iterating-on-voltius-android

Testing & Quality

Use when building, deploying, running, screenshotting, clicking through, or debugging the Voltius Tauri app on a real Android phone — drives the on-device debug APK through the tauri-android MCP (adb + Chrome DevTools Protocol) so changes are seen and interacted with on the device, not just compiled.

QUICK START

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Iterating on Voltius Android

Overview

Build the debug APK, install it on the phone, then look at it and drive it on the device through the tauri-android MCP (adb + CDP). Same tool names as the desktop tauri-docker backend, selected by PLATFORM=android. A cross-compile only proves ABI linkage — the Android sandbox (SELinux, no shell spawn, no raw devices, scoped storage) breaks several host-integration features at runtime; the only proof a feature works is driving it on the phone and reading the screenshot. See docs/android-dev.md (runbook) and docs/android-feature-gaps.md (triage queue).

Build (x86_64 WSL2 laptop — build here)

scripts/android-build.sh aarch64   # Docker (Dockerfile.android); native NDK on x86_64, no QEMU

Output: src-tauri/gen/android/app/build/outputs/apk/universal/debug/app-universal-debug.apk (~310 MB, debug-signed with committed keystore/voltius-debug.keystore → adb install -r upgrades). On an aarch64 host the NDK runs under QEMU (~1h clean) — avoid; build on the x86_64 box.

Reach the phone + deploy (do this FIRST — MCP is useless if adb can't see the phone)

Phone plugs into Windows; WSL reaches it via a Windows-hosted adb server. Full setup + the three non-obvious blockers (Hyper-V firewall, adb version match, RSA auth) live in the android-adb-wsl-setup memory. Quick check before anything else:

export ADB_SERVER_SOCKET=tcp:192.168.240.1:5037   # set inline EVERY Bash call (fresh shell each time)
timeout 3 bash -c 'echo > /dev/tcp/192.168.240.1/5037' && echo OPEN || echo "DROPPED — firewall"
adb devices                                        # want: <serial>  device  (not unauthorized/empty)
scripts/android-deploy.sh <apk>                    # install -r + am start com.voltius.app/.MainActivity
adb shell grep -a webview_devtools_remote /proc/net/unix   # want @webview_devtools_remote_<pid> = app up

Register the MCP (android mode)

claude mcp add tauri-android --scope user \
  --env PLATFORM=android --env ADB_SERVER_SOCKET=tcp:192.168.240.1:5037 \
  -- npx -y "github:VoltiusApp/mcp-tauri-automation#android-backend"

Mid-session gotcha: a freshly-added MCP's tools are NOT callable until the session reloads (tool registry is fixed at startup). Restart Claude Code, or /reload-plugins, then the mcp__tauri-android__* tools appear. claude mcp list shows connected ≠ tools loaded.

Drive loop

launch_app (appPath ignored) → starts activity, finds WebView socket, adb forwards it, attaches CDP. Confirm get_app_state → isRunning: true.
click_element / type_text / press_key / wait_for_element / get_element_text — CSS selectors only (no :contains/XPath); grep the component, don't guess. Same selector rules as iterating-on-voltius-ui.
capture_screenshot → full native frame via adb exec-out screencap → Read the file and look. Blank/old frame = launch failed.
execute_tauri_command → window.__TAURI__.core.invoke(...) to probe a backend command.

Native dialogs (permission prompts, system file picker) are OUTSIDE the WebView — CDP can't touch them. Drive with adb shell input tap <x> <y> / adb shell input keyevent <KEY> at coordinates read from a screenshot.

Root-causing a feature on device

Watch the Rust side while you drive: adb logcat -d -t 200 | grep -iE 'voltius|RustStdoutStderr|panic|FATAL'. A panic at startup with no WebView socket = a host-integration feature failed early (keychain, PTY, serial). Reproduce → logcat → root-cause → fix → re-deploy → re-drive. One branch + commit per feature gap (docs/android-feature-gaps.md).

Common mistakes

Mistake	Fix
Forgetting `ADB_SERVER_SOCKET` in a Bash call	Each call is a fresh shell — `export` it inline every time
`adb devices` hangs forever	Don't poll it raw; bounded `timeout 3 bash -c 'echo >/dev/tcp/<ip>/5037'` first; hang = firewall drop
MCP "connected" but tools missing	Tool registry fixed at startup — restart / `/reload-plugins` after adding the MCP
Driving a native dialog via CDP	Native UI is outside the WebView — `adb shell input tap/keyevent`
"It compiled / installed" = works	Cross-compile ≠ runtime; sandbox breaks host features. Drive it, read the screenshot, check logcat
Building on the aarch64 box	NDK runs under QEMU there (~1h) — build on the x86_64 WSL laptop
Regenerating the dev keystore	Breaks `install -r` upgrades — keystore is committed, never regenerate