- creates a generic sealed interface for compose ui state

- updates compose view model to use simple states

Author: Williamrai

app/src/main/java/org/wikipedia/language/addlanguages/AddLanguagesListActivity.kt

@@ -27,7 +27,7 @@ class AddLanguagesListActivity : BaseActivity() {
                 LanguagesListScreen(
                     modifier = Modifier
                         .fillMaxSize(),
-                    languageListUiState = uiState,
+                    uiState = uiState,
                     onBackButtonClick = {
                         finish()
                     },

app/src/main/java/org/wikipedia/language/addlanguages/AddLanguagesListScreen.kt

@@ -44,11 +44,12 @@ import org.wikipedia.compose.components.error.ComposeWikiErrorParentView
 import org.wikipedia.compose.components.error.WikiErrorClickEvents
 import org.wikipedia.compose.theme.WikipediaTheme
 import org.wikipedia.util.StringUtil
+import org.wikipedia.util.UiState
 
 @Composable
 fun LanguagesListScreen(
     modifier: Modifier = Modifier,
-    languageListUiState: LanguageListUiState,
+    uiState: UiState<List<LanguageListItem>>,
     onBackButtonClick: () -> Unit,
     onSearchQueryChange: (String) -> Unit,
     onListItemClick: (code: String) -> Unit,
@@ -82,40 +83,41 @@ fun LanguagesListScreen(
         },
         containerColor = WikipediaTheme.colors.paperColor
     ) { paddingValues ->
-        when (languageListUiState) {
-            is LanguageListUiState.Error -> {
+        when (uiState) {
+            UiState.Loading -> {
                 Box(
                     modifier = modifier
                         .fillMaxSize()
                         .padding(paddingValues)
-                        // Add bottom padding when keyboard is visible for android 15 and above
-                        .padding(bottom = if (isKeyboardVisible) imeHeight else 0.dp),
-                    contentAlignment = Alignment.Center
                 ) {
-                    ComposeWikiErrorParentView(
+                    CircularProgressIndicator(
                         modifier = Modifier
-                            .fillMaxWidth(),
-                        caught = languageListUiState.error,
-                        errorClickEvents = wikiErrorClickEvents
+                            .align(Alignment.BottomEnd)
+                            .padding(24.dp),
+                        color = WikipediaTheme.colors.progressiveColor
                     )
                 }
             }
-            is LanguageListUiState.Loading -> {
+            is UiState.Error -> {
                 Box(
                     modifier = modifier
                         .fillMaxSize()
                         .padding(paddingValues)
+                        // Add bottom padding when keyboard is visible for android 15 and above
+                        .padding(bottom = if (isKeyboardVisible) imeHeight else 0.dp),
+                    contentAlignment = Alignment.Center
                 ) {
-                    CircularProgressIndicator(
+                    ComposeWikiErrorParentView(
                         modifier = Modifier
-                            .align(Alignment.BottomEnd)
-                            .padding(24.dp),
-                        color = WikipediaTheme.colors.progressiveColor
+                            .fillMaxWidth(),
+                        caught = uiState.error,
+                        errorClickEvents = wikiErrorClickEvents
                     )
                 }
             }
-            is LanguageListUiState.Success -> {
-                if (languageListUiState.languagesItems.isEmpty()) {
+            is UiState.Success -> {
+                val languagesItems = uiState.data
+                if (languagesItems.isEmpty()) {
                     Box(
                         modifier = modifier
                             .fillMaxSize()
@@ -132,12 +134,13 @@ fun LanguagesListScreen(
                     }
                     return@Scaffold
                 }
+
                 LazyColumn(
                     modifier = modifier
                         .fillMaxSize()
                         .padding(paddingValues),
                 ) {
-                    items(languageListUiState.languagesItems) { languageItem ->
+                    items(languagesItems) { languageItem ->
                         if (languageItem.headerText.isNotEmpty()) {
                             ListHeader(
                                 modifier = Modifier

app/src/main/java/org/wikipedia/language/addlanguages/AddLanguagesViewModel.kt

@@ -5,7 +5,6 @@ import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.CoroutineExceptionHandler
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
@@ -14,6 +13,7 @@ import org.wikipedia.R
 import org.wikipedia.WikipediaApp
 import org.wikipedia.dataclient.ServiceFactory
 import org.wikipedia.dataclient.mwapi.SiteMatrix
+import org.wikipedia.util.UiState
 import org.wikipedia.util.log.L
 
 class AddLanguagesViewModel : ViewModel() {
@@ -25,12 +25,12 @@ class AddLanguagesViewModel : ViewModel() {
     private val _siteInfoList = MutableStateFlow<List<SiteMatrix.SiteInfo>>(emptyList())
 
     // UI state exposed to Compose
-    private val _uiState = MutableStateFlow<LanguageListUiState>(LanguageListUiState.Loading)
-    val uiState: StateFlow<LanguageListUiState> = _uiState.asStateFlow()
+    private val _uiState = MutableStateFlow<UiState<List<LanguageListItem>>>(UiState.Loading)
+    val uiState = _uiState.asStateFlow()
 
     private val handler = CoroutineExceptionHandler { _, throwable ->
         L.e(throwable)
-        _uiState.value = LanguageListUiState.Error(throwable)
+        _uiState.value = UiState.Error(throwable)
     }
 
     private var fetchJob: Job? = null
@@ -43,50 +43,31 @@ class AddLanguagesViewModel : ViewModel() {
         fetchJob?.cancel()
 
         // Set to loading state
-        _uiState.value = LanguageListUiState.Loading
+        _uiState.value = UiState.Loading
 
         // fetch site matrix
         fetchJob = viewModelScope.launch(handler) {
-            _uiState.value = LanguageListUiState.Loading
+            _uiState.value = UiState.Loading
             val siteMatrix = ServiceFactory.get(WikipediaApp.instance.wikiSite).getSiteMatrix()
             val sites = SiteMatrix.getSites(siteMatrix)
             _siteInfoList.value = sites
 
             // isActive checks if the job is still active
             // does not update the list if the coroutine has been cancelled
             if (isActive) {
-                updateSearchTerm(getCurrentSearchTerm(), siteInfoAvailable = true)
+                updateSearchTerm("")
             }
         }
     }
 
-    fun updateSearchTerm(term: String, siteInfoAvailable: Boolean = isSiteInfoLoaded()) {
+    fun updateSearchTerm(term: String) {
         viewModelScope.launch {
-            _uiState.value = LanguageListUiState.Success(
-                searchTerm = term,
-                languagesItems = getFilteredLanguageList(term, siteInfoAvailable),
-                isSiteInfoLoaded = siteInfoAvailable
-            )
-        }
-    }
-
-    private fun isSiteInfoLoaded(): Boolean {
-        return when (val state = _uiState.value) {
-            is LanguageListUiState.Success -> state.isSiteInfoLoaded
-            else -> false
-        }
-    }
-
-    private fun getCurrentSearchTerm(): String {
-        return when (val state = _uiState.value) {
-            is LanguageListUiState.Success -> state.searchTerm
-            else -> ""
+            _uiState.value = UiState.Success(getFilteredLanguageList(term))
         }
     }
 
     private fun getFilteredLanguageList(
         searchTerm: String,
-        siteInfoAvailable: Boolean
     ): List<LanguageListItem> {
         val results = mutableListOf<LanguageListItem>()
         val filter = StringUtils.stripAccents(searchTerm)
@@ -95,16 +76,14 @@ class AddLanguagesViewModel : ViewModel() {
             filter,
             suggestedLanguageCodes,
             WikipediaApp.instance.getString(R.string.languages_list_suggested_text),
-            results,
-            siteInfoAvailable
+            results
         )
 
         addFilteredLanguageListItems(
             filter,
             nonSuggestedLanguageCodes,
             WikipediaApp.instance.getString(R.string.languages_list_all_text),
-            results,
-            siteInfoAvailable
+            results
         )
 
         return results
@@ -115,7 +94,6 @@ class AddLanguagesViewModel : ViewModel() {
         codes: List<String>,
         headerText: String,
         results: MutableList<LanguageListItem>,
-        siteInfoAvailable: Boolean
     ) {
         var first = true
         for (code in codes) {
@@ -124,9 +102,7 @@ class AddLanguagesViewModel : ViewModel() {
             )
 
             // Only attempt to get canonical name if the site is available
-            val canonicalName = if (siteInfoAvailable) {
-                StringUtils.stripAccents(getCanonicalName(code))
-            } else ""
+            val canonicalName = StringUtils.stripAccents(getCanonicalName(code))
 
             if (filter.isEmpty() || code.contains(filter, true) ||
                 localizedName.contains(filter, true) ||
@@ -163,13 +139,3 @@ data class LanguageListItem(
     val canonicalName: String = "",
     val headerText: String = "",
 )
-
-sealed interface LanguageListUiState {
-    data object Loading : LanguageListUiState
-    data class Error(val error: Throwable) : LanguageListUiState
-    data class Success(
-        val searchTerm: String,
-        val languagesItems: List<LanguageListItem> = emptyList(),
-        val isSiteInfoLoaded: Boolean = false
-    ) : LanguageListUiState
-}

app/src/main/java/org/wikipedia/util/Resource.kt

@@ -5,3 +5,9 @@ open class Resource<T> {
     class Success<T>(val data: T) : Resource<T>()
     class Error<T>(val throwable: Throwable) : Resource<T>()
 }
+
+sealed interface UiState<out T> {
+    data object Loading : UiState<Nothing>
+    data class Success<T>(val data: T) : UiState<T>
+    data class Error(val error: Throwable) : UiState<Nothing>
+}