android-studio: improve wrapper

pkgs/applications/editors/android-studio/common.nix

@@ -222,10 +222,35 @@ let
     in ''
       #!${runtimeShell}
       ${lib.optionalString hasAndroidSdk ''
-        # Default ANDROID_SDK_ROOT to the packaged one.
-        export ANDROID_SDK_ROOT="''${ANDROID_SDK_ROOT-${androidSdkRoot}}"
-        export ANDROID_HOME="$ANDROID_SDK_ROOT"
-        echo "Android Studio wrapper started with ANDROID_SDK_ROOT=$ANDROID_SDK_ROOT" >&2
+        echo "=== nixpkgs Android Studio wrapper ===" >&2
+
+        # Default ANDROID_SDK_ROOT to the packaged one, if not provided.
+        ANDROID_SDK_ROOT="''${ANDROID_SDK_ROOT-${androidSdkRoot}}"
+
+        if [ -d "$ANDROID_SDK_ROOT" ]; then
+          export ANDROID_SDK_ROOT
+
+          # Legacy compatibility.
+          export ANDROID_HOME="$ANDROID_SDK_ROOT"
+
+          echo "  - ANDROID_SDK_ROOT=$ANDROID_SDK_ROOT" >&2
+
+          # See if we can export ANDROID_NDK_ROOT too.
+          ANDROID_NDK_ROOT="$ANDROID_SDK_ROOT/ndk-bundle"
+          if [ ! -d "$ANDROID_NDK_ROOT" ]; then
+            ANDROID_NDK_ROOT="$(ls "$ANDROID_SDK_ROOT/ndk/"* 2>/dev/null | head -n1)"
+          fi
+
+          if [ -d "$ANDROID_NDK_ROOT" ]; then
+            export ANDROID_NDK_ROOT
+            echo "  - ANDROID_NDK_ROOT=$ANDROID_NDK_ROOT" >&2
+          else
+            unset ANDROID_NDK_ROOT
+          fi
+        else
+          unset ANDROID_SDK_ROOT
+          unset ANDROID_HOME
+        fi
       ''}
       exec ${fhsEnv}/bin/${drvName}-fhs-env ${androidStudio}/bin/studio.sh "$@"
     '';