Merge pull request #1287 from vector-im/scroll_to_unread_on_rooms_tab_tap

UX Rework - Rooms tab: Tap on the current tab's icon jumps to next un…

Riot/ViewController/MasterTabBarController.m

@@ -674,4 +674,15 @@
     [currentAlert showInViewController:self];
 }
 
+#pragma mark - UITabBarDelegate
+
+- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
+{
+    if (item.tag == TABBAR_ROOMS_INDEX && self.selectedIndex == TABBAR_ROOMS_INDEX)
+    {
+        // Scroll to the next room with missed notifications.
+        [self.roomsViewController scrollToNextRoomWithMissedNotifications];
+    }
+}
+
 @end

Riot/ViewController/RoomsViewController.h

@@ -21,4 +21,10 @@
  */
 @interface RoomsViewController : RecentsViewController
 
+/**
+ Scroll to the potential room with missed notifications which is not visible yet.
+ */
+- (void)scrollToNextRoomWithMissedNotifications;
+
+
 @end

Riot/ViewController/RoomsViewController.m

@@ -125,6 +125,42 @@
     }
 }
 
+#pragma mark - 
+
+- (void)scrollToNextRoomWithMissedNotifications
+{
+    // Check whether the recents data source is correctly configured.
+    if (recentsDataSource.recentsDataSourceMode != RecentsDataSourceModeRooms)
+    {
+        return;
+    }
+    
+    NSIndexPath *lastVisibleIndexPath = self.recentsTableView.indexPathsForVisibleRows.lastObject;
+    if (lastVisibleIndexPath.section == recentsDataSource.conversationSection)
+    {
+        // Look for the next room with missed notifications.
+        NSIndexPath *nextIndexPath = [NSIndexPath indexPathForRow:lastVisibleIndexPath.row + 1 inSection:recentsDataSource.conversationSection];
+        id<MXKRecentCellDataStoring> cellData = [recentsDataSource cellDataAtIndexPath:nextIndexPath];
+        
+        while (cellData)
+        {
+            if (cellData.notificationCount)
+            {
+                [self.recentsTableView scrollToRowAtIndexPath:nextIndexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
+                break;
+            }
+            nextIndexPath = [NSIndexPath indexPathForRow:nextIndexPath.row + 1 inSection:recentsDataSource.conversationSection];
+            cellData = [recentsDataSource cellDataAtIndexPath:nextIndexPath];
+        }
+        
+        if (!cellData)
+        {
+            // Scroll back to the top.
+            [self.recentsTableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:recentsDataSource.conversationSection] atScrollPosition:UITableViewScrollPositionTop animated:YES];
+        }
+    }
+}
+
 #pragma mark - Navigation
 
 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender