A signed apk won't install on my android device

Question

I'm modifying a popular android game (Wrestling Revolution 3D) but I'm having a few problems. Modifying the Flare 3D files is okay. Editing the .swf files are okay. The only thing I can't do is edit the number of body, arm, leg, championship titles, etc. textures in /assets without my phone saying "Application not installed", but I see others doing it. I even signed the all the files (even the .jar file) successfully, but it still says that. It's frustrating. I'm being as specific as I can right now.

Answer 1

If you edit an apk, its signature is no longer valid. You need to resign it, even if with another key. Signing it with another key may break things, depends on the app. It will break updating from the play store.