Make Scan button floating

in centre bottom of the screen

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

@@ -1,25 +1,22 @@
-<LinearLayout
-    android:orientation="vertical"
+<RelativeLayout
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
-    <Button
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="@string/button_send"
-        android:id="@+id/buttonScan" />
-
-    <TextView
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="@string/list_header_items"
-        android:paddingTop="12dp" />
-
     <ListView
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:id="@+id/main_items_list"
         tools:listitem="@layout/row_scanned_item" />
-</LinearLayout>
+
+    <ImageButton
+        android:id="@+id/buttonScan"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/button_send"
+        android:layout_centerHorizontal="true"
+        android:layout_alignParentBottom="true"
+        android:src="@drawable/scan_icon"
+        android:layout_marginBottom="@dimen/padding_larger" />
+</RelativeLayout>

app/src/main/res/values/strings.xml

@@ -4,7 +4,6 @@
     <string name="app_name">Maisto Bankas</string>
     <string name="hello_world">Hello world!</string>
     <string name="action_settings">Settings</string>
-    <string name="list_header_items">Prekės</string>
     <string name="button_settings">Nustatymai</string>
     <string name="button_send">Skenuoti</string>
     <string name="barcode_scan_message">Prašome nuskenuoti prekės barkodą</string>