In addition to the basic notification-powered messaging experience for reading and replying to messages, Android Auto supports richer messaging experiences built using the Android for Cars App Library.
Support notification-powered messaging experiences
All apps that support templated messaging experiences must also extend messaging notifications for Android Auto. This ensures that users are able to read and reply to messages without having to open the templated app.
Build a templated messaging experience
Follow the guidance in Use the Android for Cars App Library and Add support for Android Auto to your templated app to get started building your app's templated experience. Then, refer to the guidance on this page to understand the specific requirements for templated messaging apps.
Configure your app's manifest files
To inform Android Auto of your app's capabilities, your app must do the following:
Declare category support in your manifest
Your app needs to declare the androidx.car.app.category.MESSAGING car app
category in the intent filter of its
CarAppService.
<application>
...
<service
...
android:name=".MyCarAppService"
android:exported="true">
<intent-filter>
<action android:name="androidx.car.app.CarAppService" />
<category android:name="androidx.car.app.category.MESSAGING"/>
</intent-filter>
</service>
...
<application>
Set the minimum car app API level
Because the ConversationItem API is only supported on Car
API 7 or higher, you should also set the minCarApiLevel metadata to that
value. See Car App API Level for more information.
<application ...>
...
<meta-data
android:name="androidx.car.app.minCarApiLevel"
android:value="7"/>
...
</application>
Declare Android Auto support
In the automotive_app_desc.xml file that you use to declare Android Auto
support, ensure that both the notification and
template capabilities are declared:
<automotiveApp>
<uses name="notification" />
<uses name="template" />
</automotiveApp>
If your app can be set as the default SMS handler,
make sure to include the following <uses> element. If you don't, a default
handler built-in to Android Auto will be used to handle incoming SMS/MMS
messages, which can lead to duplicate notifications.
<automotiveApp>
...
<uses name="sms" />
</automotiveApp>
Display conversations
To display an overview of a user's conversations, you can display a list of
ConversationItem objects in a
ListTemplate or
SectionedItemTemplate.
For the best user experience, we recommend providing at most the 5-10 most recent or most important conversations, with no more than the 5 most recent messages for each conversation. This helps improve loading performance, ensures users see the most relevant content, and reduces interaction time.
class MyMessagingScreen() : Screen() {
override fun onGetTemplate(): Template {
val itemListBuilder = ItemList.Builder()
val conversations: List<MyConversation> = // Retrieve conversations
for (conversation: MyConversation in conversations) {
val carMessages: List<CarMessage> = conversation.getMessages()
.map { message ->
// CarMessage supports additional fields such as MIME type and URI,
// which you should set if available
CarMessage.Builder()
.setSender(message.sender)
.setBody(message.body)
.setReceivedTimeEpochMillis(message.receivedTimeEpochMillis)
.setRead(message.isRead)
.build()
}
itemListBuilder.addItem(
ConversationItem.Builder()
.setConversationCallback { /* Implement your conversation callback logic here */ }
.setId(/* Set conversation ID */)
.setTitle(/* Set conversation title */)
.setIcon(/* Set conversation icon if available */)
.setMessages(carMessages)
/* When the sender of a CarMessage is equal to this Person,
message readout is adjusted to "you said" instead of "<person>
said" */
.setSelf(/* Set self-sender */)
.setGroupConversation(/* Set if the message contains more than 2 participants */)
.build()
)
}
return ListTemplate.Builder()
.setTitle("Conversations")
.setHeaderAction(Action.APP_ICON)
.setSingleList(itemListBuilder.build())
.build()
}
}
Each ConversationItem automatically displays actions for playing a message
and marking it as read as and for replying. Those actions are handled by the
ConversationCallbackDelegate you supply when
building the ConversationItem.
If your app provides conversation shortcuts, ensure
that the ID provided when building the ConversationItem is the same as the
ID for that conversation's shortcut.
Update conversations
As users send and receive messages, you should refresh your app's screens to
include the new messages by calling invalidate(). See Refresh
the contents of a template.
For the best user experience, we recommend keeping refresh times to 500 milliseconds or fewer. If refreshing frequently takes longer, you can display a loading state while you load the incoming messages.
Set notification importance appropriately
To reduce distractions, your app should lower the importance of incoming notifications when a user is using your viewing a corresponding conversation so the notifications don't appear as heads up notifications (HUNs).
You can track if a conversation is visible by observing the lifecycle of the
Screen that displays it. See The lifecycle of a screen.
To prevent a notification from appearing as a HUN, set the priority to
IMPORTANCE_DEFAULT or lower.
Distribute templated messaging apps
Because apps that support templated messaging experiences can only be published to Internal Testing and Closed Testing tracks on Google Play, you shouldn't promote builds that include support to Open Testing or Production tracks, as submissions containing builds on those tracks will be rejected.