Just as a hint; this is how many "secure" Android apps check for a rooted phone

gtfo.java

import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;

final class zx
{

    private static boolean a()
    {
        String s;
        ArrayList arraylist = xe.a(new String[] {
            "/system/bin/getprop", "ro.secure"
        });
        if(arraylist.isEmpty())
            return false;
        s = (String)arraylist.get(0);
        int j = Integer.parseInt(s);
        int i = j;
_L1:
        NumberFormatException numberformatexception;
        return i == 0;
        numberformatexception;
        i = 0;
          goto _L1
    }

    public static boolean a(Context context)
    {
label0:
        {
            String s = Build.TAGS;
            boolean flag;
            if(s != null && s.contains("test-keys"))
                flag = true;
            else
                flag = false;
            if(!flag && !(new File("/system/app/Superuser.apk")).exists())
            {
                boolean flag1;
                boolean flag2;
                if((new File("/system/xbin/which")).exists())
                {
                    if(!xe.a(new String[] {
    "/system/xbin/which", "su"
}).isEmpty())
                        flag2 = true;
                    else
                        flag2 = false;
                } else
                {
                    flag2 = false;
                }
                if(!flag2 && !b(context) && !a())
                {
                    boolean flag3 = b();
                    flag1 = false;
                    if(!flag3)
                        break label0;
                }
            }
            flag1 = true;
        }
        return flag1;
    }

    private static boolean a(Context context, String s)
    {
        try
        {
            context.getPackageManager().getPackageInfo(s, 8192);
        }
        catch(android.content.pm.PackageManager.NameNotFoundException namenotfoundexception)
        {
            return false;
        }
        return true;
    }

    private static boolean b()
    {
        ArrayList arraylist = xe.a(new String[] {
            "/system/bin/ps", ""
        });
        if(arraylist.isEmpty())
            return false;
        arraylist.remove(0);
        for(Iterator iterator = arraylist.iterator(); iterator.hasNext();)
        {
            String s = (String)iterator.next();
            if(s.contains("/sbin/adbd"))
                return s.contains("root");
        }

        return false;
    }

    private static boolean b(Context context)
    {
        if(context != null)
        {
            String as[] = {
                "com.noshufou.android.su", "com.thirdparty.superuser", "eu.chainfire.supersu", "com.koushikdutta.superuser", "com.zachspong.temprootremovejb", "com.ramdroid.appquarantine"
            };
            for(int i = 0; i < 6; i++)
                if(a(context, as[i]))
                    return true;

        }
        return false;
    }
}