carcontext

Android Auto is a popular platform that allows users to seamlessly integrate their Android devices with their car’s infotainment system. This integration extends to navigation, allowing users to launch navigation apps like Google Maps or Waze directly from Android Auto. In this blog post, we’ll explore how to achieve this functionality from within your Android application using .NET MAUI.

The key to launching navigation apps on Android Auto is to construct a URI with the desired latitude and longitude and use an Intent to open the navigation app. Let’s break down the code snippet you provided to understand how it works:

public class NavigationOnClickListener : Java.Lang.Object, IOnClickListener
{
    private readonly CarContext _context;
    private readonly double _latitude;
    private readonly double _longitude;

    public NavigationOnClickListener(CarContext context, double latitude, double longitude)
    {
        _context = context;
        _latitude = latitude;
        _longitude = longitude;
    }

    public void OnClick()
    {
        string uri = $"geo:{_latitude.ToString(CultureInfo.InvariantCulture)},{_longitude.ToString(CultureInfo.InvariantCulture)}";
        Intent intent = new Intent(CarContext.ActionNavigate)
            .SetData(AndroidUri.Parse(uri));
        _context.StartCarApp(intent);
    }
}

AndroidUri is the Android.Net.Uri class alias achieved by:

using AndroidUri = Android.Net.Uri;

Let’s dissect this code step by step:

1. NavigationOnClickListener is a custom class that implements the IOnClickListener interface. This class is responsible for handling the click event that launches the navigation app.
2. In the constructor, we receive three parameters: context, latitude, and longitude. context is the CarContext instance, and latitude and longitude are the destination coordinates (double).
3. Inside the OnClick method, we construct a URI in the following format: "geo:latitude,longitude". The CultureInfo.InvariantCulture is used to ensure that the decimal separator is a period (.) rather than a comma (,) to make the URI universally compatible. This is crucial because different regions may use different formats for numbers.
4. We create an Intent with the action CarContext.ActionNavigate. This action specifies that we want to launch a navigation app.
5. We set the data of the intent by parsing the constructed URI using AndroidUri.Parse(uri).
6. Finally, we start the navigation app by invoking _context.StartCarApp(intent).