diff --git a/app/src/main/java/com/t/saito/pr_agent_sample/DemoRepository.kt b/app/src/main/java/com/t/saito/pr_agent_sample/DemoRepository.kt
new file mode 100644
index 0000000..087d81f
--- /dev/null
+++ b/app/src/main/java/com/t/saito/pr_agent_sample/DemoRepository.kt
@@ -0,0 +1,28 @@
+package com.t.saito.pr_agent_sample
+
+class DemoRepository {
+
+    val demoItems = mutableListOf<String>()
+
+    fun addAllItem(items: List<String>): List<String> {
+        demoItems.addAll(items)
+        return demoItems
+    }
+
+    fun addItem(item: String): List<String> {
+        demoItems.add(item)
+        return demoItems
+    }
+
+    fun firstItem(): String? {
+        return demoItems.firstOrNull()
+    }
+
+    fun lastItem(): String? {
+        return demoItems.lastOrNull()
+    }
+
+    fun clear() {
+        demoItems.clear()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/t/saito/pr_agent_sample/DemoUseCase.kt b/app/src/main/java/com/t/saito/pr_agent_sample/DemoUseCase.kt
new file mode 100644
index 0000000..bba94e1
--- /dev/null
+++ b/app/src/main/java/com/t/saito/pr_agent_sample/DemoUseCase.kt
@@ -0,0 +1,25 @@
+package com.t.saito.pr_agent_sample
+
+class DemoUseCase(
+    private val repository: DemoRepository
+) {
+
+    fun addAllItem(items: List<String>): List<String> {
+        return repository.addAllItem(items)
+    }
+    fun addItem(item: String): List<String> {
+        return repository.addItem(item)
+    }
+
+    fun firstItem(): String? {
+        return repository.firstItem()
+    }
+
+    fun lastItem(): String? {
+        return repository.lastItem()
+    }
+
+    fun clear() {
+        repository.clear()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/t/saito/pr_agent_sample/DemoViewModel.kt b/app/src/main/java/com/t/saito/pr_agent_sample/DemoViewModel.kt
new file mode 100644
index 0000000..3e53570
--- /dev/null
+++ b/app/src/main/java/com/t/saito/pr_agent_sample/DemoViewModel.kt
@@ -0,0 +1,52 @@
+package com.t.saito.pr_agent_sample
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.launch
+
+class DemoViewModel(
+    private val demoUseCase: DemoUseCase
+) : ViewModel() {
+
+    private val _pageFlag = MutableStateFlow<Boolean>(false)
+    val pageFlag: SharedFlow<Boolean> get() = _pageFlag
+
+    fun onClickAddItem() {
+        demoUseCase.addItem("item")
+    }
+    fun onClickAddAllItems() {
+        demoUseCase.addAllItem(listOf("item1", "item2", "item3"))
+    }
+
+    fun onClickFirstItem() {
+        demoUseCase.firstItem()
+    }
+
+    fun onClickLastItem() {
+        demoUseCase.lastItem()
+    }
+
+    fun onClickClear() {
+        demoUseCase.clear()
+    }
+
+    fun onClickPageSwitch() {
+        viewModelScope.launch {
+            val pageFlag = _pageFlag.value
+            _pageFlag.emit(pageFlag.not())
+        }
+    }
+}
+
+class DemoViewModelFactory(
+    private val demoUseCase: DemoUseCase
+) : ViewModelProvider.Factory {
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        return DemoViewModel(
+            demoUseCase = demoUseCase,
+        ) as T
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/t/saito/pr_agent_sample/MainActivity.kt b/app/src/main/java/com/t/saito/pr_agent_sample/MainActivity.kt
index 747efa5..971ad34 100644
--- a/app/src/main/java/com/t/saito/pr_agent_sample/MainActivity.kt
+++ b/app/src/main/java/com/t/saito/pr_agent_sample/MainActivity.kt
@@ -3,26 +3,50 @@ package com.t.saito.pr_agent_sample
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.activity.viewModels
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.wrapContentSize
+import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
+import com.t.saito.pr_agent_sample.ui.DemoScreen
 import com.t.saito.pr_agent_sample.ui.theme.PragentsampleTheme
 
 class MainActivity : ComponentActivity() {
+
+    private val demoViewModel by viewModels<DemoViewModel> {
+        DemoViewModelFactory(
+            DemoUseCase(
+                DemoRepository()
+            )
+        )
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
             PragentsampleTheme {
                 // A surface container using the 'background' color from the theme
+                val flag by demoViewModel.pageFlag.collectAsState(false)
                 Surface(
                     modifier = Modifier.fillMaxSize(),
                     color = MaterialTheme.colorScheme.background
                 ) {
-                    Greeting("Android")
+                    if(flag) {
+                        DemoScreen(
+                            demoViewModel = demoViewModel,
+                        )
+                    } else {
+                        Greeting(name = "Android", onClick = {
+                            demoViewModel.onClickPageSwitch()
+                        })
+                    }
                 }
             }
         }
@@ -30,17 +54,25 @@ class MainActivity : ComponentActivity() {
 }
 
 @Composable
-fun Greeting(name: String, modifier: Modifier = Modifier) {
-    Text(
-        text = "Hello $name!",
-        modifier = modifier
-    )
+fun Greeting(
+    name: String,
+    onClick: () -> Unit = {}
+) {
+    Button(
+        onClick = onClick,
+        modifier = Modifier.wrapContentSize()
+    ) {
+        Text(
+            text = "Hello $name!",
+        )
+    }
+
 }
 
 @Preview(showBackground = true)
 @Composable
 fun GreetingPreview() {
     PragentsampleTheme {
-        Greeting("Android")
+        Greeting(name = "Android")
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/t/saito/pr_agent_sample/ui/DemoScreen.kt b/app/src/main/java/com/t/saito/pr_agent_sample/ui/DemoScreen.kt
new file mode 100644
index 0000000..fb3de28
--- /dev/null
+++ b/app/src/main/java/com/t/saito/pr_agent_sample/ui/DemoScreen.kt
@@ -0,0 +1,38 @@
+package com.t.saito.pr_agent_sample.ui
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.t.saito.pr_agent_sample.DemoViewModel
+
+@Composable
+fun DemoScreen(
+    demoViewModel: DemoViewModel,
+) {
+    Column(
+        modifier = Modifier.fillMaxWidth(),
+        horizontalAlignment = androidx.compose.ui.Alignment.CenterHorizontally
+    ) {
+        Button(onClick = { demoViewModel.onClickAddItem() }) {
+            Text("Add Item")
+        }
+        Button(onClick = { demoViewModel.onClickAddAllItems() }) {
+            Text("Add All Items")
+        }
+        Button(onClick = { demoViewModel.onClickClear() }) {
+            Text("Clear")
+        }
+        Button(onClick = { demoViewModel.onClickFirstItem() }) {
+            Text("First Item")
+        }
+        Button(onClick = { demoViewModel.onClickLastItem() }) {
+            Text("Last Item")
+        }
+        Button(onClick = { demoViewModel.onClickPageSwitch() }) {
+            Text("back")
+        }
+    }
+}
\ No newline at end of file