From 605d88a37d0aba9aa2963de2b3298726ba9a9a02 Mon Sep 17 00:00:00 2001
From: Andrew Quan <AndrewQ@redblueprint.com>
Date: Fri, 26 Mar 2021 13:38:21 +0200
Subject: [PATCH] Android - Optimization

- added options for optimization:

```
"Android": {
"Optimize": {
"MinifyEnabled": true,
"ShrinkResources": true,
"DefaultAndroidProGuard": "proguard-android-optimize.txt",
"PrependRulesFile": "proguard-rules-prepend.pro",
"AppendRulesFile": "proguard-rules-append.pro"
},
...
```

Default android proguard rules(proguard-android.txt) are applied when not specified
```
"Android": {
"Optimize": {
"MinifyEnabled": true,
"ShrinkResources": true
},
...
```

Can add custom proguard rules before or after the main generated class rules:
```
"Android": {
"Optimize": {
"MinifyEnabled": true,
"ShrinkResources": true,
"PrependRulesFile": "proguard-rules-prepend.pro",
"AppendRulesFile": "proguard-rules-append.pro"
},
...
```

Create "proguard-rules-prepend.pro" in root of Project folder:

e.g.

MyApp/MainView.ux
MyApp/proguard-rules-prepend.pro

...

proguard-rules-prepend.pro
```
-keepattributes *Annotation*
-keepattributes Exceptions
-keepattributes InnerClasses
-keepattributes Signature
-keepattributes SourceFile,LineNumberTable
```
---
 lib/UnoCore/Targets/Android/Android.uxl      |  3 ++
 lib/UnoCore/Targets/Android/app/build.gradle | 44 ++++++++++++++++++--
 src/tool/engine/Targets/AndroidBuild.cs      | 11 +++++
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/lib/UnoCore/Targets/Android/Android.uxl b/lib/UnoCore/Targets/Android/Android.uxl
index 8175ee140..ff0a3dbc0 100644
--- a/lib/UnoCore/Targets/Android/Android.uxl
+++ b/lib/UnoCore/Targets/Android/Android.uxl
@@ -79,6 +79,9 @@
     <Set Outputs.AAR="app/build/outputs/aar/app-@(Build.Configuration:ToLower).aar" />
     <Set Outputs.APK="app/build/outputs/apk/@(Build.Configuration:ToLower)/app-@(Build.Configuration:ToLower).apk" />
     <Set Outputs.Bundle="app/build/outputs/bundle/@(Build.Configuration:ToLower)/app-@(Build.Configuration:ToLower).aab" />
+    
+    <Set ProGuard.PrependRulesFile="@(Project.Android.Optimize.PrependRulesFile:ToLower)" />
+    <Set ProGuard.AppendRulesFile="@(Project.Android.Optimize.AppendRulesFile:ToLower)" />
 
     <!-- Run-time properties -->
 
diff --git a/lib/UnoCore/Targets/Android/app/build.gradle b/lib/UnoCore/Targets/Android/app/build.gradle
index e90dd465f..44db897c2 100644
--- a/lib/UnoCore/Targets/Android/app/build.gradle
+++ b/lib/UnoCore/Targets/Android/app/build.gradle
@@ -51,7 +51,15 @@ android {
         targetSdkVersion @(SDK.TargetVersion)
         versionCode = @(Project.Android.VersionCode)
         versionName = '@(Project.Android.VersionName)'
-        multiDexEnabled @(Project.Android.MultiDexEnabled:IsSet:Test(@(Project.Android.MultiDexEnabled:Bool),true))
+
+ #if @(Project.Android.Optimize.MinifyEnabled:Test(1, 0))
+         //minifier handles multi-dexing for release
+         #if @(DEBUG:Defined)
+             multiDexEnabled @(Project.Android.MultiDexEnabled:IsSet:Test(@(Project.Android.MultiDexEnabled:Bool),true))
+         #endif
+ #else
+         multiDexEnabled @(Project.Android.MultiDexEnabled:IsSet:Test(@(Project.Android.MultiDexEnabled:Bool),true))
+ #endif
 
         ndk {
 #if @(DEBUG:Defined)
@@ -83,6 +91,12 @@ android {
 
     }
 
+    //prevent gradle build crash - https://stackoverflow.com/a/47689687/2139770
+    dexOptions {
+        javaMaxHeapSize "4g"
+    } 
+
+
 #if @(Project.Android.Bundle.Language.EnableSplit:IsSet) || @(Project.Android.Bundle.Density.EnableSplit:IsSet) || @(Project.Android.Bundle.ABI.EnableSplit:IsSet)
     bundle {
         #if @(Project.Android.Bundle.Language.EnableSplit:IsSet)
@@ -133,8 +147,32 @@ android {
 #elif @(Project.Android.Key.Store:IsSet)
             signingConfig = signingConfigs.release
 #endif
-            minifyEnabled = false
-            proguardFiles 'proguard-rules.pro'
+
+#if @(Project.Android.Optimize.MinifyEnabled:IsSet)
+            // Enables code shrinking, obfuscation, and optimization for only
+            // your project's release build type.
+            minifyEnabled @(Project.Android.Optimize.MinifyEnabled:ToLower)
+#else
+            minifyEnabled true
+#endif
+
+#if @(Project.Android.Optimize.ShrinkResources:IsSet)
+            // Enables resource shrinking, which is performed by the
+            // Android Gradle plugin.
+            shrinkResources @(Project.Android.Optimize.ShrinkResources:ToLower)
+#else
+            shrinkResources true
+#endif
+            // Includes the default ProGuard rules files that are packaged with
+            // the Android Gradle plugin. To learn more, go to the section about
+            // R8 configuration files.
+            proguardFiles getDefaultProguardFile(
+#if @(Project.Android.Optimize.DefaultAndroidProGuard:IsSet)
+                    '@(Project.Android.Optimize.DefaultAndroidProGuard:ToLower)'
+#else
+                    'proguard-android.txt'
+#endif
+            ), 'proguard-rules.pro'
         }
     }
 
diff --git a/src/tool/engine/Targets/AndroidBuild.cs b/src/tool/engine/Targets/AndroidBuild.cs
index 196344fb9..561ca5a69 100644
--- a/src/tool/engine/Targets/AndroidBuild.cs
+++ b/src/tool/engine/Targets/AndroidBuild.cs
@@ -52,9 +52,20 @@ public override void DeleteOutdated(Disk disk, IEnvironment env)
             var lines = new List<string> {"## This file was generated by Uno compiler."};
             var src = env.GetOutputPath("Java.SourceDirectory");
 
+            // Prepend user-defined proguard rules.
+             var proGuardPrependFile = env.GetString("ProGuard.PrependRulesFile");
+             if (proGuardPrependFile.IsValidPath())
+                 lines.AddRange(File.ReadAllLines(proGuardPrependFile));
+
+            // Add existing Java classes.
             if (Directory.Exists(src))
                 VisitSourceDirectoryRecursive(src, src, lines);
 
+             // Append user-defined proguard rules.
+             var proGuardAppendFile = env.GetString("ProGuard.AppendRulesFile");
+             if (proGuardAppendFile.IsValidPath())
+                 lines.AddRange(File.ReadAllLines(proGuardAppendFile));
+
             // End with newline.
             lines.Add("");