feat: Infinite Scrolling Optimization and Swipe-to-Refresh for Notifications Inbox Screen

core/src/main/java/org/openedx/core/presentation/global/FullScreenState.kt

@@ -0,0 +1,31 @@
+package org.openedx.core.presentation.global
+
+import androidx.annotation.StringRes
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.outlined.PriorityHigh
+import androidx.compose.material.icons.outlined.SignalWifiStatusbarConnectedNoInternet4
+import androidx.compose.ui.graphics.vector.ImageVector
+import org.openedx.core.R
+
+open class FullScreenState(
+    val imageVector: ImageVector,
+    @StringRes val titleResId: Int,
+    @StringRes val descriptionResId: Int,
+    @StringRes val actionButtonResId: Int? = null,
+) {
+    companion object {
+        val NetworkError = FullScreenState(
+            imageVector = Icons.Outlined.SignalWifiStatusbarConnectedNoInternet4,
+            titleResId = R.string.core_no_internet_connection,
+            descriptionResId = R.string.core_no_internet_connection_description,
+            actionButtonResId = R.string.core_reload
+        )
+
+        val ServerError = FullScreenState(
+            imageVector = Icons.Outlined.PriorityHigh,
+            titleResId = R.string.core_server_error,
+            descriptionResId = R.string.core_server_error_description,
+            actionButtonResId = R.string.core_reload
+        )
+    }
+}

core/src/main/java/org/openedx/core/ui/ComposeCommon.kt

@@ -68,7 +68,6 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
-import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.drawWithContent
@@ -102,6 +101,9 @@ import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.text.withStyle
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.tooling.preview.PreviewLightDark
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.TextUnit
 import androidx.compose.ui.unit.dp
@@ -120,6 +122,7 @@ import org.openedx.core.extension.tagId
 import org.openedx.core.extension.takeIfNotEmpty
 import org.openedx.core.extension.toastMessage
 import org.openedx.core.presentation.global.ErrorType
+import org.openedx.core.presentation.global.FullScreenState
 import org.openedx.core.ui.theme.OpenEdXTheme
 import org.openedx.core.ui.theme.appColors
 import org.openedx.core.ui.theme.appShapes
@@ -221,7 +224,6 @@ fun Toolbar(
     }
 }
 
-@OptIn(ExperimentalComposeUiApi::class)
 @Composable
 fun SearchBar(
     modifier: Modifier,
@@ -321,7 +323,6 @@ fun SearchBar(
     )
 }
 
-@OptIn(ExperimentalComposeUiApi::class)
 @Composable
 fun SearchBarStateless(
     modifier: Modifier,
@@ -1464,6 +1465,67 @@ private fun RoundTab(
     }
 }
 
+@Composable
+fun FullScreenStateView(
+    modifier: Modifier = Modifier,
+    state: FullScreenState,
+    onAction: () -> Unit = { },
+) {
+    Column(
+        modifier = modifier
+            .fillMaxSize()
+            .background(MaterialTheme.appColors.background)
+            .padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Box(
+            modifier = Modifier
+                .clip(CircleShape)
+                .size(62.dp)
+                .background(MaterialTheme.appColors.primaryCardCautionBackground)
+                .padding(4.dp),
+        ) {
+            Icon(
+                modifier = Modifier
+                    .size(42.dp)
+                    .align(Alignment.Center),
+                imageVector = state.imageVector,
+                contentDescription = null,
+                tint = MaterialTheme.appColors.onSurface
+            )
+        }
+        Spacer(modifier = Modifier.height(12.dp))
+
+        Text(
+            text = stringResource(id = state.titleResId),
+            style = MaterialTheme.appTypography.titleLarge,
+            color = MaterialTheme.appColors.textPrimary,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(modifier = Modifier.height(12.dp))
+
+        Text(
+            text = stringResource(id = state.descriptionResId),
+            style = MaterialTheme.appTypography.bodyLarge,
+            color = MaterialTheme.appColors.textPrimary,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(modifier = Modifier.height(12.dp))
+
+        state.actionButtonResId?.let {
+            OpenEdXPrimaryButton(
+                modifier = Modifier
+                    .widthIn(Dp.Unspecified, 162.dp),
+                text = stringResource(id = it),
+                textColor = MaterialTheme.appColors.secondaryButtonText,
+                backgroundColor = MaterialTheme.appColors.secondaryButtonBackground,
+                onClick = onAction,
+            )
+        }
+    }
+}
+
 @Preview
 @Composable
 private fun StaticSearchBarPreview() {
@@ -1612,3 +1674,20 @@ private fun PreviewNoContentScreen() {
         )
     }
 }
+
+private class FullScreenStatePreviewParameterProvider : PreviewParameterProvider<FullScreenState> {
+    override val values = sequenceOf(
+        FullScreenState.NetworkError,
+        FullScreenState.ServerError,
+    )
+}
+
+@PreviewLightDark
+@Composable
+private fun FullScreenStatePreview(
+    @PreviewParameter(FullScreenStatePreviewParameterProvider::class) state: FullScreenState,
+) {
+    OpenEdXTheme {
+        FullScreenStateView(state = state)
+    }
+}

core/src/main/java/org/openedx/core/ui/ComposeExtensions.kt

@@ -88,9 +88,39 @@ fun LazyGridState.shouldLoadMore(rememberedIndex: MutableState<Int>, threshold:
     return false
 }
 
-fun LazyListState.shouldLoadMore(threshold: Int): Boolean {
-    val lastVisibleIndex = layoutInfo.visibleItemsInfo.lastOrNull()?.index ?: return false
-    return lastVisibleIndex >= layoutInfo.totalItemsCount - 1 - threshold
+/**
+ * Tracks changes to both the first and last visible item indices and accounts for
+ * edge cases where all items on the current page might fit within the viewport (e.g., due to
+ * dynamic item sizes).
+ *
+ * Triggers a load when:
+ * - The first or last visible item index changes.
+ * - All items fit on the screen (e.g., due to dynamic sizes).
+ *
+ * @param rememberedFirstIndex Tracks the previous first visible item index.
+ * @param rememberedLastIndex Tracks the previous last visible item index.
+ * @param threshold Number of items from the end of the list to trigger loading.
+ * @return `true` if more items should be loaded; `false` otherwise.
+ */
+fun LazyListState.shouldLoadMore(
+    rememberedFirstIndex: MutableState<Int>,
+    rememberedLastIndex: MutableState<Int>,
+    threshold: Int
+): Boolean {
+    val firstVisibleIndex = this.firstVisibleItemIndex
+    val lastVisibleIndex = layoutInfo.visibleItemsInfo.lastOrNull()?.index ?: 0
+    val totalItemsCount = layoutInfo.totalItemsCount
+
+    if (
+        rememberedFirstIndex.value != firstVisibleIndex ||
+        rememberedLastIndex.value != lastVisibleIndex ||
+        (firstVisibleIndex == 0 && lastVisibleIndex == totalItemsCount - 1)
+    ) {
+        rememberedFirstIndex.value = firstVisibleIndex
+        rememberedLastIndex.value = lastVisibleIndex
+        return lastVisibleIndex >= totalItemsCount - 1 - threshold
+    }
+    return false
 }
 
 fun Modifier.statusBarsInset(): Modifier = composed {

core/src/main/res/values/strings.xml

@@ -77,6 +77,8 @@
     <string name="core_thank_you_dialog_negative_description">We received your feedback and will use it to help improve your learning experience going forward. Thank you for sharing!</string>
     <string name="core_no_internet_connection">No internet connection</string>
     <string name="core_no_internet_connection_description">Please connect to the internet to view this content.</string>
+    <string name="core_server_error">Server error</string>
+    <string name="core_server_error_description">Something went wrong on our end. Please try again later.</string>
     <string name="core_try_again">Try Again</string>
     <string name="core_something_went_wrong_description">Something went wrong</string>
     <string name="core_ok" tools:ignore="MissingTranslation">OK</string>

dashboard/src/main/java/org/openedx/learn/presentation/LearnViewModel.kt

@@ -78,8 +78,12 @@ class LearnViewModel(
     private fun checkNotificationCount() {
         if (config.isPushNotificationsEnabled()) {
             viewModelScope.launch(Dispatchers.IO) {
-                val unreadNotifications = pushManager.getUnreadNotificationsCount()
-                _uiState.update { it.copy(hasUnreadNotifications = unreadNotifications > 0) }
+                try {
+                    val unreadNotifications = pushManager.getUnreadNotificationsCount()
+                    _uiState.update { it.copy(hasUnreadNotifications = unreadNotifications > 0) }
+                } catch (e: Exception) {
+                    e.printStackTrace()
+                }
             }
         }
     }

notifications/src/main/java/org/openedx/notifications/presentation/inbox/InboxFullScreenState.kt

@@ -0,0 +1,16 @@
+package org.openedx.notifications.presentation.inbox
+
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.outlined.Notifications
+import org.openedx.core.presentation.global.FullScreenState
+import org.openedx.notifications.R
+
+object InboxFullScreenState {
+    val Empty = FullScreenState(
+        imageVector = Icons.Outlined.Notifications,
+        titleResId = R.string.notifications_no_notifications_yet,
+        descriptionResId = R.string.notifications_no_notifications_yet_description
+    )
+    val NetworkError = FullScreenState.NetworkError
+    val ServerError = FullScreenState.ServerError
+}

notifications/src/main/java/org/openedx/notifications/presentation/inbox/InboxUIState.kt

@@ -1,5 +1,6 @@
 package org.openedx.notifications.presentation.inbox
 
+import org.openedx.core.presentation.global.FullScreenState
 import org.openedx.notifications.domain.model.InboxSection
 import org.openedx.notifications.domain.model.NotificationItem
 
@@ -9,7 +10,9 @@ sealed class InboxUIState {
         val notifications: Map<InboxSection, List<NotificationItem>>,
     ) : InboxUIState()
 
-    data object Empty : InboxUIState()
-    data object Error : InboxUIState()
     data object Loading : InboxUIState()
+
+    data class Fallback(
+        val state: FullScreenState,
+    ) : InboxUIState()
 }