11.3. Roll Your Own: Browsers, Maps, and Email

As you've seen, your app's talents should reflect an undistracted focus on its primary task, and you should bring a jaded eye to feature-creep additions that aren't strictly necessary to that mission. But don't allow tunnel vision to blind you to secondary features that are such natural extensions of your app's main gig that their absence grates. The usual suspects here are browsing the web, exploring maps, and sending email. When roundtrips to Safari, Maps, and Mail begin to pile up, it's best to bring those features in-house.

The main mission of a Twitter app, for example, is to let you read and post status updates, but those tasks don't alone describe the primary motivation for using Twitter. People use Twitter to keep up with and share what's happening, and that news often comes in the form of a web link. Browsing the web is an essential secondary task for browsing a Twitter stream, and launching Safari for every link would simply make a Twitter app feel broken. Similarly, the main job for apps that help you find nearby restaurants or drinking holes is to show you their names, addresses, and perhaps some brief descriptions or reviews. But the inevitable follow-on task is to see the best candidates on a map, or to email the info to friends you plan to meet there. In all of these scenarios, the secondary tasks are important and frequent enough that you shouldn't link to other apps for them. Instead, trigger a new screen or modal view within your app to handle browsing, mapping, or mailing.