Unexpected namespace prefix “app” found for tag RelativeLayout - Android?

Question

I need to use BottomSheetBehavior with ScrollView but it says to me :

Unexpected namespace prefix \"app\" found for tag RelativeLayout
         


        

Answer 1

Try setting your xmlns namespace once in the parent layout if you are going to use it multiple times.

xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"

Writing this declaration once in your parent CoordinatorLayout will suffice.

Hint: When using multiple layouts and views, try to implement the <include/> attribute. It will make your code clean and easily readable.