Add tagged release flow with real APK signing

.github/workflows/android-release.yml

@@ -0,0 +1,75 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: Build and publish release APK
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '17'
+          cache: gradle
+
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Make Gradle wrapper executable
+        run: chmod +x ./gradlew
+
+      - name: Decode release keystore
+        env:
+          RELEASE_KEYSTORE_BASE64: ${{ secrets.RELEASE_KEYSTORE_BASE64 }}
+        run: |
+          set -euo pipefail
+          if [ -n "${RELEASE_KEYSTORE_BASE64:-}" ]; then
+            echo "$RELEASE_KEYSTORE_BASE64" | base64 -d > "$RUNNER_TEMP/release.keystore"
+            echo "RELEASE_KEYSTORE_PATH=$RUNNER_TEMP/release.keystore" >> "$GITHUB_ENV"
+          else
+            echo "::warning::RELEASE_KEYSTORE_BASE64 secret not set; release APK will be debug-signed."
+          fi
+
+      - name: Build release APK
+        env:
+          RELEASE_KEYSTORE_PASSWORD: ${{ secrets.RELEASE_KEYSTORE_PASSWORD }}
+          RELEASE_KEY_ALIAS: ${{ secrets.RELEASE_KEY_ALIAS }}
+          RELEASE_KEY_PASSWORD: ${{ secrets.RELEASE_KEY_PASSWORD }}
+        run: ./gradlew :app:assembleRelease --stacktrace
+
+      - name: Prepare release APK
+        run: |
+          set -euo pipefail
+          mkdir -p dist
+          APK_PATH="$(find app/build/outputs/apk/release -name '*.apk' | head -n 1)"
+          cp "$APK_PATH" "dist/Sploot-${GITHUB_REF_NAME}.apk"
+
+      - name: Upload release APK artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Sploot-release-apk
+          path: dist/Sploot-${{ github.ref_name }}.apk
+          if-no-files-found: error
+
+      - name: Create GitHub release
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          gh release create "${GITHUB_REF_NAME}" "dist/Sploot-${GITHUB_REF_NAME}.apk" \
+            --title "Sploot ${GITHUB_REF_NAME}" \
+            --generate-notes

app/build.gradle.kts

@@ -19,13 +19,29 @@ android {
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
 
+    val releaseKeystorePath = System.getenv("RELEASE_KEYSTORE_PATH")
+    signingConfigs {
+        if (releaseKeystorePath != null) {
+            create("release") {
+                storeFile = file(releaseKeystorePath)
+                storePassword = System.getenv("RELEASE_KEYSTORE_PASSWORD")
+                keyAlias = System.getenv("RELEASE_KEY_ALIAS")
+                keyPassword = System.getenv("RELEASE_KEY_PASSWORD")
+            }
+        }
+    }
+
     buildTypes {
         release {
             isMinifyEnabled = true
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
             )
+            // Falls back to debug signing for local builds where the release
+            // keystore env vars aren't set, e.g. outside of the release CI job.
+            signingConfig = signingConfigs.findByName("release")
+                ?: signingConfigs.getByName("debug")
         }
     }