Example.cs

using System.Linq;
using UnityEditor;

[InitializeOnLoad]
public static class Example
{
    static Example()
    {
        BuildPlayerWindow.RegisterGetBuildPlayerOptionsHandler( OnGetBuildPlayerOptions );
    }

    private static BuildPlayerOptions OnGetBuildPlayerOptions( BuildPlayerOptions buildPlayerOptions )
    {
        buildPlayerOptions.scenes           = EditorBuildSettings.scenes.Select( x => x.path ).ToArray();
        buildPlayerOptions.locationPathName = "app.apk";
        buildPlayerOptions.targetGroup      = BuildTargetGroup.Android;
        buildPlayerOptions.target           = BuildTarget.Android;

        return buildPlayerOptions;
    }
}