Allow to build without signing

Author: eikek

app/build.gradle

@@ -14,36 +14,38 @@ android {
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
-    buildTypes {
-        release {
-            minifyEnabled false
-            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
-        }
-    }
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
     signingConfigs {
         release {
-            storeFile file(RELEASE_STORE_FILE)
-            storePassword RELEASE_STORE_PASSWORD
-            keyAlias RELEASE_KEY_ALIAS
-            keyPassword RELEASE_KEY_PASSWORD
-
             // Optional, specify signing versions used
             v1SigningEnabled true
             v2SigningEnabled true
         }
     }
-
     buildTypes {
         release {
             signingConfig signingConfigs.release
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
 }
 
+if (project.hasProperty('KEYSTORE_FILE') &&
+    project.hasProperty('KEYSTORE_PASSWORD') &&
+    project.hasProperty('KEY_ALIAS') &&
+    project.hasProperty('KEY_PASSWORD')) {
+    android.signingConfigs.release.storeFile = file(KEYSTORE_FILE)
+    android.signingConfigs.release.storePassword = KEYSTORE_PASSWORD
+    android.signingConfigs.release.keyAlias = KEY_ALIAS
+    android.signingConfigs.release.keyPassword = KEY_PASSWORD
+} else {
+    android.buildTypes.release.signingConfig = null
+}
+
 dependencies {
     coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:1.0.10'