You can use cards to show screens from another app in your app. For example, users can tap a PDF attached to an email message and view it in a previewer instead of switching apps. By using cards in your app, you let users complete a task entirely in your app. Choose from the following three types of cards:
Users open a previewer by tapping a file type that you added previewer support to. A previewer transitions in from the right side of the screen to the left. Include an action bar with a button and applicable actions on the previewer.
Displaying content such as photos, emails, and documents, or play audio and video files.
A composer transitions in from the right to the left of the screen. Use a sheet pattern to lay out the screen.
Creating content such as a new contact, calendar entry, or status update.
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.
Selecting content, such as adding recipients in an address field or adding attachments to a message.