When we create android project , android studio creates directory structure that contains each and everything which defines our workspace for an android application.
Manifests folder contain AndroidManifest.xml file. This manifest file contains all information about our application such as application name , app icon. We Declare permissions and components in AndroidManifest.xml file
Java folder contains java source code (.java file). We will create java files inside this folder. As you can see in above picture java package ( hackodia.helloworld ) made inside java folder.
res folder also known as resource folder. This folder play very important role in android application development. This folder contains many folder such as drawble , layout , mipmap and values.
Inside drawable folder we put all types of image files.
Inside layout folder we put or create layout files . Inside layout files we write xml code to create user interface.
mipmap folder contains application launcher icon. This folder contains five types of images because they are used at resolutions different from the device's current density.
This folder also known as resource provider folder. strings.xml , color.xml and style.xml files resides inside values folder.