Bridging options for notifications

By default, notifications are bridged (shared) from an app on a phone to any paired watches. If you build a watch app and your app also exists on a paired phone, users may receive duplicate notifications—one generated by the phone app (bridged), and one generated by the watch app. Wear OS includes features to control how and when notifications are "bridged".

Avoid duplicate notifications

When you create notifications from an external source, such as from Firebase Cloud Messaging, your mobile app and your wearable app may each display its own notifications on the watch. To avoid this sort of duplication, your wearable app should programmatically disable bridging.

1. In the mobile app, use bridge tags when applicable

If you want to bridge some of the notifications created on your mobile app to the watch when your wearable app is installed, set bridge tags.

Set a bridge tag

Set a bridge tag on a notification by using the setBridgeTag(String) method as shown in the following code sample: 

val notification = NotificationCompat.Builder(context, channelId)
    // ... set other fields ...
    .extend(
        NotificationCompat.WearableExtender()
            .setBridgeTag("foo")
    )
    .build()

2. In the wearable app, disable bridging

Disable bridging for some notifications

You can dynamically disable bridging, and optionally allow some notifications through depending on their tag. For example, to disable bridging for all notifications except those tagged as foo, bar, or baz, use the BridgingConfig object as shown in this section. 

BridgingManager.fromContext(context).setConfig(
    BridgingConfig.Builder(context, false)
        .addExcludedTags(listOf("foo", "bar", "baz"))
        .build()
)

Disable bridging for all notifications (not recommended)

Note: Disabling bridging for all notifications is not recommended because the bridging configuration set in the manifest takes effect as soon as a watch app is installed. This can lead to notifications being lost if the user needs to open and setup the watch app before receiving notifications.

To prevent bridging of all notifications from a phone app, use the <meta-data> entry in the manifest file of the watch app, as shown in the following example: 

<application>
...
  <!-- Beware this can have unintended consqequences before the user is signed-in -->
  <meta-data
    android:name="com.google.android.wearable.notificationBridgeMode"
    android:value="NO_BRIDGING" />
...
</application>

Note: Specifying a bridging configuration at runtime overrides a bridging-related setting in the Android manifest file.

3. Set a dismissal ID to sync similar notifications on Wear OS and mobile

When you prevent bridging with the bridging mode feature, dismissals of notifications are not synced across a user's devices.

However, if similar notifications are created on both mobile and the watch, you still want both notifications dismissed if the user dismisses any one of them.

In the NotificationCompat.WearableExtender, you can set a global unique id, so that when one notification is dismissed, other notifications with the same ID on paired watch(es) will also be dismissed.

The NotificationCompat.WearableExtender class has methods that enable you to use dismissal IDs, as shown in the following example: 

fun setDismissalId(dismissalId: String): WearableExtender
fun getDismissalId(): String

To sync a dismissal, use the setDismissalId() method. For each notification, pass a globally unique ID, as a string, when you call the setDismissalId() method.

When the notification is dismissed, all other notifications with the same dismissal ID are dismissed on the watch(es) and on the phone. To retrieve a dismissal ID, use getDismissalId().

In the following example, syncing of dismissals is enabled because a globally unique ID is specified for a new notification: 

val notification = NotificationCompat.Builder(context, channelId)
    // ... set other fields ...
    .extend(
        NotificationCompat.WearableExtender()
            .setDismissalId("abc123")
    )
    .build()

Note: Dismissal IDs work if a watch is paired to an Android phone, but not if a watch is paired to an iPhone.

When notifications aren't bridged

Notifications are not bridged in the following cases:

Best practices for bridged notifications

It takes time to push or remove bridged notifications from a wearable device. As you design your notifications, make sure to avoid unexpected behavior caused by this latency. The following guidelines ensure that your bridged notifications work with asynchronous notifications:

  • If you cancel a notification on the phone, it may take some time to cancel the corresponding notification on the watch. During this time, a user could send one of the pending intents on that notification. For this reason, your app should receive pending intents from notifications it has canceled. Thus, when canceling notifications, make sure to keep those notifications’ pending intent receivers valid.
  • Don't cancel and retrigger an entire stack of notifications at one time. Only modify or remove the notifications that have actually been modified. This avoids the latency on updating the wearable device and ensures that the impact of your app on battery life is minimal.

Design considerations

Wear OS notifications have their own design guidelines. For more information, review the Wear OS Design Guidelines.