Once you have an APK you want to take a look at you need to extract the contents of it. An APK is really just a jar/zip file. To extract it’s contents just
This will give you a directory with all the resources in it along with a classes.dex file. This file is the compiled Dalvik code. There are a couple of good tools for decompiling the dex. Below is a link to each of them along with instructions on how to run it.
The following will decompile classes.dex into the out_dir of your choice. Just download the Dedexer jar from the link above and rename the jar to ddx.jar or change the command below to reflect the new filename.
java -jar ddx.jar -d out_dir classes.dex
I also recommend taking a look at this presentation on Dedexer on slideshare.
Smali is ‘assembler’ in Icelandic and Baksmali is ‘disassembler’. All we care about right this second is disassembly so you want to download the baksmali jar. I also recommend downloading the wrapper script and the example below assumes you are running baksmali via that wrapper. This will place the decompiled results into a directory called ‘out’.
Doing this is almost a violation of the terms of service for any application you look at so be-careful and use these tools for good.
Update: I created a Textmate bundle for syntax highlighting smali, check it out: http://github.com/steve918/smali-textmate-bundle