well, this may be of some future use...maybe not for decompiling software that others don't want you to decompile but w/e.
http://apkmultitool.com/
I personally think that unless you are stealing large amounts of code then you are simply using something as a reference. but then again, i see the world a little bit differently. any of my stuff I make I give away for free though as I feel knowledge should always be free.
I think the concern with these people is that they don't want you to decompile and steal their "innovations" and make a profit from it. however, since you already have most of the work done you are instead comparing and gathering ideas. you aren't going to steal anything of theirs.
now, this link is a bit more "shady" I suppose as you could theoretically use it to steal or crack other's applications that have different types of checks. (Like lucky patcher but a lot more efficient for patching) Now, what is nice about this tool is if you use the correct options then you can see what common methods are used for cracking your app. (suggesting that later on you want to charge for it). the site also gives suggestions for making it more difficult to crack your app. ^_^ I am very pro protecting your stuff correctly.
http://androidcracking.blogspot.com/p/antilvl_01.html
PLEASE UNDERSTAND THAT I AM NOT CONDONING THEFT OF HACKING FOR THE PURPOSE OF HAVING FREE! I enjoy cracking just to say I can but not for use. I actually pay for my apps. ^_^ if it's good enough to crack it's good enough to buy.
anyway, I hope this is helpful to you for the greater good.
