Posted by Joshua Gordon, Developer Advocate
What if there was a way for drivers to stay connected using your messaging app, while keeping their hands on the wheel and eyes on the road?
Android Auto helps drivers stay connected, but in a more convenient way that's integrated with the car. It eliminates the need to type and read messages by replacing these activities with a voice controlled interface.
Enabling your messaging app to work with Android Auto is easy. Developers like Skype and textPlus have already done so. Check out this DevByte for an overview of the messaging APIs, and see the developer training guide for a deep dive. Read on for a look at the key steps involved.
Message notifications on the car’s display
When an Android 5.0+ phone is connected to a compatible car, users receive incoming message notifications from Auto-enabled apps on the car’s head unit display. Your app runs on the phone, but is controlled by the car. To learn more about how this works, watch the Introduction to Android Auto DevByte.
A new message notification from Skype
If your app already uses notifications to alert the user to incoming messages, it’ll be easy to extend these for Auto. It takes just a few lines of code, and you won’t have to change how your app works on the phone.
There are a couple small differences between message notifications on Auto vs. a phone. On Auto, a preview of the message content isn’t shown, because messaging is driven entirely by voice. Second, message notifications are backed by a conversation object. This is simply a collection of unread messages from a particular sender.
Decorate your notification with the CarExtender to add support for the car. Next, use the UnreadConversation.Builder to create a conversation, and populate it by iterating over your app's unread messages (from a certain sender) and adding them to the conversation. Pass your conversation object to the CarExtender, and you’re done!
Tap to hear messages
Tapping on a message notification plays it back on the car's sound system, via text to speech. This is handled automatically by the framework; no additional code is required. Pretty cool, right?
In order to know when the user hears a message, you provide a PendingIntent that’s triggered by the system. That’s one of just two intents you’ll need to handle to enable your app for Auto.
Reply by voice
Voice control is the real magic of Android Auto. Users reply to messages by speaking, via voice recognition. This is far faster and more natural than typing.
Enabling this functionality is as simple as adding a RemoteInput instance to your conversation objects, before you issue the notification. Speech recognition is handled entirely by the framework. The recognition result is delivered to your app as a plain text string via a second PendingIntent.
Replying to a message from textPlus by voice.
Next Steps
Make your messaging app more natural to use in the car by enabling it for Android Auto. Now drivers can stay connected, without typing or reading messages. It just takes a few lines of code. To learn more visit developer.android.com/auto
