How to specify id when uses include in layout xml file

Specify the ID in the <include>

<include layout="@layout/test" android:id="@+id/test1" />

Then use two findViewById to access fields in the layout

View test1View = findViewById(R.id.test1);
TextView test1TextView = (TextView) test1View.findViewById(R.id.text);

Using that approach, you can access any field in any include you have.