Android Studio got very slow and constantly "updating indices"

It also happened to me,I just Sync 'app' and it was solved...

Or use this

Invalidate Caches / Restart under "File Menu"

Also, you can try:

Files -> Invalidate Caches / Restart...

This worked for me.

Try to store Sdk on other drive and also try to invalidate cache and restart. Hope this helps

For the others having the same problem:

My android studio returned back to its original performance (which was ok). It is hard to me to say what made an improvement because I have done lots of changes at once, here are few I recall:

• replaced maven with -> jcenter()
• set flag in properties to use default gradle wrapper
• updated android studio to latest version (at the moment 2.2.3)
• enabled gradle daemon - Configuration On Demand
• invalidate cache and restart(few times)

some of it I have tried before asking this question, but I think all came back to normal when I did last update to Android studio 2.2.3