Is there a way to change the gradle.properties file in Unity

Question

Unity has a default gradle.properties file that gets added during the build process. While its possible to change the build.gradle and the settings.gradle files as mentioned

Answer 1

This was something that was slightly hard to discover. I was going to do a regular post build processor like I had for my iOS build, but as I was searching for a manner to load and determine where the properties file was, I ran across the following interface in the documentation : IPostGenerateGradleAndroidProject.

According to the documentation:

Implement this interface to receive a callback after the Android Gradle project is generated.

So below is my initial brute force implementation for turning on androidX and jetifier.

public class AndroidPostBuildProcessor : IPostGenerateGradleAndroidProject
{
    public int callbackOrder
    {
        get
        {
            return 999;
        }
    }


    void IPostGenerateGradleAndroidProject.OnPostGenerateGradleAndroidProject(string path)
    {
        Debug.Log("Bulid path : " + path);
        string gradlePropertiesFile = path + "/gradle.properties";
        if (File.Exists(gradlePropertiesFile))
        {
            File.Delete(gradlePropertiesFile);
        }
        StreamWriter writer = File.CreateText(gradlePropertiesFile);
        writer.WriteLine("org.gradle.jvmargs=-Xmx4096M");
        writer.WriteLine("android.useAndroidX=true");
        writer.WriteLine("android.enableJetifier=true");
        writer.Flush();
        writer.Close();

    }
}

Theoretically you should be able to manipulate the generated gradle project in any manner to your choosing during the post build processor. Some additional tools might be helpful, like the PBXProject support on iOS, but until then, this will do.