add comparison between compose state and stateflow

initScreenData/app/src/main/java/io/github/aniokrait/androidtoybox/ui/screen/SampleScreen.kt

@@ -0,0 +1,8 @@
+package io.github.aniokrait.androidtoybox.ui.screen
+
+import androidx.compose.runtime.Composable
+
+@Composable
+fun SampleScreen() {
+
+}

initScreenData/app/src/main/java/io/github/aniokrait/androidtoybox/ui/viewmodel/SampleViewModel.kt

@@ -0,0 +1,26 @@
+package io.github.aniokrait.androidtoybox.ui.viewmodel
+
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.State
+import androidx.compose.runtime.mutableStateOf
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+@HiltViewModel
+class SampleViewModel: ViewModel() {
+    private val _state: MutableState<String> = mutableStateOf("")
+    val state: State<String> = _state
+    fun superLongAsyncMethod() {
+        viewModelScope.launch {
+            withContext(Dispatchers.IO) {
+                delay(10000000000)
+            }
+            _state.value = "取得終了"
+        }
+    }
+}

stateComparison/app/src/main/java/io/github/aniokrait/androidtoybox/MainActivity.kt

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+package io.github.aniokrait.androidtoybox
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import io.github.aniokrait.androidtoybox.ui.viewmodel.MainViewModel
+
+class MainActivity: ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            val vm: MainViewModel = viewModel()
+            val composeCount = vm.composeCount
+            val flowCount by vm.flowCount.collectAsState()
+
+            Column(
+                modifier = Modifier.fillMaxSize(),
+                verticalArrangement = Arrangement.spacedBy(8.dp),
+                horizontalAlignment = Alignment.CenterHorizontally
+            ) {
+                Button(onClick = { vm.generateNewComposeCount() }) {
+                    Text("Compose Stateのカウント: $composeCount")
+                }
+
+                Button(onClick = { vm.generateNewFlowCount() }) {
+                    Text("flowCountのカウント: $flowCount")
+                }
+            }
+        }
+    }
+}

stateComparison/app/src/main/java/io/github/aniokrait/androidtoybox/ui/viewmodel/MainViewModel.kt

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+package io.github.aniokrait.androidtoybox.ui.viewmodel
+
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlin.random.Random
+
+class MainViewModel constructor(
+    private val savedStateHandle: SavedStateHandle
+): ViewModel() {
+    //StateFlowの宣言
+//    private val _flowCount = MutableStateFlow(0)
+//    val flowCount = _flowCount.asStateFlow()
+    //StateFlowの宣言（savedStateHandleを使う場合）
+    val flowCount = savedStateHandle.getStateFlow("count", 0)
+
+    //Compose Stateの宣言
+    var composeCount by mutableStateOf(
+//        0
+        //savedStateHandleを使う場合
+    savedStateHandle.get<Int>("count") ?: 0
+    )
+        private set
+
+    fun generateNewComposeCount() {
+        val newCount = Random.nextInt(1000)
+        //savedStateHandleを使う場合
+        savedStateHandle["count"] = newCount
+        //savedStateHandleを使う場合もCompose Stateへの代入は必要
+        composeCount = newCount
+    }
+
+    fun generateNewFlowCount() {
+        val newCount = Random.nextInt(1000)
+//        _flowCount.value = newCount
+        //savedStateHandleを使う場合
+        savedStateHandle["count"] = newCount
+    }
+}