Error with ConstraintLayout: No resource found that matches the given name

Question

I learn how to use ConstraintLayout. And have problem.

My activity_test.xml

Answer 1

You are trying to set a constraint based on a element before you define it. So to fix your problem you have two different ways:

First solution: Replace your RelativeLayout(@+id/reserved_layout_search) constrains id values by:

@id/btnScanQRCode -> @+id/btnScanQRCode
@id/btnScanQRCode -> @+id/btnScanQRCode
@id/tvReservedContInfo -> @+id/tvReservedContInfo

Second solution: Declare your btnScanQRCode, btnScanQRCode and tvReservedContInfo widgets before your RelativeLayout on the XML file.