Checkers Tutor 2.1

I just posted Checkers Tutor 2.1 for Android on the Android market. It has a lot of improvements over the previous version:

• Nicer graphics (see previous post)and new nicer launcher icon
  
• A new pushover level where you should be able to win even when moving at random
  
• A smoother transition of playing strength when moving up from beginner levels to depth-controlled levels to timed levels. This is done by disabling parts of the evaluation on the lower depth-controlled levels
  
• The entire last game is restored now on startup, not only the last position
  
• Two small bugs fixed
  
• Behind the scenes, a lot of the code was cleaned up
  

To me, it looks as if it should be the best/nicest checkers app for the Android platform, but obviously I'm rather biased! Now all I need is some customers and some good ratings :-)

Playing with graphics for Android checkers

Over the weekend, my wife went on a short hike with our kid and his godmother, giving me a bit of time to play around with the checkers tutor graphics. Here's my current preview, and I think I will leave it at that - I like the looks of it!



I increased the size of the pieces a bit, and used Inkscape to produce pieces with gradients and highlights. Obviously I'm not a graphic artist, but I think they are much nicer than the plain circles I used to have.

Android checkers reloaded

During my x-mas holidays, disappointed with the measly 5000 downloads I got over one year of my free Android Checkers Tutor App, I came up with a great plan: make it a paid app instead of free - like that, all the people who know nothing at all about checkers won't download it and won't complain about the must-capture-rule, and won't give it bad ratings. Great plan, but with 6 sales in 40 days, it didn't really work out... Not one to give up easily, I have decided to revamp it a bit. I've started making the code cleaner behind the scenes, and also tried to improve the looks of the app. Not too sure about whether it's an improvement - what do you think?

common Java codebase

I worked a bit on my Java checkers engine so that I can now use the same code for both my Android checkers tutor and my Java PC program - I'm glad I managed to combine the two! The only difference (and one I will probably forget to change from time to time...) is the size of the hashtable, which is obviously much smaller on the phone.
I also improved playing strength a bit, and will probably release new versions of both my Java checkers programs soon.

Checkers Tutor reaches 1000 downloads

Today, following another download-increasing update to version 1.06, Checkers Tutor has reached over 1000 total downloads. For reasons unclear to me (and from reading on the internet, everybody else too), Google does not offer a PC interface to the Android market, and therefore there are 3rd party websites that do offer such an interface. I use AndroLib, where I can see how many ratings and comments I got, and how the ratings develop over time. Apparently, Checkers Tutor has a rating of 3.33 out of 5, after 9 ratings. Unfortunately, not a single comment on what could be improved...
Androlib also has some download statistics. According to these, of currently 23'477 apps, 61.6% have been downloaded less than 1000 times. So CT is in the top 38.4% of all apps; and only 19.9% of all apps (or 4672) are in the category above with more than 5000 downloads. So CT isn't doing too bad, then again the other checkers programs out there are doing better or much better - and when I run out of upgrade ideas, my downloads will slow down to a trickle once again. I have two upgrade ideas left, but then it will be time to leave CT to its own devices on Android market.

Checkers Tutor 1.04, 1.05 etc.

The Android market has a developer console which tells developers how often their application has been downloaded, how many active installations of it there are, and how the application is rated by the users. These stats are interesting, but not really up to Google standards - for example, you have no clue about how your downloads are distributed over time, and I have been logging in to my dev console every night to see how my Checkers Tutor is doing (it would be so much nicer if daily/weekly/monthly stats were available...). I have noticed that whenever I publish an update of Checkers Tutor, the number of downloads increases massively. I can also see that the number of active installs increases too, so I guess that my app is more visible on the Android market for perhaps a day after an update (but this is pure speculation). Anyway, seeing that my download stats are disappointing, I will be making some incremental updates to Checkers Tutor in the hope of attracting more users (1.04 released, 1.05 going up tonight, and 1.06 already planned), and perhaps gaining visibility in the Android Market (which is probably a combination of downloads and rating, but again this is guesswork). One problem which all checkers apps seem to have in common is that many people don't know that you must capture if you can in checkers. Aart Bik's Checkers for Android is by far the most downloaded checkers app, and it seems that about half of it's comments are "stupid - computer cheats" or "don't install - can't make moves I want to". And the ratings are correspondingly low. Unfortunately, Aart put in an option to make captures optional in his program, which is a bit of a shame because these people should learn how to play checkers for real...

Checkers Tutor 1.03

I just published version 1.03 of Checkers Tutor on the Android Market. It has improved move input, displays the current level in the title bar, displays the last move with a blue arrow instead of not-so-nice highlighted squares, and fixes a bug in the arrow rendering for capture moves when the board is flipped. Behind the scenes, I cleaned up a bit again, but my board class is still a God Object which isn't nice. The screenshot below shows how it looks (still quite similar to version 1.0!).


Checkers Tutor has some features that are better than what I have in CheckerBoard

• The move input is smarter: clicking on a piece that only has one legal move immediately executes that move (like in CheckerBoard), but also clicking on a square that can only be reached by one piece executes that move (unlike in CheckerBoard). This is nice because on those tiny mobile phone screens it's probably not easy to input moves, and every click you can save helps.
  
• All legal moves can be displayed with yellow arrows to teach the rules.
  
• The last move played can be shown with a blue arrow.
  
• The beginner level attempts to reach a bad (but not immediately losing) position at all times. This should avoid frustration for beginners, who are usually not happy with my PC programs because they lose too often.
  

Some other things are not so nice yet:

• The checkers engine is not as strong as I would like it to be. A large part of this is the low speed of the hardware, but I must admit that I haven't worked too hard on improving my Java checkers engine. It will most probably be more than good enough for 99% of the users. Nevertheless, a small opening book and perhaps endgame databases up to 4 pieces would greatly enhance its play, as would some more work on the evaluation function.
  
• The game is not saved when you quit and return (or when you switch the display from portrait to landscape mode or vice versa), only the current position. You cannot undo any moves made in the last session.
  
• There is not much advice to help a novice what to do with the game after installation. I would like to add something like Tips on Startup to improve this.
  
• Move input is limited to touch, but perhaps on phones with small screens this is not practical, and adding keyboard support would be nice.
  
• And probably many other things that I forget...
  

However, my christmas holidays are coming to an end, so the next update will have to wait a bit.

Checkers Tutor 1.02

In the 5 days since the publication of Checkers Tutor for Android, I fiddled around with it a bit. I added a feature to display all legal moves in the current position (it claims to be a tutor after all...), and I fixed some minor bugs: v1.02 now also displays properly in the landscape mode and the board numbers scale better (also on hi-res devices). Behind the scenes, I cleaned up the user interface code a bit to make it more readable, maintainable and less bug-prone. As usual with this cleaning business, it never actually ends. My board class has more than 700 lines of code, and after reading Robert C. Martin's nice book titled Clean Code, I must assume that that is too much, and besides I find a couple of the code smells he lists in my code...
These things aside, I'm afraid that my Checkers Tutor has missed the boat anyway - it got 228 downloads in its first 5 days, which means nearly none compared to Aart Bik's Checkers for Android, which apparently got over 250'000 downloads in one year (see Aart's blog for more information). This is the usual punishment for coming late to the party - I could have published Checkers Tutor in August, but somehow felt I should still add zillions of features to make it better than Aart's app - in the end I never added these features, and the early bird has caught the worm - the attention of the Android Market, where often-downloaded programs are more visible, and thus go in a positive feedback loop.

Checkers Tutor for Android published!

I finally got round to publishing my Android checkers program - it *should* be available on the Android market under the name "Checkers Tutor" - but since I don't have an Android phone I have no way of knowing whether it really is there!

Checkers for Android Phones

It's been a while since I worked on my Java program. Actually, the underlying purpose of writing a Java checkers program was to (1) learn Java and (2) write a checkers program for the Android operating system running on the Google phones. There are two checkers programs for the iPhone based on my simple checkers engine, and since developing for the iPhone seems to be a PITA or at least some kind of licensing hell, I was never interested. The much more open philosophy of Android attracted me however, and my checkers program is already running on my emulator. It manages to search about 5000 positions per second, i.e. it's nearly 1000x slower than my corresponding PC program, and therefore also quite a bit weaker. But since it incorporates a lot of the stuff that I learned during the many years of programming Cake, it plays a decent game nevertheless. I worked hard on it during the last two weeks on my mountain holidays (whenever I wasn't climbing the mountains), and it's already a working program. However, I may have overdone things a bit trying to put a lot of features into the program, so it won't be ready today or tomorrow, but hopefully before the summer is out.