You can use cards to show screens from another app inline in your app. For example, users can tap a PDF in an email message and view the PDF in a previewer instead of having to switch apps. Cards help users to complete a full task in your app using capabilities that are already provided to you. Choose from the following three types of cards:
Viewing content such as open pictures, emails, and documents, or play audio and video files
Users can open a previewer by tapping a file type that you've added previewer support to.
A previewer transitions in from the right to the left of the screen.
Include an action bar with a back button and applicable actions on the previewer.
Creating content such as a new contact, calendar entry, or status update.
A composer transitions in from the right to the left of the screen.
Use a sheet pattern to lay out the screen.
Selecting content such as adding recipients in an address field or adding attachments to a message.
A picker transitions in from the right to the left of the screen.
Use a sheet to lay out the screen. You can also include pickers in a composer.