Add signing configuration and CI workflow

.github/workflows/gradle.yml

@@ -0,0 +1,42 @@
+name: Java CI with Gradle
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK 8
+      uses: actions/setup-java@v4
+      with:
+        java-version: '8'
+        distribution: 'temurin'
+
+    - name: Setup Android SDK
+      uses: android-actions/setup-android@v3
+      with:
+        cmdline-tools-version: 9123335
+
+    - name: Grant execute permission for Gradle wrapper
+      run: chmod +x ./gradlew
+
+    - name: Build with Gradle
+      run: ./gradlew assembleRelease
+
+    - name: Create release.tar.gz archive
+      run: tar -czvf release.tar.gz -C app/build/outputs/apk/release .
+
+    - name: Upload release.tar.gz
+      uses: actions/upload-artifact@v4
+      with:
+        name: release.tar.gz
+        path: ./release.tar.gz

app/build.gradle

@@ -26,8 +26,17 @@ android {
         versionCode 1
         versionName "0.1"
     }
+    signingConfigs {
+        release {
+            keyAlias 'my-key-alias'
+            keyPassword 'your-key-password'
+            storeFile file('my-release-key.jks')
+            storePassword 'your-keystore-password'
+        }
+    }
     buildTypes {
         release {
+            signingConfig signingConfigs.release
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }

generate-keystore.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias my-key-alias \
+-dname "CN=Your Name, OU=Your Organization, O=Your Company, L=Your City, ST=Your State, C=Your Country" \
+-storepass your-keystore-password -keypass your-key-password