Speed limit
The Mapbox Navigation SDK allows you to present speed limit information in your application using a pre-built UI component.
Use the default speed limit UI component
The default speed limit UI component, MapboxSpeedLimitView, displays the speed limit of the road the user is traveling on.
Render the speed limit of the current road using the Speed Limit API and MapboxSpeedLimitView.
Add the view to the layout
Start by adding the MapboxSpeedLimitView to your activity or fragment layout. The sample code below positions the speed limit UI component on top of a map.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.mapbox.maps.MapView
android:id="@+id/mapView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
/>
<com.mapbox.navigation.ui.speedlimit.view.MapboxSpeedLimitView
android:id="@+id/speedLimitView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="@dimen/mapbox_dimen_8dp"
android:layout_marginBottom="@dimen/mapbox_dimen_8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Create an instance of the Speed Limit API
The Speed Limit API formats speed limit data to be used in the speed limit UI component..
Create an instance of MapboxSpeedLimitApi.
// Define speed limit formatter options
private val speedLimitFormatter: SpeedLimitFormatter by lazy {
SpeedLimitFormatter(this)
}
// Create an instance of the Speed Limit API
private val speedLimitApi: MapboxSpeedLimitApi by lazy {
MapboxSpeedLimitApi(speedLimitFormatter)
}
Start receiving map matching events
The updates for the speed limit component are powered by the LocationObserver. Create an observer in your activity or fragment and register it with MapboxNavigation. Be sure to unregister the LocationObserver in either onStop or onDestroy to avoid leaking resources.
private val locationObserver = object : LocationObserver {
override fun onNewRawLocation(rawLocation: Location) {
...
}
override fun onNewLocationMatcherResult(locationMatcherResult: LocationMatcherResult) {
val value = speedLimitApi.updateSpeedLimit(locationMatcherResult.speedLimit)
binding.speedLimitView.render(value)
}
}
MapboxSpeedLimitApi will be Expected, and the displayed value will be "--". If it better suites your use case, you may decide to hide and show the speed limit component based on the value returned by the MapboxSpeedLimitApi.