dark mode-v18

app/src/main/java/com/example/login_v3/data/local/UserPreferences/UserPreferences_Repository.kt

@@ -0,0 +1,38 @@
+package com.example.login_v3.data.local.UserPreferences
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences // 確保是這個 Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.emptyPreferences
+import androidx.datastore.preferences.core.stringPreferencesKey
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.map
+import java.io.IOException
+
+
+class UserPreferencesRepository(private val dataStore: DataStore<Preferences>) {
+
+    private object PreferencesKeys {
+        val THEME_MODE = stringPreferencesKey("theme_mode")
+    }
+
+    // 讀取設定：直接在宣告時賦值，簡潔又安全
+    val themeModeFlow: Flow<String> = dataStore.data
+        .catch { exception ->
+            if (exception is IOException) {
+                emit(emptyPreferences())
+            } else {
+                throw exception
+            }
+        }
+        .map { preferences ->
+            preferences[PreferencesKeys.THEME_MODE] ?: "system"
+        }
+
+    suspend fun saveThemeMode(mode: String) {
+        dataStore.edit { preferences ->
+            preferences[PreferencesKeys.THEME_MODE] = mode
+        }
+    }
+}