TV Clock — always-on overlay for Android TV / Google TV

A tiny Android TV app that pins the current time to the top-right corner of the screen, on top of every other app — launcher, YouTube, Netflix, anything. Built for personal use on a real TV (sideloaded, not a Play Store app).

⬇️ Download the APK  ·  📖 Illustrated explainer

Verified on a Google TV emulator: the 9:41-style clock renders over the launcher's content rows.

How it works

A normal app can only draw inside its own window, so it vanishes the moment you switch apps. The only way to float over everything is a system overlay window: the app hands a TextView to the WindowManager as TYPE_APPLICATION_OVERLAY, pinned TOP | END, refreshed every second. It's owned by a foreground service (not an Activity) so it survives app-switching, plus a BootReceiver restarts it after the TV reboots.

File	Role
MainActivity.kt	Launcher tile — checks the overlay permission and starts the service.
ClockOverlayService.kt	Foreground service that adds the clock to the WindowManager and ticks every second.
BootReceiver.kt	Restarts the overlay on BOOT_COMPLETED.

Written in Kotlin, zero third-party dependencies. Android TV / Google TV run the same runtime as phones, so there's no Java-only restriction.

• Stack: Kotlin 1.9.24 · AGP 8.7.2 · Gradle 8.9 · JDK 21
• SDK: minSdk 21 · targetSdk 33 · compileSdk 34

Build

Requires JDK 17–21 (the Android Gradle Plugin does not support JDK 23+) and the Android SDK. Point Gradle at your SDK via ANDROID_HOME or a local.properties file with sdk.dir=/path/to/Android/sdk.

JAVA_HOME=/path/to/jdk-21 ./gradlew assembleDebug
# → app/build/outputs/apk/debug/app-debug.apk

Install on your TV

Enable Developer options → USB/Network debugging on the TV, then:

./deploy.sh 192.168.1.50    # your TV's IP — connect + install + grant + launch

Or manually:

adb connect 192.168.1.50:5555
adb install -r app/build/outputs/apk/debug/app-debug.apk
adb shell appops set com.tatav.tvclock SYSTEM_ALERT_WINDOW allow   # the key step
adb shell am start -n com.tatav.tvclock/.MainActivity

Why the appops command? Android TV usually has no on-screen setting for "Draw over other apps", so the normal permission dialog never appears. Granting SYSTEM_ALERT_WINDOW over ADB is the reliable way. Without it, the app runs but shows no clock.

Try it on an emulator

echo no | $ANDROID_HOME/cmdline-tools/latest/bin/avdmanager create avd \
  -n tv_clock -k "system-images;android-34;android-tv;arm64-v8a" -d tv_1080p
$ANDROID_HOME/emulator/emulator -avd tv_clock -gpu auto &
./deploy.sh

Customize

All in app/src/main/java/com/tatav/tvclock/ClockOverlayService.kt:

• 24-hour time: change the format "h:mm a" → "HH:mm".
• Position / size / colour: tweak params.x/y, setTextSize, setBackgroundColor.

Notes

• DRM video: some streaming apps mark their surface "secure"; the system may hide all overlays during protected playback, so the clock can briefly disappear there. Everywhere else it stays.
• Debug-signed sideload for personal use — not intended for the Play Store.

Download

Grab the ready-to-sideload APK from the latest release, or read the full illustrated walkthrough at the live explainer (also in this repo as EXPLAINER.html).

License

MIT — see LICENSE.

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