This is a comprehensive .gitignore for AndroidStudio 1.5, since the default .gitignore generated causes all sorts of headaches when sharing across .git. Basically, it treats the project as a pure gradle project as opposed to Android Studio one. Credit goes to authors in links.

.gitignore

# https://code.google.com/p/android/issues/detail?id=156708
# http://stackoverflow.com/questions/16736856/what-should-be-in-my-gitignore-for-an-android-studio-project

*.iml
.gradle
/local.properties
/.idea/workspace.xml
/.idea/libraries
.DS_Store
/build
/captures

#built application files
*.apk
*.ap_

# files for the dex VM
*.dex

# Java class files
*.class

# generated files
bin/
gen/

# Local configuration file (sdk path, etc)
local.properties

# Windows thumbnail db
Thumbs.db

# Eclipse project files
.classpath
.project

# Android Studio
.idea/
/*/local.properties
/*/out
/*/*/build
/*/*/production
*.iws
*.ipr
*~
*.swp

#NDK
obj/