ndk-config-provider

Android Studio example how to provide configuration from assets (app/src/main/assets) or resources (app/src/main/res/raw) to Native (C/C++) code.

How it works

Assets

It performs via NDK Asset API

Raw Resorces

To access config file hosted in resorces from native code, you need to do some workarounds:

1. Copy the resource file to the local app storage.
2. Provide the path to stored file to native via JNI or via Environment Variable.

The following diagram shows this:

Expected logcat output

For "MainActivityJNI" tag:

Getting path to configuration folder via calling JNI method from Java (GET_PATH_VIA_ENV_VAR is not defined):

2021-04-20 12:39:41.115 26129-26129/com.example.myapp D/MainActivityJNI: asset_config.json:
    {
        "id": 1234,
        "name": "asset_config"
    }
2021-04-20 12:39:41.115 26129-26129/com.example.myapp D/MainActivityJNI: Get config path via JNI
2021-04-20 12:39:41.115 26129-26129/com.example.myapp D/MainActivityJNI: /data/user/0/com.example.myapp/files/res_raw_config.json:
    {
        "id": 5678,
        "name": "res_raw_config"
    }

Getting path to configuration folder via setting-getting Environment Variable (GET_PATH_VIA_ENV_VAR is defined):

2021-04-20 12:41:24.515 26278-26278/com.example.myapp D/MainActivityJNI: asset_config.json:
    {
        "id": 1234,
        "name": "asset_config"
    }
2021-04-20 12:41:24.516 26278-26278/com.example.myapp D/MainActivityJNI: Get config path via Environment Variable
2021-04-20 12:41:24.516 26278-26278/com.example.myapp D/MainActivityJNI: /data/user/0/com.example.myapp/files/res_raw_config.json:
    {
        "id": 5678,
        "name": "res_raw_config"
    }