feat(poc/audio): add Android mobile audio spike

Closes the mobile half of the PoC plan §2 audio exit criterion left open by poc/audio-capture-playback-spike. The desktop and mobile halves together fully retire the audio PoC. Stack: Kotlin (MainActivity) → JNI → Rust cdylib → cpal 0.16 → Oboe (AAudio / OpenSL ES) → Android audio HAL Layout: rust crate (src/lib.rs) — JNI_OnLoad, initContext, playSine440, record1sToFile; panic-catching at JNI boundary; android_logger → logcat android/ (Gradle 8.7, — minSdk 24, compileSdk 34, AGP 8.5.2. AGP 8.5.2, Kotlin 1.9.24) cargoBuildRust task wraps cargo-ndk -P 26 -t <abi> for all four ABIs; wired into preBuild so AGP picks up the produced .so files. Verified on 2026-05-13 on a physical Motorola Moto G Stylus 5G (2023), Android 14 SDK 34 arm64-v8a: - Playback: 500 ms 440 Hz mono sine, 22,050 frames emitted at 44.1 kHz through cpal/Oboe/AAudio/device speaker. - Capture: 1 s from default input, 42,624 frames written to /data/data/app.chanora.poc.audio/files/chanora_poc_capture.wav. File pulled via 'adb exec-out run-as ... cat' and confirmed by file(1) as 'RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 44100 Hz'. Header bytes cross-checked against the reported frame count. Notes: - cpal links libaaudio (introduced API 26), so cargo-ndk targets API 26 via -P 26 while the Android module's minSdk stays at 24 (DEC-004). API 24/25 devices would fall back to OpenSL ES at runtime; not exercised here. - JNI panic safety: every JNI entry point wraps its body in std::panic::catch_unwind and a tracing panic hook routes panic messages to logcat under tag 'ChanoraAudioPoC'. Without this, cpal panicking inside an extern "system" function would abort the process. - The emulator AVD chanora-poc-api34 and its system image were installed during Phase 0 but emulator verification was skipped once the physical-device run succeeded. Real-device evidence is stronger. Surfaced finding: DEC-011.1 mobile half promoted from Deferred to Accepted for Android in the same docs commit; iOS remains explicitly Deferred (requires macOS + Xcode hardware). Authority: PoC plan §2, DEC-011, DEC-011.1. Not product code; not promoted into chanora_audio.
2026-05-14 18:24:53 +08:00
parent eca93a141e
commit ec21a880d2
15 changed files with 2278 additions and 0 deletions
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- Required for capture. Cpal's Oboe input stream needs this. -->
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+
+    <application
+        android:label="Chanora Audio PoC"
+        android:allowBackup="false"
+        android:supportsRtl="true"
+        android:theme="@android:style/Theme.Material.Light">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>
@@ -0,0 +1,134 @@
+package app.chanora.poc.audio
+
+import android.Manifest
+import android.app.Activity
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.util.Log
+import android.view.View
+import android.widget.Button
+import android.widget.LinearLayout
+import android.widget.TextView
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
+import java.io.File
+import kotlin.concurrent.thread
+
+/**
+ * Chanora PoC — Android mobile audio spike.
+ *
+ * Two buttons:
+ *   1) Play 500 ms 440 Hz sine wave through the default output device.
+ *   2) Record 1 s from the default input device to app-private storage.
+ *
+ * Both call into the Rust cdylib via JNI. Status is logged to logcat
+ * under the tag "ChanoraAudioPoC" (Rust) and "ChanoraPoCActivity"
+ * (Kotlin). The UI also displays the result string.
+ */
+class MainActivity : Activity() {
+
+    private companion object {
+        const val TAG = "ChanoraPoCActivity"
+        const val REQ_RECORD = 1001
+    }
+
+    private lateinit var status: TextView
+    private lateinit var recordBtn: Button
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        // Hand the Application Context to the Rust side BEFORE any
+        // audio call, so cpal's Oboe backend can find Android audio
+        // services via ndk_context.
+        NativeAudio.initContext(applicationContext)
+
+        val root = LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            setPadding(48, 48, 48, 48)
+        }
+
+        val title = TextView(this).apply {
+            text = "Chanora Audio PoC (Android)"
+            textSize = 20f
+        }
+
+        status = TextView(this).apply {
+            text = "ready"
+            textSize = 14f
+            setPadding(0, 24, 0, 24)
+        }
+
+        val playBtn = Button(this).apply {
+            text = "Play 500 ms sine"
+            setOnClickListener { onPlay() }
+        }
+
+        recordBtn = Button(this).apply {
+            text = "Record 1 s to file"
+            setOnClickListener { onRecord() }
+        }
+
+        root.addView(title)
+        root.addView(status)
+        root.addView(playBtn)
+        root.addView(recordBtn)
+        setContentView(root)
+    }
+
+    private fun setStatus(s: String) {
+        Log.i(TAG, s)
+        runOnUiThread { status.text = s }
+    }
+
+    private fun onPlay() {
+        setStatus("playing…")
+        thread(name = "chanora-poc-play") {
+            val frames = NativeAudio.playSine440(500L)
+            if (frames < 0) {
+                setStatus("PLAY ERROR (see logcat)")
+            } else {
+                setStatus("PLAY OK frames=$frames")
+            }
+        }
+    }
+
+    private fun onRecord() {
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO)
+                != PackageManager.PERMISSION_GRANTED) {
+            ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.RECORD_AUDIO), REQ_RECORD)
+            setStatus("requesting RECORD_AUDIO…")
+            return
+        }
+        doRecord()
+    }
+
+    private fun doRecord() {
+        setStatus("recording 1 s…")
+        thread(name = "chanora-poc-record") {
+            val path = File(filesDir, "chanora_poc_capture.wav").absolutePath
+            val frames = NativeAudio.record1sToFile(path, 1000L)
+            if (frames < 0) {
+                setStatus("RECORD ERROR (see logcat)")
+            } else {
+                val sz = File(path).length()
+                setStatus("RECORD OK frames=$frames bytes=$sz path=$path")
+            }
+        }
+    }
+
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray
+    ) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        if (requestCode == REQ_RECORD) {
+            if (grantResults.firstOrNull() == PackageManager.PERMISSION_GRANTED) {
+                doRecord()
+            } else {
+                setStatus("RECORD_AUDIO permission denied")
+            }
+        }
+    }
+}
@@ -0,0 +1,22 @@
+package app.chanora.poc.audio
+
+import android.content.Context
+
+object NativeAudio {
+    init {
+        System.loadLibrary("audio_capture_playback_android_spike")
+    }
+
+    /**
+     * Must be called once after `System.loadLibrary` with the
+     * application Context. Initialises the Rust-side `ndk_context`
+     * that cpal/Oboe relies on to locate Android audio services.
+     */
+    external fun initContext(context: Context)
+
+    /** Returns the number of frames emitted, or -1 on error. */
+    external fun playSine440(durationMs: Long): Long
+
+    /** Returns the number of frames captured, or -1 on error. */
+    external fun record1sToFile(path: String, durationMs: Long): Long
+}