How can unity interact with android natively?

I'm trying to make a wallpaper and am at a loss as to how unity can interact with the android api and file system. After looking around, I found two plugins unity2eclipse (which is outdated (works for unity 3.4)) and uLiveWallpaper:

https://assetstore.unity.com/packages/tools/integration/ulivewallpaper-indie-52110

While these plugins may be helpful in creating wallpapers, I'm not sure how well they interface with the file system (I'll need to download config files and read them from the app).

Is there any documentation on this topic?

 

If you can find out how to do it in Java, the language of choice for Android, then you can use the following to call Java code.

https://docs.unity3d.com/ScriptReference/AndroidJavaObject.html

It is not the best documented feature, if you need an example, let me know.

 

Here is how I get the Android devices locale by calling Java code:

Code (CSharp):

1. private static string GetAndroidLocale()
2. {
3.     AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
4.     AndroidJavaObject currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
5.     AndroidJavaObject currentResources = currentActivity.Call<AndroidJavaObject>("getResources");
6.     AndroidJavaObject currentConfiguration = currentResources.Call<AndroidJavaObject>("getConfiguration");
7.     AndroidJavaObject currentLocale = currentConfiguration.Get<AndroidJavaObject>("locale");
8.  
9.     string javaCountry = currentLocale.Call<string>("getCountry");
10.     string javaLanguage = currentLocale.Call<string>("getLanguage");
11.  
12.     return $"{javaLanguage}-{javaCountry}";
13. }

This is the equivalent of calling currentActivity.getResources().getConfiguration().locale.getCountry() / getLanguage() in Java.