BF: [iOS11] "Smart [colors] Invert" renders badly in the app

https://github.com/vector-im/riot-ios/issues/1524

- the app does its own dark theme and prevents the OS from automatically revert the colors in the app
- there are 3 choices on iOS11 for the Riot theme: "auto", "light", "dark". "auto" uses the system settings

Riot/AppDelegate.m

@@ -516,6 +516,12 @@ NSString *const kAppDelegateNetworkStatusDidChangeNotification = @"kAppDelegateN
     [self refreshLocalContacts];
     
     _isAppForeground = YES;
+
+    if (@available(iOS 11.0, *))
+    {
+        // Riot has its own dark theme. Prevent iOS from applying its one
+        [[UIApplication sharedApplication] keyWindow].accessibilityIgnoresInvertColors = YES;
+    }
     
     [self handleLaunchAnimation];
 }

Riot/Assets/de.lproj/Vector.strings

@@ -416,8 +416,6 @@
 "auth_email_not_found" = "Fehler beim Senden der E-Mail: Die E-Mail-Adresse wurde nicht gefunden";
 "settings_user_interface" = "BENUTZEROBERFLÄCHE";
 "settings_ui_language" = "Sprache";
-"settings_ui_light_theme" = "Helles Design";
-"settings_ui_dark_theme" = "Dunkles Design";
 // Events formatter
 "event_formatter_member_updates" = "%tu Änderungen der Mitgliedschaft";
 "contacts_user_directory_section" = "NUTZER VERZEICHNIS";

Riot/Assets/en.lproj/Vector.strings

@@ -340,8 +340,12 @@
 //"settings_call_invitations" = "Call invitations";
 
 "settings_ui_language" = "Language";
-"settings_ui_light_theme" = "Light theme";
-"settings_ui_dark_theme" = "Dark theme";
+"settings_ui_theme" = "Theme";
+"settings_ui_theme_auto" = "Auto";
+"settings_ui_theme_light" = "Light";
+"settings_ui_theme_dark" = "Dark";
+"settings_ui_theme_picker_title" = "Select a theme";
+"settings_ui_theme_picker_message" = "\"Auto\" uses your device \"Invert Colours\" settings";
 
 "settings_unignore_user" = "Show all messages from %@?";
 

Riot/Assets/fr.lproj/Vector.strings

@@ -417,8 +417,12 @@
 "auth_phone_in_use" = "Ce numéro de téléphone est déjà utilisé";
 "auth_email_not_found" = "Échec lors de l'envoi de l'e-mail : Cette adresse e-mail n'a pas pu être trouvée";
 "settings_ui_language" = "Langue";
-"settings_ui_light_theme" = "Thème clair";
-"settings_ui_dark_theme" = "Thème sombre";
+"settings_ui_theme" = "Thème";
+"settings_ui_theme_auto" = "Auto";
+"settings_ui_theme_light" = "Clair";
+"settings_ui_theme_dark" = "Sombre";
+"settings_ui_theme_picker_title" = "Selectionnez un thème";
+"settings_ui_theme_picker_message" = "\"Auto\" utilise le paramètre \"Inverser les couleurs\" de votre appareil";
 "collapse" = "réduire";
 "auth_untrusted_id_server" = "Le serveur d'identité n'est pas fiable";
 "settings_user_interface" = "INTERFACE UTILISATEUR";

Riot/Assets/nl.lproj/Vector.strings

@@ -440,8 +440,6 @@
 "contacts_user_directory_offline_section" = "GEBRUIKERSADRESBOEK (offline)";
 "settings_user_interface" = "GEBRUIKERSINTERFACE";
 "settings_ui_language" = "Taal";
-"settings_ui_light_theme" = "Lichte thema";
-"settings_ui_dark_theme" = "Donkere thema";
 // Read Receipts
 "read_receipts_list" = "Leesbewijzen Lijst";
 "receipt_status_read" = "Lees: ";

Riot/Assets/ru.lproj/Vector.strings

@@ -262,8 +262,6 @@
 "settings_global_settings_info" = "Глобальные настройки уведомлений доступны в вашем %@ веб-клиенте";
 "settings_on_denied_notification" = "Уведомления для %@ запрещены, пожалуйста, разрешите их в настройках вашего устройства";
 "settings_ui_language" = "Язык";
-"settings_ui_light_theme" = "Светлая тема";
-"settings_ui_dark_theme" = "Темная тема";
 "settings_unignore_user" = "Показать все сообщения от %@?";
 "settings_labs_e2e_encryption" = "Сквозное шифрование";
 "settings_labs_e2e_encryption_prompt_message" = "Чтобы завершить настройку шифрования, вы должны войти в систему еще раз.";

Riot/Utils/RiotDesignValues.m

@@ -112,8 +112,10 @@ UIColor *kRiotDesignSearchBarTintColor = nil;
     // Observe user interface theme change.
     [[NSUserDefaults standardUserDefaults] addObserver:[RiotDesignValues sharedInstance] forKeyPath:@"userInterfaceTheme" options:0 context:nil];
     [[RiotDesignValues sharedInstance] userInterfaceThemeDidChange];
-}
 
+    // Observe "Invert Colours" settings changes (available since iOS 11)
+    [[NSNotificationCenter defaultCenter] addObserver:[RiotDesignValues sharedInstance] selector:@selector(accessibilityInvertColorsStatusDidChange) name:UIAccessibilityInvertColorsStatusDidChangeNotification object:nil];
+}
 
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
 {
@@ -123,10 +125,25 @@ UIColor *kRiotDesignSearchBarTintColor = nil;
     }
 }
 
+- (void)accessibilityInvertColorsStatusDidChange
+{
+    // Refresh the theme only for "auto"
+    NSString *theme = [[NSUserDefaults standardUserDefaults] stringForKey:@"userInterfaceTheme"];
+    if (!theme || [theme isEqualToString:@"auto"])
+    {
+        [self userInterfaceThemeDidChange];
+    }
+}
+
 - (void)userInterfaceThemeDidChange
 {
-    // Retrieve the current selected theme ("light" if none).
+    // Retrieve the current selected theme ("light" if none. "auto" is used as default from iOS 11).
     NSString *theme = [[NSUserDefaults standardUserDefaults] stringForKey:@"userInterfaceTheme"];
+
+    if (!theme || [theme isEqualToString:@"auto"])
+    {
+        theme = UIAccessibilityIsInvertColorsEnabled() ? @"dark" : @"light";
+    }
     
     // Currently only 2 themes is supported
     if ([theme isEqualToString:@"dark"])

Riot/ViewController/SettingsViewController.m

@@ -1695,36 +1695,39 @@ typedef void (^blockSettingsViewController_onReadyToDestroy)();
         }
         else if (row == USER_INTERFACE_THEME_INDEX)
         {
-            uiThemeCell = [tableView dequeueReusableCellWithIdentifier:[TableViewCellWithCheckBoxes defaultReuseIdentifier] forIndexPath:indexPath];
-            
-            uiThemeCell.mainContainerLeadingConstraint.constant = uiThemeCell.separatorInset.left;
-            
-            uiThemeCell.checkBoxesNumber = 2;
-            
-            uiThemeCell.allowsMultipleSelection = NO;
-            uiThemeCell.delegate = self;
-            
-            NSArray *labels = uiThemeCell.labels;
-            UILabel *label;
-            label = labels[0];
-            label.textColor = kRiotPrimaryTextColor;
-            label.text = NSLocalizedStringFromTable(@"settings_ui_light_theme", @"Vector", nil);
-            label = labels[1];
-            label.textColor = kRiotPrimaryTextColor;
-            label.text = NSLocalizedStringFromTable(@"settings_ui_dark_theme", @"Vector", nil);
-            
-            NSString *selectedTheme = [[NSUserDefaults standardUserDefaults] stringForKey:@"userInterfaceTheme"];            
-            if (selectedTheme && [selectedTheme isEqualToString:@"dark"])
+            cell = [tableView dequeueReusableCellWithIdentifier:kSettingsViewControllerPhoneBookCountryCellId];
+            if (!cell)
             {
-                [uiThemeCell setCheckBoxValue:YES atIndex:1];
+                cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:kSettingsViewControllerPhoneBookCountryCellId];
             }
-            else
+
+            NSString *theme = [[NSUserDefaults standardUserDefaults] stringForKey:@"userInterfaceTheme"];
+            if (!theme)
             {
-                // Consider the light theme by default.
-                [uiThemeCell setCheckBoxValue:YES atIndex:0];
+                if (@available(iOS 11.0, *))
+                {
+                    // "auto" is used the default value from iOS 11
+                    theme = @"auto";
+                }
+                else
+                {
+                    // Use "light" for older version
+                    theme = @"light";
+                }
             }
-            
-            cell = uiThemeCell;
+
+            theme = [NSString stringWithFormat:@"settings_ui_theme_%@", theme];
+            NSString *i18nTheme = NSLocalizedStringFromTable(theme,
+                                                              @"Vector",
+                                                             nil);
+
+            cell.textLabel.textColor = kRiotPrimaryTextColor;
+
+            cell.textLabel.text = NSLocalizedStringFromTable(@"settings_ui_theme", @"Vector", nil);
+            cell.detailTextLabel.text = i18nTheme;
+
+            cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
+            cell.selectionStyle = UITableViewCellSelectionStyleDefault;
         }
     }
     else if (section == SETTINGS_SECTION_IGNORED_USERS_INDEX)
@@ -2270,6 +2273,10 @@ typedef void (^blockSettingsViewController_onReadyToDestroy)();
                 languagePickerViewController.delegate = self;
                 [self pushViewController:languagePickerViewController];
             }
+            else if (row == USER_INTERFACE_THEME_INDEX)
+            {
+                [self showThemePicker];
+            }
         }
         else if (section == SETTINGS_SECTION_IGNORED_USERS_INDEX)
         {
@@ -3430,6 +3437,87 @@ typedef void (^blockSettingsViewController_onReadyToDestroy)();
     }
 }
 
+- (void)showThemePicker
+{
+    __weak typeof(self) weakSelf = self;
+
+    __block UIAlertAction *autoAction, *lightAction, *darkAction;
+    NSString *themePickerMessage;
+
+    void (^actionBlock)(UIAlertAction *action) = ^(UIAlertAction * action) {
+
+        if (weakSelf)
+        {
+            typeof(self) self = weakSelf;
+
+            NSString *newTheme;
+            if (action == autoAction)
+            {
+                newTheme = @"auto";
+            }
+            else  if (action == lightAction)
+            {
+                newTheme = @"light";
+            }
+            else if (action == darkAction)
+            {
+                newTheme = @"dark";
+            }
+
+            NSString *theme = [[NSUserDefaults standardUserDefaults] stringForKey:@"userInterfaceTheme"];
+            if (newTheme && ![newTheme isEqualToString:theme])
+            {
+                // Clear fake Riot Avatars based on the previous theme.
+                [AvatarGenerator clear];
+
+                // The user wants to select this theme
+                [[NSUserDefaults standardUserDefaults] setObject:newTheme forKey:@"userInterfaceTheme"];
+                [[NSUserDefaults standardUserDefaults] synchronize];
+
+                [self.tableView reloadData];
+            }
+        }
+    };
+
+    if (@available(iOS 11.0, *))
+    {
+        // Show "auto" only from iOS 11
+        autoAction = [UIAlertAction actionWithTitle:NSLocalizedStringFromTable(@"settings_ui_theme_auto", @"Vector", nil)
+                                              style:UIAlertActionStyleDefault
+                                            handler:actionBlock];
+
+        // Explain what is "auto"
+        themePickerMessage = NSLocalizedStringFromTable(@"settings_ui_theme_picker_message", @"Vector", nil);
+    }
+
+    lightAction = [UIAlertAction actionWithTitle:NSLocalizedStringFromTable(@"settings_ui_theme_light", @"Vector", nil)
+                                          style:UIAlertActionStyleDefault
+                                        handler:actionBlock];
+
+    darkAction = [UIAlertAction actionWithTitle:NSLocalizedStringFromTable(@"settings_ui_theme_dark", @"Vector", nil)
+                                           style:UIAlertActionStyleDefault
+                                         handler:actionBlock];
+
+    // Ask the user the kind of the call: voice or video?
+    UIAlertController *themePicker = [UIAlertController alertControllerWithTitle:NSLocalizedStringFromTable(@"settings_ui_theme_picker_title", @"Vector", nil)
+                                                                         message:themePickerMessage
+                                                                  preferredStyle:UIAlertControllerStyleActionSheet];
+
+    if (autoAction)
+    {
+        [themePicker addAction:autoAction];
+    }
+    [themePicker addAction:lightAction];
+    [themePicker addAction:darkAction];
+
+    // Cancel button
+    [themePicker addAction:[UIAlertAction actionWithTitle:[NSBundle mxk_localizedStringForKey:@"cancel"]
+                                                        style:UIAlertActionStyleDefault
+                                                      handler:nil]];
+
+    [self presentViewController:themePicker animated:YES completion:nil];
+}
+
 #pragma mark - MediaPickerViewController Delegate
 
 - (void)dismissMediaPicker
@@ -3773,21 +3861,6 @@ typedef void (^blockSettingsViewController_onReadyToDestroy)();
 
 - (void)tableViewCellWithCheckBoxes:(TableViewCellWithCheckBoxes *)tableViewCellWithCheckBoxes didTapOnCheckBoxAtIndex:(NSUInteger)index
 {
-    if (tableViewCellWithCheckBoxes == uiThemeCell)
-    {
-        NSString *theme = (index == 0) ? @"light" : @"dark";
-        BOOL isCurrentlySelected = [uiThemeCell checkBoxValueAtIndex:index];
-        
-        if (!isCurrentlySelected)
-        {
-            // Clear fake Riot Avatars based on the previous theme.
-            [AvatarGenerator clear];
-            
-            // The user wants to select this theme
-            [[NSUserDefaults standardUserDefaults] setObject:theme forKey:@"userInterfaceTheme"];
-            [[NSUserDefaults standardUserDefaults] synchronize];
-        }
-    }
 }
 
 @end