What is .idea folder in Android Studio 3.2.12?

Question

I meet the problem Cannot resolve symbol AppCompatActivity

I solved the problem by deleting .idea folder and syncing project with gradle files by the acticle Cannot resolve symbol AppCompatActivity - Support v7 libraries aren't recognized?

Could tell me what .idea folder is ? Why can I delete it and sync ?

Answer 1

.idea folder is storing the settings for your IDE (Development Environment) - so the settings of Android Studio how to visualize your project. You can check more about .idea folder here

Answer 2

The .idea folder (hidden on OS X) in the solution root contains IntelliJ's project specific settings files. These include per-project details such as VCS mapping and run and debug configurations, as well as per-user details, such as currently open files, navigation history and currently selected configuration.

Some files should be committed to source control, some should be excluded.

See here: https://rider-support.jetbrains.com/hc/en-us/articles/207097529-What-is-the-idea-folder-