arrange main recyclerview to center

@@ -2,8 +2,11 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:orientation="vertical"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_width="100dp"
+    android:layout_height="100dp"
+    android:layout_gravity="center"
+    android:layout_margin="20dp"
+    android:gravity="center">
 
 
     <ImageView
@@ -13,7 +16,8 @@
         app:layout_constraintLeft_toLeftOf="parent"
         app:layout_constraintRight_toRightOf="parent"
         app:layout_constraintTop_toTopOf="parent"
-        android:adjustViewBounds="true"/>
+        android:adjustViewBounds="true"
+        android:layout_gravity="center"/>
 
     <TextView
         android:id="@+id/fieldIconText"
@@ -22,6 +26,7 @@
         android:textSize="20sp"
         app:layout_constraintTop_toBottomOf="@+id/fieldIcon"
         app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"/>
+        app:layout_constraintRight_toRightOf="parent"
+        android:layout_gravity="center"/>
 
 </LinearLayout>
\ No newline at end of file

@@ -7,8 +7,8 @@
     <string name="title04">건강</string>
     <string name="title05">서민금융</string>
     <string name="title06">문화</string>
-    <string name="title07">Performance Analysis Using Systrace (Android Dev Summit 18)</string>
-    <string name="title08">Preferential Practices for Preferences (Android Dev Summit 18)</string>
-    <string name="title09">That’s a wrap on Android Dev Summit 2018!</string>
-    <string name="title10">Vitals: Past, Present and Future (Android Dev Summit 18)</string>
+    <string name="title07">빈카테고리</string>
+    <string name="title08">빈카테고리</string>
+    <string name="title09">빈카테고리</string>
+    <string name="title10">빈카테고리</string>
 </resources>