Add proper proguard rules (#412)

* add proper proguard-rules

* enable apk optimisations

* Android: Remove duplicate proguard rule

* derp

---------

Co-authored-by: wheremyfoodat <44909372+wheremyfoodat@users.noreply.github.com>

src/pandroid/app/build.gradle.kts

@@ -22,8 +22,8 @@ android {
 
     buildTypes {
         getByName("release") {
-            isMinifyEnabled = false
-            isShrinkResources = false
+            isMinifyEnabled = true
+            isShrinkResources = true
             isDebuggable = false
             signingConfig = signingConfigs.getByName("debug")
             proguardFiles(

src/pandroid/app/proguard-rules.pro

@@ -1,16 +1,19 @@
-# Add project specific ProGuard rules here.
-# You can control the set of applied configuration files using the
-# proguardFiles setting in build.gradle.
-#
+# Pandroid Proguard Rules
 # For more details, see
 #   http://developer.android.com/guide/developing/tools/proguard.html
 
-# If your project uses WebView with JS, uncomment the following
-# and specify the fully qualified class name to the JavaScript interface
-# class:
-#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
-#   public *;
-#}
+# Keep all JNI and C++ related classes and methods
+-keepclasseswithmembernames class * {
+    native <methods>;
+}
+
+# Keep all native libraries and their methods
+-keep class * {
+    native <methods>;
+}
+
+# Keep all classes in the specified package and its subpackages
+-keep class com.panda3ds.pandroid.** {*;}
 
 # Uncomment this to preserve the line number information for
 # debugging stack traces.