change colors

app/src/main/res/layout/activity_main.xml

@@ -5,10 +5,11 @@
     android:layout_height="match_parent"
     android:orientation="vertical">
 
-    <ListView xmlns:android="http://schemas.android.com/apk/res/android"
+    <ListView
         android:id="@+id/listview2"
         android:layout_width="wrap_content"
-        android:layout_height="wrap_content" />
+        android:layout_height="wrap_content"
+        android:background="@color/colorPrimaryDark"/>
 
     <android.support.design.widget.FloatingActionButton
         android:layout_width="wrap_content"