MOBILE-4081 forum: Display selectors if loading discussions fail

Author: dpalou

scripts/langindex.json

@@ -639,6 +639,8 @@
   "addon.mod_forum.erroremptysubject": "forum",
   "addon.mod_forum.errorgetforum": "local_moodlemobileapp",
   "addon.mod_forum.errorgetgroups": "local_moodlemobileapp",
+  "addon.mod_forum.errorloadingsortingorder": "local_moodlemobileapp",
+  "addon.mod_forum.errorloadingsortingorderdetails": "local_moodlemobileapp",
   "addon.mod_forum.errorposttoallgroups": "local_moodlemobileapp",
   "addon.mod_forum.favourites": "forum",
   "addon.mod_forum.favouriteupdated": "forum",

src/addons/mod/forum/classes/forum-discussions-source.ts

@@ -44,6 +44,7 @@ export class AddonModForumDiscussionsSource extends CoreRoutedItemsManagerSource
     groupInfo?: CoreGroupInfo;
     allPartsPermissions?: AddonModForumCanAddDiscussion;
     canAddDiscussionToGroup = true;
+    errorLoadingDiscussions = false;
 
     constructor(courseId: number, cmId: number, discussionsPathPrefix: string) {
         super();
@@ -222,13 +223,27 @@ export class AddonModForumDiscussionsSource extends CoreRoutedItemsManagerSource
             throw new Error('Can\'t load discussions without a forum or selected sort order');
         }
 
-        const response = await AddonModForum.getDiscussions(this.forum.id, {
-            cmId: this.forum.cmid,
-            sortOrder: this.selectedSortOrder.value,
-            page,
-            groupId: this.groupId,
-        });
-        let discussions = response.discussions;
+        let discussions: AddonModForumDiscussion[] = [];
+        let canLoadMore = false;
+        try {
+            const response = await AddonModForum.getDiscussions(this.forum.id, {
+                cmId: this.forum.cmid,
+                sortOrder: this.selectedSortOrder.value,
+                page,
+                groupId: this.groupId,
+            });
+
+            discussions = response.discussions;
+            canLoadMore = response.canLoadMore;
+            this.errorLoadingDiscussions = false;
+        } catch (error) {
+            if (page > 0 || CoreUtils.isWebServiceError(error)) {
+                throw error;
+            }
+
+            // Error loading first discussions, use an empty list.
+            this.errorLoadingDiscussions = true;
+        }
 
         if (this.usesGroups) {
             discussions = await AddonModForum.formatDiscussionsGroups(this.forum.cmid, discussions);
@@ -254,7 +269,7 @@ export class AddonModForumDiscussionsSource extends CoreRoutedItemsManagerSource
             }
         }
 
-        return { discussions, canLoadMore: response.canLoadMore };
+        return { discussions, canLoadMore };
     }
 
     /**

src/addons/mod/forum/components/index/index.html

@@ -54,17 +54,22 @@
         </ion-card>
 
         <ng-container *ngIf="forum">
-            <core-empty-box *ngIf="!discussions || !discussions.hasDiscussions" icon="far-comments"
-                [message]="'addon.mod_forum.forumnodiscussionsyet' | translate">
-            </core-empty-box>
-
-            <div *ngIf="discussions?.hasDiscussions && sortingAvailable && selectedSortOrder" class="ion-text-wrap">
+            <div *ngIf="discussions && sortingAvailable && selectedSortOrder" class="ion-text-wrap">
                 <core-combobox [modalOptions]="sortOrderSelectorModalOptions" listboxId="addon-mod-forum-sort-selector"
                     [label]="('core.sort' | translate)" (onChange)="setSortOrder($event)" [selection]="selectedSortOrder.label | translate"
                     interface="modal">
                 </core-combobox>
             </div>
 
+            <core-empty-box *ngIf="!discussions || (!discussions.hasDiscussions && !errorLoadingDiscussions)" icon="far-comments"
+                [message]="'addon.mod_forum.forumnodiscussionsyet' | translate">
+            </core-empty-box>
+
+            <core-empty-box *ngIf="errorLoadingDiscussions" icon="fas-exclamation-triangle"
+                [message]="'addon.mod_forum.errorloadingsortingorder' | translate">
+                <p>{{ 'addon.mod_forum.errorloadingsortingorderdetails' | translate }}</p>
+            </core-empty-box>
+
             <ion-item *ngFor="let discussion of discussionsItems" class="addon-mod-forum-discussion" detail="true"
                 [lines]="discussion.groupname && 'none'" [attr.aria-current]="discussions?.getItemAriaCurrent(discussion)"
                 (click)="discussions?.select(discussion)" button>

src/addons/mod/forum/components/index/index.ts

@@ -152,6 +152,10 @@ export class AddonModForumIndexComponent extends CoreCourseModuleMainActivityCom
         return !!(this.forum && this.canAddDiscussion && this.discussions?.getSource().canAddDiscussionToGroup);
     }
 
+    get errorLoadingDiscussions(): boolean {
+        return !!this.discussions?.getSource().errorLoadingDiscussions;
+    }
+
     /**
      * Check whether a discussion is online.
      *

src/addons/mod/forum/lang.json

@@ -28,6 +28,8 @@
     "erroremptysubject": "Post subject cannot be empty.",
     "errorgetforum": "Error getting forum data.",
     "errorgetgroups": "Error getting group settings.",
+    "errorloadingsortingorder": "Forum not available in this sorting order",
+    "errorloadingsortingorderdetails": "Try changing the sorting order or going online to view this forum.",
     "errorposttoallgroups": "Could not create new discussion in all groups.",
     "favourites": "Starred",
     "favouriteupdated": "Your star option has been updated.",