Newbie on mobiles asking for advice: Netrexx, Java, C...?
I'm newbie in this forum and very newbie in mobiles. I am a senior mainframer and I have programmed a lot in Rexx on Mainframes z/OS and PCs (Windows), as well as C on microproccesors.
I have developed a household and I need to process its log IN AN ANDROID MOBILE (no in a PC). The log is a txt file having 130000 short lines; a simple calculation is done per line.
As I do not know mobiles world, I started making easily an app with MIT APP Inventor, but processing log file took 2 hours (!) on my Samsung mobile. Then I made a normal Rexx program running it with "Rexxoid" (by Jaxo) and it took only one minute to process. But I want to make a program which doesn't require another big app like Rexxoid. So I'm trying Netrexx.
But now my doubts:
1. I have copied NetRexxR.jar and my program (myprog.class) to my mobile. But AFAIK Android/Google does not include now Java in their Android mobiles. So How can I run my Netrexx program in mobile? It means, when I issue the following command on the appropriate shell in mobile it says that "java not found":
java -cp NetRexxR.jar:. myprog
2. Can I make an .apk file after compiling with NetRexx?
3. I have read that Google uses Kotlin instead of Java. Should I use Kotlin? How? Everything I read about Kotlin and similars finishes driving me to install more and more applications just to get a "hello world"...
4. I'm afraid that in the end I'll have to program on pure Java with Android developer, but I don't fancy to learn now java just for a simple program like I need. So I'm considering to program in C . Again, I read Google and get instructions to install more and more tools... So, in the end I'm trying C4DROID.
But, before starting a heavy conversion from Rexx to C, I would appreciate very much from you all your hints, suggestions, inputs (and technical help for Netrexx) about my approaches. Of course, what I would really like is to make the program in Rexx distributing then just an .apk file for everybody (or even distributing a .class plus NetRexxR.jar file).