I want to create a Safari share extension for my main app, and I just realized that there are already many of share extensions when I open the safari share activity, while I didn't install any extensions from app store my self. So, is that a share extension will be atomically installed with your main app?
Thanks in advance for answering!
Extensions, including share extensions, will be installed on the device at the time the user downloads your main application whose bundle includes the extension. In other words, if a user downloads your app, they'll also get your extension.
Note: Extensions are not enabled by default, so users will have to enable them manually after install.
Edit
Info on extensions, including where they live with respect to your app binary and how they are delivered to users' devices, is here. This excerpt is from that page of the docs:
An app extension is different from an app. Although you must use an app to contain and deliver your extensions, each extension is a separate binary that runs independent of the app used to deliver it.
You create an app extension by adding a new target to an app. As with any target, an extension target specifies settings and files that combine to build a product within your app project. You can add multiple extension targets to a single app (an app that contains one or more extensions is called a containing app).
The best way to start developing an app extension is to use one of the templates that Xcode provides for each extension point on both platforms. Each template includes extension point–specific implementation files and settings, and produces a separate binary that gets added to your containing app’s bundle.
To distribute app extensions to users, you submit a containing app to the App Store. When a user installs your containing app, the extensions it contains are also installed.
After installing an app extension, a user must take action to enable it. Often, users can enable an extension within the context of their current task. If your extension is a Today widget, for example, users can edit the Today view in Notification Center to enable your extension. In other cases, users can use Settings (in iOS) or System Preferences (in OS X) to enable and manage the extensions they install.
