ElDavoo/ylih

Headphones die. Before they do, ylih answers the one question that matters: how many hours did you get out of them?

Every connect and disconnect gets a timestamp, automatically, forever, on your phone only.

• Lifetime hours for each pair. Retire a dead pair and its total freezes; the next pair of the same model starts at zero.
• Every session, kept for good — start, end, duration.
• Listening time, not just connected time (optional), so headphones worn around your neck don't count as listening.
• Cost per hour, if you tell it what you paid. It goes down every time you wear them.
• Hours per charge, if your headphones report battery — and how that's changed since new. A charge cycle is 100% of battery used, however many part-charges it took. Pairs that don't report battery to Android have no such section.
• The last thirty days as a chart, with every day listed underneath.
• Home-screen widgets — lifetime hours, today's total, or the thirty-day chart.

Most people never need to change this.

By default nothing of the app runs — a connection is two timestamps Android reports on its own. Wired headphones are the exception: Android only reports those to an app already awake, so detailed tracking keeps something running, and stays off unless you enable it in Settings.

The app has no internet permission — nothing uploaded, no accounts, no analytics, no ads.

Your history lives in a database on the phone. Settings → Export writes it out as a readable file; Import puts it back. Android's own backup carries years of history to a new phone — the system copies the file, not the app sending it. Uninstalling offers to keep the data.

Automatic backups write that same file into a folder you pick — daily, weekly or monthly — keeping the latest ten. The folder can be anywhere the system file picker reaches, a synced cloud folder included; ylih itself still sends nothing. If the folder goes away, a notification says so once rather than failing quietly for months.

Assistants, only if you ask. Android 17 lets an app offer read-only questions to an on-device assistant. ylih offers two — lifetime hours per pair, and today / 7-day / 30-day totals — shipped switched off: until you enable Settings → assistant access, the system doesn't list them. Neither can change or delete anything, and disabling the switch removes them from the system too, not just the app.

The full policy is in PRIVACY.md.

Both are the same app, built from this repository:

• F-Droid — built and verified by F-Droid.
• Obtainium or the Releases page — updates straight from here.
• Google Play — one difference: tracking wired headphones there also requires Bluetooth access, since Play's rules make it unavoidable. Everything else is identical.

The app speaks 77 languages and follows your system language.

Long-term totals are worthless if a crash or reboot adds twelve hours to them:

• Time your phone spent switched off is never counted.
• A session interrupted by a reboot or a crash closes at the last moment it was known connected, never guessed forward.
• The same connection is never counted twice.

Tests pin these rules and fail the build if any stop holding.

Kotlin, Jetpack Compose, Room and Glance widgets, built with Gradle. A nix dev shell pins the exact JDK, Gradle and Android SDK:

nix develop                        # or: direnv allow
./gradlew assembleClassicDebug     # sideload build
./gradlew installClassicDebug

Without nix: JDK 21, Android SDK platform android-37.0 and build-tools 37.0.0 — the Gradle wrapper does the rest. Two flavors exist, classic (F-Droid and GitHub) and play, so every task is flavor-qualified; there is no plain assembleDebug.

# what CI runs, per flavor
./gradlew lintClassicReleaseTest testClassicReleaseTestUnitTest \
          assembleClassicDebug assembleClassicRelease

Lint and the Kotlin compiler run with warnings as errors and no baseline, so a warning fails the build. The test suite is mostly Robolectric and gated on coverage in CI.

• CLAUDE.md — the architecture in depth: the write funnel and its invariants, device identity, the widgets, and the build-system constraints.
• docs/play-store.md — the Play release runbook.
• docs/fdroid.md — the F-Droid runbook; the build recipe is at metadata/it.eldavo.ylih.yml.

Store screenshots, the icon and the feature graphic are generated, not drawn — they render the real UI on the JVM, so they cannot drift from the shipped app:

./gradlew recordRoborazziClassicReleaseTest

MIT — see LICENSE.