Wires the workspace through `cargo apk build`. After this commit
`cargo apk build -p solitaire_app --target x86_64-linux-android`
produces a debug-signed APK at `target/debug/apk/solitaire-quest.apk`
containing all assets and `lib/x86_64/libsolitaire_app.so` — runnable
on the AVD or a physical x86_64 device.
The five gating points discovered by iterating compile cycles:
1. solitaire_app split into bin + lib. cargo-apk needs a `cdylib`
to bundle as `libmain.so`; pure-bin crates panic with
"Bin is not compatible with Cdylib". `src/lib.rs` carries the
ECS bootstrap as `pub fn run`; `src/main.rs` is a 3-line shim
that delegates for the desktop `cargo run` path.
2. `[package.metadata.android]` pins target SDK 34 / min SDK 26
so cargo-apk doesn't probe for whatever default it ships
(which on this machine was an uninstalled API 30). `assets =
"../assets"` lets the same asset directory feed both desktop
and APK.
3. Workspace `bevy` features add `android-native-activity` (the
Bevy-side glue that pairs with cargo-apk's NativeActivity
wrapper). The feature is target-gated inside bevy_internal so
desktop builds compile it out.
4. `arboard` (clipboard, used by Stats's "Copy share link") has
no Android backend — `cargo apk build` fails with E0433 on
`platform::Clipboard` if unconditional. Target-gated to
`cfg(not(target_os = "android"))`; the system surfaces an
informational toast on Android until JNI ClipboardManager is
wired in the Phase-Android round.
5. `keyring` + `keyring-core` cannot compile for android — the
transitive `rpassword` uses `libc::__errno_location` which
bionic doesn't expose. Both crates target-gated; `auth_tokens`
ships a stub on Android that returns `KeychainUnavailable` for
every call, matching how callers already handle a Linux box
without Secret Service.
Cosmetic post-pass panic: cargo-apk panics AFTER the APK is signed
when it tries to also wrap the bin target. The APK on disk is
unaffected. Working around this with `cargo apk build --lib` is
the next small step.
What's verified:
- Desktop `cargo build`, `cargo clippy --workspace --all-targets`,
and `cargo test --workspace` all clean.
- `cargo apk build -p solitaire_app --target x86_64-linux-android`
produces 54 MB debug APK with libsolitaire_app.so + assets.
What's NOT yet verified:
- Whether the APK actually launches on the AVD / a phone (next
step: `adb install` + `adb logcat` against the bevy_test AVD).
- Whether `dirs::data_dir()` on Android returns a usable path
(sync / persistence will surface this if not).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
funman300