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Windows Disposable Emulator Workflow (Phone + Wear OS)

Use this when Android native builds fail in your normal workspace because of long Windows paths.

This guide runs everything from a disposable copy at C:\e, then removes it at the end.

Prerequisites

  • Android Studio with:
    • Android Emulator
    • A phone AVD
    • A Wear OS AVD
  • Node + pnpm available in PowerShell
  • Source repo available at C:\dev\apps\eclipse-timer

0) Add more emulator profiles (phone and Wear)

Use Android Studio Device Manager to create more virtual devices.

  1. Open Android Studio.
  2. Go to Tools -> Device Manager.
  3. Click + -> Create Virtual Device.

Wear examples

  • In Device Manager, switch to the Wear OS tab when choosing hardware.
  • Good options:
    • Pixel Watch family profiles
    • Pixel Watch 2 or Pixel Watch 3 if available in your Android Studio version
  • Choose a Google APIs system image (x86_64), preferably a recent API level.
  • Name the AVD clearly, for example:
    • Wear_Pixel_Watch_3_API_35

Phone examples

  • In Device Manager, use a standard phone profile (for example Pixel 8 Pro) or create a custom profile.
  • For a Samsung Galaxy S25 Ultra-like test device, create a custom hardware profile with approximate specs:
    • Name: Galaxy_S25_Ultra_Approx_API_36
    • Screen size: 6.9"
    • Resolution: 1440 x 3120
    • RAM/Storage: use practical emulator values supported by your machine
  • Then pick a Google APIs system image and finish creation.

Notes:

  • Stock Android Emulator does not emulate Samsung One UI behavior exactly.
  • Use a real Samsung device for vendor-specific UI behavior and OEM features.
  • You can list all created AVDs with:
$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$emu="$env:ANDROID_SDK_ROOT\emulator\emulator.exe"
& $emu -list-avds

1) Create a disposable copy at C:\e

Run in PowerShell:

$src = "C:\dev\apps\eclipse-timer"
$dst = "C:\e"

if (Test-Path $dst) {
  Remove-Item $dst -Recurse -Force
}

New-Item -ItemType Directory -Path $dst | Out-Null

# Copy working files but skip heavy/generated folders.
robocopy $src $dst /E `
  /XD .git node_modules apps\mobile\android\build apps\mobile\android\.cxx apps\mobile\.expo

# Robocopy uses non-zero success codes. 0-7 are success.
if ($LASTEXITCODE -gt 7) {
  throw "robocopy failed with exit code $LASTEXITCODE"
}

2) Install dependencies in the disposable copy

Set-Location C:\e

# Avoid deeply nested pnpm paths on Windows native Android builds.
"node-linker=hoisted" | Set-Content .npmrc

pnpm install --force

3) Start phone emulator (Terminal A)

$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$emu="$env:ANDROID_SDK_ROOT\emulator\emulator.exe"

& $emu -list-avds
& $emu -avd "Medium_Phone_API_36.1" -no-snapshot-load

Replace the sample AVD name with your exact name from -list-avds.

Keep this terminal open while the emulator runs.

4) Start Wear emulator (Terminal B)

$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$emu="$env:ANDROID_SDK_ROOT\emulator\emulator.exe"

& $emu -list-avds
& $emu -avd "Wear_OS_XL_Round" -no-snapshot-load

Replace the sample AVD name with your exact name from -list-avds.

Keep this terminal open while the emulator runs.

5) Capture emulator serials (Terminal C)

$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$adb="$env:ANDROID_SDK_ROOT\platform-tools\adb.exe"

& $adb devices -l

Set variables from the output, for example:

$phone = "emulator-5554"
$watch = "emulator-5556"

6) Build and run phone app from C:\e (Terminal C)

Set-Location C:\e

# Clear mismatched signatures if needed.
& $adb -s $phone uninstall com.lallimaven.eclipsetimer 2>$null

pnpm -C apps/mobile android

pnpm -C apps/mobile android stays running because Metro stays attached. That is expected.

7) Build and install Wear app (Terminal D)

$phone = "emulator-5554"
$watch = "emulator-5556"
$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$adb="$env:ANDROID_SDK_ROOT\platform-tools\adb.exe"

Set-Location C:\e\apps\mobile\android
.\gradlew.bat :wear:assembleDebug

# Clear mismatched signatures if needed.
& $adb -s $watch uninstall com.lallimaven.eclipsetimer 2>$null

& $adb -s $watch install -r wear\build\outputs\apk\debug\wear-debug.apk
& $adb -s $watch shell am start -n com.lallimaven.eclipsetimer/com.lallimaven.eclipsetimer.wear.MainActivity

8) Pair phone and watch emulators in Android Studio

Use Android Studio's Wear OS pairing assistant.

  1. Ensure both emulators are running and fully booted.
  2. Open Android Studio -> Tools -> Device Manager.
  3. On either device row (phone or watch), click the overflow menu (...) and choose Pair Wearable.
  4. In the pairing assistant, select the matching device and click Next.
  5. Wait while Android Studio prepares both emulators.
  6. If prompted on the phone emulator, install/open the Wear OS by Google app from Play Store and complete setup prompts.
  7. In the phone's Wear OS app, open the overflow menu and tap Pair with emulator.
  8. Accept pairing/association prompts that appear on phone/watch.
  9. Confirm pairing succeeded:
    • Device Manager shows paired-device indicators.
    • The watch and phone remain listed as paired after relaunch.

Recommended AVD compatibility for pairing assistant:

  • Phone emulator: Android 11 (API 30) or newer, with Google Play image.
  • Wear emulator: API 28 or newer.

9) Optional phone-watch bridge check

Reopen the watch app and verify status progresses from waiting text to a phone reply.

Troubleshooting: pnpm -C apps/mobile android installs to Wear

If both phone and watch emulators are running, Expo may choose the wrong device unless you specify one.

Use explicit device targeting for the phone app:

$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$adb="$env:ANDROID_SDK_ROOT\platform-tools\adb.exe"

& $adb devices -l
# Example phone serial:
$phone = "emulator-5554"

pnpm -C apps/mobile android -- --device $phone

If ANDROID_SERIAL is set to a watch serial, clear it:

Remove-Item Env:ANDROID_SERIAL -ErrorAction SilentlyContinue

If you want to force phone targeting for the current terminal session:

$env:ANDROID_SERIAL = "emulator-5554"
pnpm -C apps/mobile android

Use this only for phone app runs. Clear/reset it before running watch-specific adb -s <watch-serial> ... commands.

Troubleshooting: react-native-screens:configureCMakeDebug[...] fails with missing prefab_command.bat

If the error shows a CreateProcess error=2 with a stale path under C:\dev\apps\eclipse-timer\..., your disposable copy at C:\e is using an outdated React Native autolinking cache.

Regenerate autolinking from C:\e:

Set-Location C:\e\apps\mobile\android
cmd /c del /f /q build\generated\autolinking\autolinking.json
.\gradlew.bat :app:generateAutolinkingPackageList
pnpm -C C:\e\apps\mobile android

If it still fails once, clear build outputs and retry:

cmd /c rmdir /s /q C:\e\apps\mobile\android\build
cmd /c rmdir /s /q C:\e\node_modules\react-native-screens\android\build
pnpm -C C:\e\apps\mobile android

10) Cleanup and remove C:\e

After testing:

$env:ANDROID_SDK_ROOT="$env:LOCALAPPDATA\Android\Sdk"
$adb="$env:ANDROID_SDK_ROOT\platform-tools\adb.exe"

# Stop Metro/Expo terminal first (Ctrl+C), then stop emulators.
& $adb -s $phone emu kill
& $adb -s $watch emu kill

Set-Location C:\dev\apps\eclipse-timer
Remove-Item C:\e -Recurse -Force

Any edits made inside C:\e are discarded by design.