On Android, Adapter is the bridge between UI components and data sources to help fill data to UI components.
It stores the data and send the data to the display adapter so that the display can retrieve data from the display adapter and display data in different views such as ListView, GridView, Spinner, etc. For more customization in our view using the base adapter or a special adapter.
Here DataSource is the source from which we get the data and UI components is a list or grid items where we want to display that data
Source: Master Android (App)