Prepare Dark Theme

Observe user interface theme change.

https://github.com/vector-im/riot-meta/issues/22

Riot/ViewController/RoomSettingsViewController.m

@@ -147,6 +147,9 @@ NSString *const kRoomSettingsAdvancedE2eEnabledCellViewIdentifier = @"kRoomSetti
     
     // A copy of the banned members
     NSArray<MXRoomMember*> *bannedMembers;
+    
+    // Observe kRiotDesignValuesDidChangeThemeNotification to handle user interface theme change.
+    id kRiotDesignValuesDidChangeThemeNotificationObserver;
 }
 @end
 
@@ -159,7 +162,6 @@ NSString *const kRoomSettingsAdvancedE2eEnabledCellViewIdentifier = @"kRoomSetti
     _selectedRoomSettingsField = RoomSettingsViewControllerFieldNone;
     
     // Setup `MXKViewControllerHandling` properties
-    self.defaultBarTintColor = kRiotNavBarTintColor;
     self.enableBarTintColorStatusChange = NO;
     self.rageShakeManager = [RageShakeManager sharedManager];
 }
@@ -232,6 +234,19 @@ NSString *const kRoomSettingsAdvancedE2eEnabledCellViewIdentifier = @"kRoomSetti
     self.tableView.estimatedRowHeight = 44;
     
     [self setNavBarButtons];
+    
+    // Observe user interface theme change.
+    kRiotDesignValuesDidChangeThemeNotificationObserver = [[NSNotificationCenter defaultCenter] addObserverForName:kRiotDesignValuesDidChangeThemeNotification object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *notif) {
+        
+        [self userInterfaceThemeDidChange];
+        
+    }];
+    [self userInterfaceThemeDidChange];
+}
+
+- (void)userInterfaceThemeDidChange
+{
+    self.defaultBarTintColor = kRiotSecondaryBgColor;
 }
 
 - (void)viewWillAppear:(BOOL)animated
@@ -334,6 +349,12 @@ NSString *const kRoomSettingsAdvancedE2eEnabledCellViewIdentifier = @"kRoomSetti
         actualDirectoryVisibilityRequest = nil;
     }
     
+    if (kRiotDesignValuesDidChangeThemeNotificationObserver)
+    {
+        [[NSNotificationCenter defaultCenter] removeObserver:kRiotDesignValuesDidChangeThemeNotificationObserver];
+        kRiotDesignValuesDidChangeThemeNotificationObserver = nil;
+    }
+    
     if (appDelegateDidTapStatusBarNotificationObserver)
     {
         [[NSNotificationCenter defaultCenter] removeObserver:appDelegateDidTapStatusBarNotificationObserver];