android - Resource scope for @+id/ declarations? -

when working through tutorial build first android application reached section states @+id/ prefix not references resource defined in gen/r.java file, + sign indicates first encounter create it. consider code snippet:

<edittext android:id="@+id/edit_message"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:hint="@string/edit_message" /> 

after reading through side-bar in first link, related resources, , article linked named providing resources (at cursory level), i'm unable clear statement documentation on scope of resource @+id/ prefix. understand can have resource same name scoped inside each prefix:

note: string resource has same name element id: edit_message. however, references resources scoped resource type (such id or string), using same name not cause collisions.

but i'm driving @ this. based on documentation appears can't have 2 controls resourced edit_message in 2 different activities because there conflict.

my concern here i'd presumably have prefix id attributes activity name keep them unique can access these controls code.

am correct in statement , assumptions here?

you can place exact block of xml in layout file , work fine. @+id generates new id if not defined yet. when app gets packaged, packaging tool create id once , others correctly refer id.

as long don't end 2 ui components in same layout same id, everything's ok.