Configure android gradle release build type

Author: ashtanko

android/app/build.gradle.kts

@@ -1,10 +1,20 @@
+import java.util.Properties
+import java.io.FileInputStream
+
 plugins {
     id("com.android.application")
     id("kotlin-android")
     // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
     id("dev.flutter.flutter-gradle-plugin")
 }
 
+val keystorePropertiesFile = rootProject.file("key.properties")
+val keystoreProperties = Properties().apply {
+    if (keystorePropertiesFile.exists()) {
+        load(FileInputStream(keystorePropertiesFile))
+    }
+}
+
 android {
     namespace = "dev.shtanko.flutter_bloc_app_template"
     compileSdk = flutter.compileSdkVersion
@@ -59,11 +69,27 @@ android {
         }
     }
 
+    signingConfigs {
+        register("release") {
+            enableV1Signing = true
+            enableV2Signing = true
+
+            storeFile = keystoreProperties["storeFile"]?.let { file(it) }
+            storePassword = keystoreProperties["storePassword"] as String?
+            keyAlias = keystoreProperties["keyAlias"] as String?
+            keyPassword = keystoreProperties["keyPassword"] as String?
+        }
+    }
+
     buildTypes {
         release {
-            // TODO: Add your own signing config for the release build.
-            // Signing with the debug keys for now, so `flutter run --release` works.
-            signingConfig = signingConfigs.getByName("debug")
+            isMinifyEnabled = true
+            isShrinkResources = true
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+            signingConfig = signingConfigs.getByName("release")
         }
     }
 }