We make 5 types of layout for each and every Activity
(ldpi, mdpi, hdpi, xhdpi, xxhdpi). For example, for login page we have 5 different layouts. If an application contains more activities, it takes more XML files simultaneously. For example, if an application contains 20 screens, we have to create 100 layouts. It takes more memory space to the application, more time and if we want to add a new attribute in a layout we have to change it in other layouts too.
How to make a single layout screen to fit for all (ldpi, mdpi, hdpi, xhdpi, xxhdpi) devices without changing anything while running the application?