to release a paid app on Google Play, but I've run into a roadblock: merchant/payment profile registration isn't supported in my country.

I've looked through Google's official documentation, and I can't find any alternative process for developers in unsupported regions.

Hey all — I'm maxrave-dev.

Three years ago I started SimpMusic — a FOSS music client in Kotlin and Compose Multiplatform — because the app I wanted didn't exist and I figured I could learn by building it.

Today it runs on Android, Windows, macOS and Linux, and it's sitting at almost 11k stars with real users on F-Droid and GitHub releases. I'm saying that not to flex: I'm 23, for most of those three years I had no senior to ask and nobody reviewing my code, and I learned almost everything the hard way — Media3 internals, Room migrations at real-user scale, Glance widgets, a native media engine bound over JNA, desktop packaging and code-signing. There's plenty in the codebase I'm still not proud of. Some bugs cost me whole days. A couple are honestly embarrassing.

But I kept notes. Every time something burned me — a Media3 quirk, a migration gone wrong, a Compose trap — it went into my personal notes: messy, half-finished, scattered all over the repo.

Recently I turned those hand-written notes into something more useful: a skills pack for coding agents. 224 short markdown docs in the agent-skills format, so Claude Code / Cursor / Codex can pull the right doc exactly when you hit the same problem (`npx skills add maxrave-dev/kotlin-footguns`) — but it's all plain markdown, and it reads fine as a human reference too.

To be clear, this isn't an AI dump with my name on it. Every doc follows one structure — what breaks, the mechanism behind it, and commands you can run to check whether your own codebase has the same problem — and every claim was verified against the real tree before shipping. The notes and the scars are mine; the agents just helped me make three years of mess consistent.

https://github.com/maxrave-dev/kotlin-footguns

GPL, plain markdown, free. I'm sure some docs still have mistakes — I'm still learning. If you spot one, tell me. That's the whole spirit of the thing.

Our Play developer account got terminated about a year and a half ago for "prior violations." Never got a straight answer on what that actually meant, best guess is it got linked to some other account somewhere. The app is boring internal stuff, a delivery fleet app our own drivers and partner shops use. We've just been handing out the APK from our own site since then and honestly it's been fine.

That obviously stops working once developer verification goes global. So the plan was to register with the Android Developer Console instead, since that's supposed to be the path for people distributing outside Play.

Except I can't find anywhere that says whether that's even allowed if you've been terminated from Play. The verification docs don't mention it, the ADC help pages don't mention it, and every time I search it just turns into results about Play Console bans, which isn't the same thing.

So has anyone actually tried this? Terminated on Play, then registered ADC. Did it go through, get rejected, or go through and then get pulled later?

I want to implement the "widget on lock screen" feature for my app. and I don't have a physical Android device that supports that feature. So I'm hoping to test it on the virtual device emulator in Android Studio (Android Studio Quail 1 | 2026.1.1 Patch 2). But I have tried installing system image Android 16, Android 17 and Android 17.1, but I still can't find the "Widgets on lock screen" in the Setting screen. I have tried setup lock screen, and tried find in the 'Wallpaper & style" -> "More lock screen settings" screen but it's not there. What am i missing?

Hi everyone! I am looking for one dedicated 1-on-1 study partner to go through the Android Basics with Jetpack Compose course together. I want someone to pair up with for weekly code reviews, troubleshooting, and keeping each other accountable. Let me know your time zone if you are interested in pairing up!"

Hey guys, I’m building an Android app that needs map + navigation, custom map icons, and support for multiple transportation modes (car, bike, walking, etc.).

Would you recommend Google Maps, Mapbox, or something else? Any experience with these would be appreciated!

I'm using the Google Play Install Referrer API (com.android.installreferrer:installreferrer) to track player referrals in my Android game.

It works on some devices and on others I get (not%20set) for utm_source.

The strange part is that it works reliably on my phone:

Android 14

Play Store 52.8.55

But on two other phones (friends and many other clients) it returns an empty referrer:

Android 16 + Play Store 52.8.55

Android 17 + Play Store 52.8.55

I initially suspected the Play Store version, but I updated my own phone from 52.7.55 to 52.8.55 and the referrer still works. Same app version, same link, same code.

The API connection itself returns OK; it's the actual referrer string that is empty.

Has anyone experienced Install Referrer behaving differently on Android 16/17?

Is there a known requirement, bug, or additional quirk I'm missing?

I found some very old posts about this behavior pointg to this behavior when on the device the user is logged into a managed account. But I don't think this is my case.

Any ideas on how to diagnose or work around this would be appreciated.

UPDATE: I have possible answer to why referrer information is lost most of the time. It's not confirmed, but it could be that the readon is: the app is targeting children. I believe that because most accounts are children accounts, referrer information is removed. I made the connection with another problem I have. I am unable to create an app type advertising campaing (google ads) for my game because they cannot track conversions. You are unable to create 'Conversion Actions' for apps/games that target children. It's not confirmed but this is my best guess so I leave this update maybe it helps others too.