Open Notification Center programmatically on OS X - macos

Question

Is there a way to open Notification Center on OS X from a Cocoa app?
We tried launching the Notification Center app, but that doesn't work.
Our app is not sandboxed, so we can do whatever is required.

Answer 1

You can open it using ScriptingBridge, but it's not an official API, so it might break someday.
It's a bit odd, but this only works with sandboxed apps. If your app is not sandboxed, you need Accessibility access.
1. Generate Header file
Open Terminal and run the following commands:
cd ~/Desktop/
sdef /System/Library/CoreServices/System\ Events.app | sdp -fh --basename SystemEvents
Copy the file "SystemEvents.h" from your Desktop into your project.
Xcode will show some errors or warnings for a few lines in this file. Just remove these lines.
2. Import ScriptingBridge framework and generated header file.
#import <ScriptingBridge/ScriptingBridge.h>
and
#import "SystemEvents.h"
3. Add code
SystemEventsApplication *systemEventsApp = (SystemEventsApplication *)[[SBApplication alloc] initWithBundleIdentifier:#"com.apple.systemevents"];
SystemEventsApplicationProcess *sysUIServer = [systemEventsApp.applicationProcesses objectWithName:#"SystemUIServer"];
SystemEventsMenuBarItem *item = nil;
for (SystemEventsMenuBar *menuBar in sysUIServer.menuBars) {
item = [menuBar.menuBarItems objectWithName:#"Notification Center"];
if (item != nil && [item.name isEqualToString:#"Notification Center"])
break;
}
[item clickAt:nil];
You can also replace line 4-9 with this code, if you're sure the menu bars won't change in the future:
SystemEventsMenuBarItem *item = [[[sysUIServer.menuBars objectAtLocation:#2] menuBarItems] objectWithName:#"Notification Center"];
4. Add temporary exception for sandbox
Open your projects .entitlements file and add "com.apple.security.temporary-exception.apple-events" as an array. Add "com.apple.systemevents" as String.
Switching to Today view
This requires your app to have Accessibility access, so it won't work in sandboxed apps. You can simply call this script instead of using ScriptingBridge:
tell application "System Events"
click menu bar item "Notification Center" of menu bar 2 of application process "SystemUIServer"
click radio button "Today" of radio group 1 of window "NotificationTableWindow" of application process "NotificationCenter"
end tell

Answer 2

No, unfortunately there is no support for opening the Notification Center. Supposedly because it wouldn't be annoying for the user to have it open without them wanting it to open