Refactor Android CI workflow to use Nix actions and improve translation file collection

.github/actions/nix-devshell/action.yml

@@ -0,0 +1,50 @@
+name: "nix-devshell"
+description:
+  "Set up Nix, prebuild the devshell and run commands inside the devshell."
+inputs:
+  prebuild:
+    description:
+      "Whether to prebuild the devshell (nix develop --command true)."
+    required: false
+    default: "false"
+  commands:
+    description:
+      "Commands to run inside the devshell (executed with bash -lc)."
+    required: false
+    default: ""
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install Nix (idempotent)
+      shell: bash
+      run: |
+        set -euo pipefail
+        if ! command -v nix >/dev/null 2>&1; then
+          curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
+        fi
+        # source the nix profile if present
+        if [ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]; then
+          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
+        fi
+        nix --version
+
+    - name: Prebuild devshell
+      if: ${{ inputs.prebuild == 'true' }}
+      shell: bash
+      run: |
+        set -euo pipefail
+        if [ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]; then
+          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
+        fi
+        nix --extra-experimental-features 'nix-command flakes' develop --command true
+
+    - name: Run commands in devshell
+      if: ${{ inputs.commands != '' }}
+      shell: bash
+      run: |
+        set -euo pipefail
+        if [ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]; then
+          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
+        fi
+        nix --extra-experimental-features 'nix-command flakes' develop --command bash -lc "${{ inputs.commands }}"

.github/workflows/android.yaml

@@ -11,28 +11,30 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Install Nix (for nix usage)
-        run: |
-          set -euo pipefail
-          curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
-          nix --version
-
       - name: Checkout code
         uses: actions/checkout@v6
 
+      - name: Prepare Nix devshell
+        uses: ./.github/actions/nix-devshell
+        with:
+          prebuild: "true"
+
       - name: Collect Translation Files
-        run: |
+        uses: ./.github/actions/nix-devshell
-          set -euo pipefail
+        with:
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
+          commands: |
-          nix --version
             cd lib/l10n
-          nix --extra-experimental-features 'nix-command flakes' develop --command python3 collect_translations.py
+            python3 collect_translations.py
-          cd ../..
 
       - name: Build Debug APK
-        run: |
+        uses: ./.github/actions/nix-devshell
-          set -euo pipefail
+        with:
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
+          commands: |
-          nix --version
+            flutter build apk --debug --target-platform android-arm64
-          nix --extra-experimental-features 'nix-command flakes' develop --command flutter build apk --debug
+
+      - name: Upload APK artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-debug-apk
+          path: build/app/outputs/flutter-apk/*.apk
+          # retention-days: 90