2023-09-19

My Web Pages and Android Apps

My Web Pages and Android Apps

Web Pages

I have posted many web pages that might be of interest. They are all linked to my home page. I thought descriptions might be useful.

Cary Ravitz - Home Page -  www.ravitz.us

Contra Dance Links - www.cdl.ravitz.us - My links into the world of contra dance. With links for dancers, callers, choreographers, musicians, sound techs.

Contra Dances by Cary Ravitz - www.dance.ravitz.us - All of my dance stuff - contra dances, contra tunes, waltz tunes, robot dancers, notes on choreography, calling, and dancing.

Ravitz Chess - www.chess.ravitz.us - My stacking/nesting chess piece design. STL files for printing on 3D resin printers.

Ravitz Software - www.rs.ravitz.us - My software, including Android apps, Windows text editor, and old printer graphics software.

Ravitz Violin Shoulder Rest - www.vsr.ravitz.us - My violin shoulder rest. A significant departure from other shoulder rests. I'm am not selling these any longer - too much work.

Contra Dances by Mike Boerschig - www.mike.ravitz.us - Mike's contra dances, including the classic Happy as a Cold Pig in Warm Mud.

Dance Trance Reel by David Atcher - www.atcher.ravitz.us - David Atcher's book of tunes for contra dances (print ready PDF). I edited this for David, 2018, and was given permission to post the PDF when he died, 2020.

Darlene Underwood - Home Page - www.darlene.ravitz.us - Darlene's dance caller home page.

Miscellaneous Contra Dances - www.miscdances.ravitz.us - Contra dances with no other good home. Some nice dances, including the classic Cows Are Watching.

Notes on Composing Contras by Al Olson - www.olson.ravitz.us - Al's handwritten notes for a 1988 workshop, a PDF of scanned pages.

Paintings by Ruth Ravitz - www.ruthpaint.ravitz.us - Scans of mostly water color paintings by my mother. Many beautiful pictures.

Kelly Wilhoit's Hand-Me-Downs PDF - www.ravitz.us/hmd.pdf - A memoir by my mother's sisters of growing up in Atlanta, Georgia starting around 1925.

Android Apps


I wrote four Android phone apps a few years ago. They are seldom used by others - I obviously have no concept of what other people like. But I thought it would be useful to describe what makes them different from other apps that have the same primary function. And I added some technical information about fitting the function into Android, because I think it is interesting.

These apps are completely free, have no advertising, and do not sell or give away any data about you (the weather app accesses your current location but keeps only the most recent location). You can find all four in the Google Play Store by searching on "ravitz" (it's handy to have an uncommon name).

RPN/Postfix Calculator

For a long time, I used Free42, an excellent and free Hewlett Packard 42 emulator. It has two problems - low resolution number display and a cluttered keyboard with function that I don't need (primarily programming - it's easier to program a desktop computer or spreadsheet than a calculator).

So my calculator has no programming function. I added cursor left and right for improved number editing, display of the full stack, plus undo, help, last key display, and some button configuration flexibility.

The finished app looks good. Numbers are presented in a high resolution font. The button response isn't as good as it should be, I think largely because I check for a valid number after each keystroke - maybe not a good choice.

Tech paragraph - I wrote the calculator in JavaScript/HTML and used Android's Webview to turn it into an app. Android has a simple way of communicating between the Android Java and Webview JavaScript. You can turn any web page into an Android app pretty easily, or there is an app that does the job with almost no programming.

Clock Widget

I wanted a simple clock widget that displayed the time and day/ And I wanted the time zone displayed. When traveling and on two late nights every year, it is not always obvious what time zone you are in. Why not have the complete time displayed?

In addition, the next alarm time is very useful. I use my phone as an alarm clock. Before going to sleep I would like an easy verification that the alarm is set correctly.

Plus size and color flexibility. I think this is a great clock widget.

Interesting that my clock widget and car sometimes differ on the time zone, notably on the western edge of Kansas. The car changes the time at the border. The clock widget (Android) knows that is not where the time zone changes.

Tech paragraph - This requires setting up a widget that sleeps until awaken by a system message, such as next alarm changed. Then it changes the display and goes back to sleep. Time updates are automatic and trivial to program.

MP3 Player

I don't care to subscribe to a music service. I am happy buying MP3 music files from Amazon or copying music from my CD collection. I was very upset once when flying across the country and my music player quit because it couldn't verify that I had paid for it. I want a self contained music system.

And music players do not handle tracks with different volume levels very well. My player lets you add a volume bump to each track or track list.

And it tells you how much time is left in the current track list, so I know if an album will finish before the evening news starts.

Plus optional bass, upper midrange, treble controls instead of Android's separate graphic equalizer.

I'm very happy with the result. I use it often.

Tech paragraph - The user interface is via Webview. Turning MP3 and other music files into music is a simple system function. Keeping the music going while other software is running or the phone goes to sleep requires using an Android foreground service - not simple.

Weather Widget


It's nice to glance at the phone screen and get an overview of the weather. A lot of weather widgets do this, but they tend to be huge (screen area). And are more concerned with being pretty than being informative. After finding a free weather service, maybe not the best forecasts, and navigating Android's background issues, I put together a reliable widget. I added a one page pop up 36 hour hourly forecast to it because that gives you a lot of useful information. And I added a location and forecast update verification line so you know that you are getting timely and location relevant information (not always the case when you are traveling or have a poor internet signal).

This is much more useful than the typical small weather icon. And much smaller than the typical large weather widget. No pretty pictures - after much work, it became apparent that words were a much more compact way to communicate.

Tech paragraph - This uses the sleeping widget concept, like the clock widget. It is awakened via system message, requests a new location, and goes to sleep. Then it is awakened by a location response, gets a new forecast from an internet weather service, updates the display, and goes back to sleep. Not fun - preparing a Google approved procedure to get user permission to access location services in the background.

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