some customizations to set up gradle with chaquopy

app/app/build.gradle

 plugins {
     id 'com.android.application'
     id 'org.jetbrains.kotlin.android'
+    id 'com.chaquo.python'
 }
 
 android {
@@ -14,6 +15,15 @@ android {
         versionName "1.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+        ndk {
+            abiFilters "armeabi-v7a", "arm64-v8a", "x86", "x86_64"
+        }
+
+        python {
+            version "3.9"
+	    buildPython "python3.9"
+        }
     }
 
     buildTypes {
@@ -45,4 +55,4 @@ dependencies {
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
-}
\ No newline at end of file
+}

app/app/src/main/python/main.py

+from kivy.app import App
+from kivy.uix.label import Label
+
+class MainApp(App):
+    def build(self):
+        label = Label(text='Hello from Kivy',
+                      size_hint=(.5, .5),
+                      pos_hint={'center_x': .5, 'center_y': .5})
+
+        return label
+
+if __name__ == '__main__':
+    app = MainApp()
+    app.run()

app/build.gradle

@@ -3,6 +3,7 @@ plugins {
     id 'com.android.application' version '7.2.1' apply false
     id 'com.android.library' version '7.2.1' apply false
     id 'org.jetbrains.kotlin.android' version '1.6.10' apply false
+    id 'com.chaquo.python' version '13.0.0' apply false
 }
 
 task clean(type: Delete) {

flake.nix

@@ -28,7 +28,9 @@
     };
   };
   outputs = { self, nixpkgs, flake-utils, mach-nix-flake, buildozerSrc, pythonForAndroidSrc, ... }:
-    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system: let
+    flake-utils.lib.eachSystem [
+      "x86_64-linux"
+    ] (system: let
 
       mach-nix = mach-nix-flake.lib.${system};
       pkgs = import nixpkgs {
@@ -68,10 +70,69 @@
       androidComposition = pkgs.callPackage ./android.nix { inherit cmakeVersion; };
 
       getBuildInputs = getInputs: xs: builtins.foldl' (accum: drv: (getInputs drv) ++ accum) [] xs;
+
+      chaquopy-env = mach-nix.mkPython {
+        python = "python39";
+        requirements = ''
+          chaquopy
+        '';
+      };
     in {
+
+      packages.default = pkgs.androidenv.buildApp {
+        name = "PrivateStorage Mobile";
+        src = ./app;
+        release = false;
+
+        platformVersions = [ "27" ];
+        includeNDK = false;
+      };
+
+      apps.emulator = {
+        type = "app";
+        program = let
+          emulator = pkgs.androidenv.emulateApp {
+            name = "PrivateStorage Mobile";
+            platformVersion = "27";
+            abiVersion = "x86_64";
+            systemImageType = "default";
+            app = ./app/app/build/outputs/apk/debug/app-debug.apk;
+            package = "MyApp";
+            activity = "MainActivity";
+          };
+        in
+          "${emulator}/bin/emulate-it???";
+      };
+      devShells.gradle = pkgs.mkShell rec {
+        name = "nix-native";
+        version = "2022.11.09";
+
+        ANDROIDSDK = "${androidComposition.androidsdk}/libexec/android-sdk";
+        ANDROIDNDK = "${ANDROIDSDK}/ndk-bundle";
+
+        buildInputs = with pkgs; [
+
+          # XXXX
+          # gradle finds an aapk2 from some random tgz it downloads from internet instead of from our ANDROIDSDK!  GREAT!!!!!!!!!!11111
+          #
+          # Fix the one it downloads, if it didn't already root you, with:
+          #
+          #  patchelf --set-interpreter <correct ld.so> ~/.gradle/<...path to aapt2>
+
+          gradle
+          ant
+          # openjdk8
+          android-studio
+          android-tools
+          python39
+        ];
+      };
+
+      devShells.default = self.devShells.${system}.gradle;
+
       # https://github.com/NixOS/nixpkgs/blob/master/doc/languages-frameworks/android.section.md
       # is a good reference for this stuff.
-      devShells.default = pkgs.mkShell rec {
+      devShells.kivy = pkgs.mkShell rec {
         name = "ps-mobile";
         version = "2022.10.21";
 
@@ -86,6 +147,7 @@
 
         buildInputs = with pkgs; [
           android-studio
+          android-tools
           kivy-env
 
           # Kivy and python-for-android depend on: