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Konrad J. Steinkohls Android App Page

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This page provides access to my non-commercial, advertising-free Android Apps. You may download and use everything you find here and consider useful. You may also distribute my apps further, as long as you mention the original source. However, by downloading, installing, copying, or otherwise using the apps, you agree to be bound by all of the terms and conditions of the disclaimer agreement and the legal note.

Please be aware, that I write apps non-commercially and I am lacking the infrastructure to test my apps on a great number of devices. My main focus are small mobil devices like the 'Samsung Galaxy S' series. Some may work on other devices like tablets. It's up to you to try, if interested. My apps will most likely not work with wearables.

If you try apps on other devices I appreciate your feedback!

Quick navigation:
Please read first > Disclaimer | Legal Note < Please read first
Technical stuff: Installation | Feedback
Apps: EierUhr | SnookerStats | SnookerScoreBoard | SnookerCalc
Widgets: Astro Widget


The famous German comedian "Loriot" has already shown, that one of the most important problems in the living together of man and women is "how long does it need to boil an egg" (see "Das Ei"). Fortunately there are scientists, who don't investigate "life, the universe and everything", but look into the real important stuff. One of them is Werner Gruber from the University of Vienna, who provided a formula which answers our question.

Since this formula isn't simple and easy to remember I created an app, which queries the necessary parameters and calculates the boiling time. Additionally it contains a countdown timer, which may be used as egg-timer.

Last stable Version: 2.0
Required permissions: none
System Requirements: Android Version 4.4 or later
Tested on: Samsung Galaxy S4 mini, Android 4.4; Samsung Galaxy S6, Android 6.0

The RedSnookerStats

This app is intended for fans of Snooker sports, in particular for those interested in what's going on in Professional Snooker. There is an excellent web site www.snooker.org, which provides a lot of information.
However, this web site is intended for being used on a big screen. It is hard to read on a smartphone. Fortunately snooker.org provides additionally an API, which allows to retrieve the most important of the data. My App uses this API to look up informations about Professional Snooker (e.g. ranking lists, lists of event, draw of ongoing events) and displays these data in a way appropriate for the screen of a mobile device.
This app requires an internet connection, though the amount of data transferred is relatively small.

Last stable Version: 5.0
Required permissions: none
System Requirements: Android Version 8.0 or later
Tested on: Samsung Galaxy XCover 4, Samsung Galaxy Tab A

New/Changed in version 5.0:

New/Changed in version 4.0:

New/Changed in version 2.0:

New/Changed in version 1.1:

The Score BoardSnookerScoreBoard

This app provides an easy to use Score Board for Snooker Players.
I found several score board apps for snooker on google play. However, I found specific tricky situations, which may occurs during a snooker frame (e.g. red balls potted during a foul or retries after a miss resulting in a correct potted ball), have rarely been handled properly.
Moreover I didn't find one, which calculates the maximal required score for both players to achieve Snookers Required.
So I developed my own score board app. Give it a try, if you like!

Last stable Version: 1.1
Required permissions: none
System Requirements: Android Version 4.4 or later
Tested on: Samsung Galaxy S4 mini, Android 4.4; Samsung Galaxy S6, Android 6.0

The ScoreSnookerCalc

This app is intended for lazy fans of Snooker sports, in particular for those who hate it to do score calculations. Simply provide the current scores and the number of reds on the table. The app will give you the maximal possible score per player. It will also tell you the maximal needed score for reaching Snookers Required.
Please note that the calculation assumes, that the ball currently on is red.

Last stable Version: 1.1
Required permissions: none
System Requirements: Android Version 4.4 or later
Tested on: Samsung Galaxy S4 mini, Android 4.4; Samsung Galaxy S6, Android 6.0

New/Changed in version 1.1:

Astro WidgetAstro Widget

This widget for your "home screen" is a gimmick for those interested in different (mostly astronomical) occurences of date and time. The first line shows in large, friendly letters the current date and time (the time in your time zone). The second line displays from left to right the local mean time, the local apparent time and the sideral time (i.e. the hour angle of the vernal equinox). The last line shows again date and time in the local time zone as "Julian Date".
Sources of formulas used:
Julian Date: https://de.wikipedia.org/wiki/Julianisches_Datum
Sideral Time: https://de.wikipedia.org/wiki/Sternzeit
Local Apparent Time: http://lexikon.astronomie.info/zeitgleichung/neu.html

The calculation of local and sideral times requires the geographic longitude. The desired value has to be entered into the file "astro_widget_geopos" in the "document" folder (typically /sdcard/Documents). During the first start of the widget a prototype of this file is created with the default value 0.0000 (Greenwich).

Regarding the installation::
After installing the APK the widget is available by selecting Menu - Widgets. Click the widget and draw it to the desired position on your home screen.

Last stable Version: 1.1
System Requirements: Android Version 4.4 or later
Tested on: Samsung Galaxy S4 mini, Android 4.4; Samsung Galaxy S6, Android 6.0

New/Changed in version 1.1:


I appreciate any feedback, including bug reports, reports of additional devices my apps have been successfully (or not successfully) run on. And of course also change requests and ideas for improvements.

However - as stated already - these are non-commercial apps, so I will do my best to respond to your input, but it may take some time

Contact me via my Email address: kondroid@ksteinkohl.de


Since my apps are not deployed via the PlayStore you have to undergo several steps (but simple ones) to install an app:

Verifying the Integrity of the APK

All my APKs are signed with a JAVA code signing key. Sadly enough it's not trivial to verify the JAVA code signature. You need a JAVA JDK, which may be downloaded from Oracles JAVA download area.

After the installation of the JDK you will find the "keytool" and the "jarsigner" utility in your JDK (bin-subdirectory).

Unzip the Certificate File from the APK using the following command:
unzip <appname>.apk META-INF/CERT.RSA
Use keytool to print certificate data:
keytool -printcert -f META-INF/CERT.RSA

Verify the following output:

Owner: CN=Konrad J. Steinkohl, ST=Bayern, C=DE
Issuer: CN=Konrad J. Steinkohl, ST=Bayern, C=DE
Serial number: 4b3679da
Valid from: Sun Aug 16 11:38:18 CEST 2015 until: Mon Aug 12 11:38:18 CEST 2030
Certificate fingerprints:
	 MD5:  5F:9E:D1:27:82:B4:11:F8:32:87:CB:1D:8C:54:4D:93
	 SHA1: 10:B1:7C:81:68:CF:34:A9:68:56:0A:A8:98:31:93:E1:53:4A:BC:06
	 SHA256: 24:6E:73:36:B5:FD:3B:E5:C9:27:C8:5C:8F:FF:C9:CF:81:7F:FD:F6:F8:94:98:24:CF:2D:D2:59:CD:15:11:60
	 Signature algorithm name: SHA256withRSA
	 Version: 3

After having verified the certificate, you should finally verify that all components of the APK have been signed with this certificate properly:
jarsigner -verbose -verify <appname>.apk


If you don't want to spend the effort for this verification and you are pretty sure, that you got an APK nobody has tampered with, verify at least during the installation that the requested permissions are reasonable.
Be sure, that I will keep the permission requests as restrictive as possible. So if the App requests for instance permissions to access your contact data or to use your camera or to change your global system configuration be warned, it is most likely not my app, what you are installing. If in doubt contact me before continuing with the installation!



The use of the app is done at your own discretion and risk and with agreement that you will be solely responsible for any damage to your mobile device or loss of data that results from such activities. No advice or information, whether oral or written, obtained by you from the author of the app, its website, its contributors, shall create any warranty for the software.

Legal Note

This is for German Law, so I write this in German only

Goethe sagt im Faust I:

Es erben sich Gesetz' und Rechte
Wie eine ew'ge Krankheit fort';
Sie schleppen von Geschlecht sich zum Geschlechte
Und rücken sacht von Ort zu Ort.
Vernunft wird Unsinn, Wohltat Plage;

Leider hat sich seit den Tagen des alten Geheimrates wohl wenig geändert, deshalb muss ich folgende Klarstellungen aufnehmen, die eigentlich unter vernünftigen Menschen selbstverständlich sein sollten:

Mit Urteil vom 12. Mai 1998 hat das Landgericht Hamburg entschieden, dass man durch die Ausbringung eines Links die Inhalte der gelinkten Seite ggf. mit zu verantworten hat. Dies kann, so das Landgericht Hamburg, dadurch verhindert werden, dass man sich ausdrücklich von diesen Inhalten distanziert.
Ich übernehme keine Haftung für die Inhalte externer Links. Für den Inhalt der verlinkten Seiten sind ausschließlich deren Betreiber verantwortlich.
Ich distanziere mich ausdrücklich von den Inhalten der gelinkten Seiten.

Keine Abmahnung ohne vorherigen Kontakt
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Copyright © 2019 Konrad J. Steinkohl

last Update 2019-11-04