activity_main.xml

<LinearLayout
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:orientation="vertical"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   tools:context="com.example.farid.ima.MainActivity">

 <Button
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:id="@+id/btnpopup"
       android:text="Popup"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/hello"
        android:text=""/>

</LinearLayout>