diff --git a/app/src/main/java/jackall/devrealm/viewmodel/ItemViewModel.kt b/app/src/main/java/jackall/devrealm/viewmodel/ItemViewModel.kt
index de62ecd..6343593 100644
--- a/app/src/main/java/jackall/devrealm/viewmodel/ItemViewModel.kt
+++ b/app/src/main/java/jackall/devrealm/viewmodel/ItemViewModel.kt
@@ -14,9 +14,11 @@
 
     init {
         person.addChangeListener<Person> { person ->
-            firstName.set(person.firstName)
-            lastName.set(person.lastName)
-            age.set(person.age.toString())
+            if (person.isValid) {
+                firstName.set(person.firstName)
+                lastName.set(person.lastName)
+                age.set(person.age.toString())
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/jackall/devrealm/viewmodel/MainViewModel.kt b/app/src/main/java/jackall/devrealm/viewmodel/MainViewModel.kt
index a9e41b5..c0eef88 100644
--- a/app/src/main/java/jackall/devrealm/viewmodel/MainViewModel.kt
+++ b/app/src/main/java/jackall/devrealm/viewmodel/MainViewModel.kt
@@ -5,9 +5,11 @@
 import android.databinding.BindingAdapter
 import android.support.v7.widget.LinearLayoutManager
 import android.support.v7.widget.RecyclerView
+import android.view.View
 import jackall.devrealm.App
 import jackall.devrealm.adapter.MainAdapter
 import jackall.devrealm.db.PersonRealmHelper
+import jackall.devrealm.vo.Person
 import java.util.*
 
 /**
@@ -37,6 +39,23 @@
         adapter = MainAdapter(App.instance, items)
     }
 
+    fun onClickAdd(view: View) {
+        personRealmHelper.insert(
+                Person(
+                        age = Random().nextInt(100),
+                        firstName = "firstName(${Random().nextInt(100)})",
+                        lastName = "lastname(${Random().nextInt(100)})"
+                )
+        )
+    }
+
+    fun onClickRemove(view: View) {
+        personRealmHelper.findLast().let { person ->
+            if (person != null)
+                personRealmHelper.delete(person)
+        }
+    }
+
     override fun onDestroy() {
         super.onDestroy()
         personRealmHelper.close()
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 893ef7c..0436a9a 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     tools:context="jackall.devrealm.activity.MainActivity">
 
@@ -14,10 +15,34 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
+        <Button
+            android:id="@+id/db_add_button"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:onClick="@{mainViewModel.onClickAdd}"
+            android:text="@string/add"
+            app:layout_constraintEnd_toStartOf="@id/db_remove_button"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent" />
+
+        <Button
+            android:id="@+id/db_remove_button"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:onClick="@{mainViewModel.onClickRemove}"
+            android:text="@string/remove"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toEndOf="@id/db_add_button"
+            app:layout_constraintTop_toTopOf="parent" />
+
         <android.support.v7.widget.RecyclerView
-            android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:setMainAdapter="@{mainViewModel.adapter}" />
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:setMainAdapter="@{mainViewModel.adapter}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/db_add_button" />
 
     </android.support.constraint.ConstraintLayout>
 </layout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 2b2ea72..8b7aeca 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1,4 +1,6 @@
 <resources>
     <string name="app_name">DevRealm</string>
+    <string name="add">追加</string>
+    <string name="remove">削除</string>
     <string name="age">歳</string>
 </resources>