I don't know how to display notifications on the DHU side with messaging apps.

I would like to implement ["Incoming messages"](https://developers.google.com/cars/design/android-auto/apps/incoming-messages?hl=ja) and ["Saved messages"](https://developers.google.com/cars/design/android-auto/apps/saved-messages?hl=ja). Is there a github project that explains the detailed implementation?

I tested the execution of the app based on the "Messaging Service Template" of Android Studio, but nothing was notified to the DHU side.

This repository will be helpful when creating apps using the [Cars App Library](https://developer.android.com/training/cars/Android%20for%20Cars%20App%20Library%20design%20guidelines.pdf).
When creating media apps, the [uamp](https://github.com/android/uamp) repository will be helpful.
However, there is no sample project on github to help me create messaging apps.

my project: https://github.com/LeoAndo/android-auto-automotive-training/tree/main/MessageSimpleApp
| Mobile(Google Pixel5 OS12) | DHU v2 |
|:---|:---:|
| | |

## about Android Studio Template

In my opinion, the code in ["Android Studio Messaging Service Templates"](https://user-images.githubusercontent.com/16476224/172122715-c81acf7e-fc26-44ff-949d-aac122058340.png) is old, can't be run right away, and isn't very helpful.(There is no implementation of [NotificationChannel](https://developer.android.com/reference/android/app/NotificationChannel) etc.)
Issues that cannot be run immediately have been [submitted to the issue Tracker](https://issuetracker.google.com/issues/229007489).

The issue points to MessageSimpleApp, the Android Studio Messaging Service Template, Cars App Library guidance, and the DHU setup. Start by reproducing the reported behavior with that project and compare it with the linked Incoming messages and Saved messages documentation. Done would be a repository sample or documentation that demonstrates those notifications working on the DHU.

Written by the indexing model from the issue text.