![](https://luckytruedev.com/learning/wp-content/uploads/2018/12/Screen-Shot-2018-12-23-at-08.51.22.png)
As we saw earlier, that Activity is the basic unit of android applications.
UI is defined in the file xml .
During compilation, each element in the XML compiled into class Android GUI similar to the attributes shown by the method.
Display is simply a widget that appears on the screen.
for example: Button, TextView, etc.
Source: Master Android (App)