Implement Compose SimpleMenuPreference 2

app/src/main/java/com/hippo/ehviewer/Settings.kt

@@ -111,6 +111,7 @@ object Settings : DefaultPreferences() {
     var proxyIp by stringOrNullPref("proxy_ip", null)
 
     var dohUrl by stringPref("doh_url", "")
+    var language by stringPref("app_language", "system").apply { changesFlow().observe { updateWhenLocaleChanges() } }
     var lastDawnDay by longPref("last_dawn_day", 0)
 
     init {

app/src/main/java/com/hippo/ehviewer/SettingsCollector.kt

@@ -0,0 +1,22 @@
+package com.hippo.ehviewer
+
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.os.LocaleListCompat
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.launch
+
+val collectScope = CoroutineScope(Dispatchers.Main + SupervisorJob())
+
+fun Flow<Unit>.observe(func: (Unit) -> Unit) = collectScope.launch { collect(func) }
+
+fun updateWhenLocaleChanges() {
+    val newValue = Settings.language
+    if ("system" == newValue) {
+        AppCompatDelegate.setApplicationLocales(LocaleListCompat.getEmptyLocaleList())
+    } else {
+        AppCompatDelegate.setApplicationLocales(LocaleListCompat.forLanguageTags(newValue))
+    }
+}

app/src/main/java/com/hippo/ehviewer/ui/settings/AdvancedScreen.kt

@@ -50,12 +50,18 @@ fun AdvancedScreen() {
                 title = stringResource(id = R.string.settings_advanced_dump_logcat),
                 summary = stringResource(id = R.string.settings_advanced_dump_logcat_summary),
             )
-            SimpleMenuPreference(
+            SimpleMenuPreferenceInt(
                 title = stringResource(id = R.string.settings_advanced_read_cache_size),
                 entry = R.array.read_cache_size_entries,
                 entryValueRes = R.array.read_cache_size_entry_values,
                 value = Settings::readCacheSize,
             )
+            SimpleMenuPreference(
+                title = stringResource(id = R.string.settings_advanced_app_language_title),
+                entry = R.array.app_language_entries,
+                entryValueRes = R.array.app_language_entry_values,
+                value = Settings::language,
+            )
         }
     }
 }

app/src/main/java/com/hippo/ehviewer/ui/settings/PreferenceWidgets.kt

@@ -86,7 +86,7 @@ fun HtmlPreference(title: String, summary: AnnotatedString? = null, onClick: ()
 }
 
 @Composable
-fun SimpleMenuPreference(title: String, @ArrayRes entry: Int, @ArrayRes entryValueRes: Int, value: KMutableProperty0<Int>) {
+fun SimpleMenuPreferenceInt(title: String, @ArrayRes entry: Int, @ArrayRes entryValueRes: Int, value: KMutableProperty0<Int>) {
     val entryArray = stringArrayResource(id = entry)
     val valuesArray = stringArrayResource(id = entryValueRes)
     val map = remember {
@@ -98,3 +98,17 @@ fun SimpleMenuPreference(title: String, @ArrayRes entry: Int, @ArrayRes entryVal
     check(entryArray.size == valuesArray.size)
     DropDownPref(title = title, defaultValue = v.toString(), onValueChange = ::set, useSelectedAsSummary = true, entries = map)
 }
+
+@Composable
+fun SimpleMenuPreference(title: String, @ArrayRes entry: Int, @ArrayRes entryValueRes: Int, value: KMutableProperty0<String>) {
+    val entryArray = stringArrayResource(id = entry)
+    val valuesArray = stringArrayResource(id = entryValueRes)
+    val map = remember {
+        val iter = entryArray.iterator()
+        valuesArray.associateWith { iter.next() }
+    }
+    var v by remember { mutableStateOf(value.get()) }
+    fun set(new: String) = value.set(new.also { v = it })
+    check(entryArray.size == valuesArray.size)
+    DropDownPref(title = title, defaultValue = v, onValueChange = ::set, useSelectedAsSummary = true, entries = map)
+}