Apps How can I get other apps notifications?

[legitscoper]

I am making app for DIY smartwatch. How can I get notifications from other apps like Messenger, Gmail, Phone call? For example when I will receive it I will send some info by bluetooth

 

[Deleted User]

Your question is slightly confusing, and there's no generalised solution for what you are proposing. Besides some of the things you mention aren't notification services. For instance Gmail is a service which is accessed via an email client i.e. a 'pull request' type of service, not notification.
Can you possibly narrow down how you want your app to receive information, and elaborate on where these notifications are coming from?
If you want to receive information via different types of services, I think you will have to implement specific ways of doing this for each one.