Plug: rewrite placeholder

[danirabbit]

• Use SPDX copyright header
• Don't build in multiple single-use functions
• Remove hard line breaks from placeholder strings
• Remove useless "nothing to do" title
• Add a titlebar to the placeholder
• Check for configurable apps on shown not just when constructed

[danirabbit]

I actually wonder if it's possible to see this screen/if it's worth having this screen since there are entries for settings daemon and "other". Should we just remove this since system settings depends on settings daemon?

[ryonakano]

Should we just remove this since system settings depends on settings daemon?

I personally think we should keep this placeholder even if it would never appear. The backend implementation itself just iterates on installed apps that use notifications and does not add Setting Daemon manually:

https://github.com/elementary/switchboard-plug-notifications/blob/d7f135521c2d24ddb0f431c90ae1ceb280fdfa58/src/Backend/NotifyManager.vala#L31-L48

So I don't think it's guaranteed that Backend.NotifyManager.get_default ().apps is always not a blank HashMap.

since there are entries for settings daemon and "other".

This is a result so I don't think we should do an implementation which assumes that.

[ryonakano]

The issue gone when in case of the main view, but still occurs in case of the placeholder view:

Kooha-2025-08-17-19-19-34.webm

user@elementary-daily:~/work/switchboard-plug-notifications$ git diff
diff --git a/src/Plug.vala b/src/Plug.vala
index e6c75b7..b9c9000 100644
--- a/src/Plug.vala
+++ b/src/Plug.vala
@@ -61,7 +61,8 @@ public class NotificationsPlug : Switchboard.Plug {
     }
 
     public override void shown () {
-        if (Backend.NotifyManager.get_default ().apps.size > 0) {
+        //if (Backend.NotifyManager.get_default ().apps.size > 0) {
+        if (false) {
             stack.visible_child = main_view;
         } else {
             stack.visible_child = placeholder_view;
user@elementary-daily:~/work/switchboard-plug-notifications$ 

[danirabbit]

@ryonakano this might be a bug in Granite.Placeholder. I'd still like to get it merged as is since it's an improvement but I've removed the fixes line