[slf4j-user] SLF4J on the Google Android Platform

[Chiao Cheng]

Hi All,

I was playing around with android and was glad to see that someone already put together a slf4j-android module.  I tried using it and I really like to make some changes so I created another fork.

First, I found an old thread explaining why slf4j-android also includes slf4j-api code...

> I can already tell you that I needed to merge the SLf4J-API project and 
> the new binding implementation into one (Maven) project. The reason is 
> rather complicated to explain. In short, it is due to the fact that 
> SLF4J API removes the dummy impl.* classes during the build from the 
> target Jar, which is not compatible with the Android DexerI'm not sure why this would be the case because the dexer is completely ok with dex'ing multiple jars and dependencies.  I suggest we separate out slf4j-api code from the slf4j-android module.  Once we do this, then it would be easier to keep the two in sync.  With the current setup, it seems like it would be very easy for slf4j-android to fall out of sync with the main api version.  And from the web page, it seems like it has already fallen behind.  I made the appropriate changes (basically stripping out all slf4j-api code from slf4j-android directory) in my fork and it seems to work just fine.  I've tested using android platform 1.6+.

Next, I found a problem in the recent access modifier changes in slf4j.  Specifically the references from LoggerFactory to private StaticLoggerBinder.SINGLETON.  Even though the java runtime seems to be ok due to shortcircuit logic I'm guessing, the android runtime is not:

"access denied from Lorg/slf4j/LoggerFactory; to field Lorg/slf4j/impl/StaticLoggerBinder;.SINGLETON"

For now, I had to change StaticLoggerBinder.SINGLETON back to public to avoid these errors.  But, from looking at the code, I do not see any reasons for LoggerFactory to reference StaticLoggerBinder.SINGLETON, other than allowing some modules to work without a getSingleton() method.  But I would love to remove SINGLETON references in the LoggerFactory.  Also seems a bit hacky to have code that tries to access private members.  Are there plans to get rid of the SINGLETON references completely?

Finally the only other change I made was to remove the systempath in the pom.xml.  Users can simply install a 3rd party jar in their local repository with the provided maven command so there is really no need to have that.  And to make things simpler, there is already an android-maven-plugin which will install the jars for you in your local-repository (http://code.google.com/p/maven-android-plugin/wiki/GettingStarted).

Anyways, my fork is currently working so take a look (http://github.com/chiao/slf4j).  But it would be nice to get the changes into the main trunk to keep up with updates.

Cheers,
Chiao