Question

In android studio why @ is used??? to define id we should use @id/tvsomething why here we use @ ??

Answer 1

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In @+id/ the plus symbol + instructs to create a new resource name and add in to the R.java file but what about @id/? From the documentation of ID: when referencing an Android resource ID, you do not need the plus symbol, but must add the android package namespace.

android:id="@android:id/list"

l hope it's help you ♥️☺️