Android Auto - Map Rendering Development

# Android Automotive OS Map Rendering Implementation

## Project Overview
We need to implement a map rendering solution for an Android Automotive OS application. The application currently displays route information in item rows but requires proper map visualization in the background using the Android Automotive OS

## Current Implementation
We have a working `RouteMapScreen` class that handles:
- Route data fetching and display
- List of routes with distance, duration, and cost
- Basic UI templates using Android Automotive OS components
- MapWithContentTemplate integration

## Technical Requirements

### Core Functionality Needed
1. **Map Background Rendering**
- Implement map rendering
- Display map background with proper scaling and positioning
- Smooth rendering performance

2. **Route Visualization**
- Draw route paths on the map
- Display start/end markers & fuel station markers enroute
- Highlight selected route
- Support for multiple route options

3. **Interactive Features**
- Pan and zoom functionality
- Map recentering
- Route selection visualization
- Smooth transitions between states

### Technical Specifications
- Language: Kotlin
- Platform: Android Automotive OS
- Key APIs:
- Android Automotive OS Surface API
- MapController
- SurfaceCallback
- Canvas drawing
- Matrix transformations

### Current Code

import androidx.car.app.CarContext
import androidx.car.app.Screen
import androidx.car.app.model.*
import androidx.car.app.navigation.model.MapController
import androidx.car.app.navigation.model.MapWithContentTemplate
import kotlinx.coroutines.*
import android.util.Log
import androidx.core.graphics.drawable.IconCompat

class RouteMapScreen(
carContext: CarContext,
private val searchText: String
) : Screen(carContext) {

private val dataManager = DataManager(carContext)
private val coroutineScope = CoroutineScope(Dispatchers.Main + Job())
private var routeData: FuelEfficientRouteResponse? = null
private lateinit var mapController: MapController

override fun onGetTemplate(): Template {
// Start fetching route data asynchronously
coroutineScope.launch {
routeData = dataManager.fetchRouteData(searchText)
invalidate() // Triggers a new call to onGetTemplate() after data fetch completes
}

// Show a loading screen while data is being fetched
if (routeData == null) {
return MessageTemplate.Builder("Loading routes...")
.build()
}

// If route data was fetched successfully, create the map with content template
return if (routeData!!.routes.isNotEmpty()) {
val itemListBuilder = ItemList.Builder()
routeData!!.routes.forEachIndexed { index, route ->
val row = Row.Builder()
.setTitle("Route ${index + 1}: ${route.distance} - ${route.duration}")
.addText("Cost: ${route.trip_cost.trip_summary}")
.setOnClickListener { onRouteSelected(index) }
.build()
itemListBuilder.addItem(row)
}

val listTemplate = ListTemplate.Builder()
.setSingleList(itemListBuilder.build())
.build()

val mapActionStrip = ActionStrip.Builder()
.addAction(Action.Builder()
.setIcon(CarIcon.APP_ICON) // Replace with appropriate icon
.setOnClickListener { /* Handle map action */ }
.build())
.build()

val mapController = MapController.Builder()
.setMapActionStrip(mapActionStrip)
.build()

MapWithContentTemplate.Builder()
.setMapController(mapController)
.setContentTemplate(listTemplate)
.build()
} else {
// If no routes are found, show a message
MessageTemplate.Builder("No routes found.")
.setHeaderAction(Action.BACK)
.build()
}
}

private fun getMapController(): MapController {
val panAction = Action.Builder()
.setIcon(CarIcon.APP_ICON) // Replace with appropriate icon
.setOnClickListener { /* Handle pan action */ }
.build()

val zoomInAction = Action.Builder()
.setIcon(CarIcon.APP_ICON) // Replace with appropriate icon
.setOnClickListener { /* Handle zoom in action */ }
.build()

val zoomOutAction = Action.Builder()
.setIcon(CarIcon.APP_ICON) // Replace with appropriate icon
.setOnClickListener { /* Handle zoom out action */ }
.build()

val mapActionStrip = ActionStrip.Builder()
.addAction(panAction)
.addAction(zoomInAction)
.addAction(zoomOutAction)
.build()

return MapController.Builder()
.setMapActionStrip(mapActionStrip)
.build()
}

private fun onNavigate() {
// Handle navigation action
Log.i("RouteMapScreen", "Navigate action clicked")
// Implement navigation logic here
}

private fun onRouteSelected(index: Int) {
// Handle route selection
Log.i("RouteMapScreen", "Selected Route: $index")
// Implement route selection logic here, e.g., start navigation
}

fun cleanup() {
// Cleanup coroutine scope if needed
coroutineScope.cancel() // Cancels any ongoing coroutines to avoid memory leaks
}
}