feat(navigation): Implement place search along route and example

navigation-app/src/main/java/com/google/maps/android/compose/navigation/MainActivity.kt

@@ -53,6 +53,8 @@ class MainActivity : ComponentActivity() {
             )
 
             val location by myViewModel.location.collectAsStateWithLifecycle()
+            val placesAlongRoute by myViewModel.placesAlongRoute.collectAsStateWithLifecycle()
+            val routeReady by myViewModel.routeReady.collectAsStateWithLifecycle()
 
             fun onShowSnackbar(message: String) {
                 scope.launch {
@@ -80,11 +82,18 @@ class MainActivity : ComponentActivity() {
                 Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
                     NavigationScreen(
                         modifier = Modifier.padding(innerPadding),
-                        deviceLocation = location
+                        deviceLocation = location,
+                        placesAlongRoute = placesAlongRoute,
+                        routeReady = routeReady,
+                        onClearSearchResults = {
+                            myViewModel.clearSearchResults()
+                        },
+                        onSearchClicked = {
+                            myViewModel.searchAlongRoute(it)
+                        }
                     )
                 }
             }
         }
     }
 }
-

navigation-app/src/main/java/com/google/maps/android/compose/navigation/NavigationScreen.kt

@@ -2,12 +2,25 @@ package com.google.maps.android.compose.navigation
 
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Button
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.OutlinedCard
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.ui.Alignment
@@ -20,6 +33,7 @@ import com.google.android.gms.maps.CameraUpdateFactory
 import com.google.android.gms.maps.model.CameraPosition
 import com.google.android.gms.maps.model.LatLng
 import com.google.android.libraries.navigation.NavigationView
+import com.google.android.libraries.places.api.model.Place
 import com.google.maps.android.compose.ComposeMapColorScheme
 import com.google.maps.android.compose.GoogleMap
 import com.google.maps.android.compose.MarkerComposable
@@ -30,7 +44,11 @@ import com.google.maps.android.compose.rememberMarkerState
 @Composable
 fun NavigationScreen(
     deviceLocation: LatLng?,
-    modifier: Modifier = Modifier
+    placesAlongRoute: List<Place>,
+    onClearSearchResults: () -> Unit,
+    onSearchClicked: (String) -> Unit,
+    routeReady: Boolean,
+    modifier: Modifier = Modifier,
 ) {
     val cameraPositionState = rememberCameraPositionState {
         position = CameraPosition.fromLatLngZoom(
@@ -53,6 +71,59 @@ fun NavigationScreen(
     Column(
         modifier = modifier
     ) {
+        if (placesAlongRoute.isNotEmpty()) {
+            OutlinedCard(
+                modifier = Modifier.height(250.dp).fillMaxWidth()
+            ) {
+                Box(
+                    modifier = Modifier.padding(16.dp),
+                ) {
+                    LazyColumn(
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .padding(16.dp),
+                        verticalArrangement = Arrangement.spacedBy(8.dp)
+                    ) {
+                        items(placesAlongRoute) { place ->
+                            PlaceItem(place)
+                        }
+                    }
+
+                    IconButton(
+                        onClick = onClearSearchResults,
+                        modifier = Modifier
+                            .align(Alignment.TopEnd)
+                            .padding(8.dp)
+                    ) {
+                        Icon(Icons.Filled.Close, contentDescription = "Close")
+                    }
+                }
+            }
+        } else if (routeReady) {
+            OutlinedCard(
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                Row(modifier = Modifier.fillMaxWidth()) {
+                    Button(
+                        modifier = Modifier.weight(1f),
+                        onClick = {
+                            onSearchClicked("Spicy Vegetarian Food")
+                        }
+                    ) {
+                        Text("Spicy Veg")
+                    }
+                    Button(
+                        modifier = Modifier.weight(1f),
+                        onClick = {
+                            onSearchClicked("Pizza")
+                        }
+                    ) {
+                        Text("Pizza")
+                    }
+                }
+            }
+        }
+
         GoogleMap(
             modifier = Modifier.fillMaxSize(),
             cameraPositionState = cameraPositionState,
@@ -89,3 +160,9 @@ fun NavigationScreen(
         }
     }
 }
+
+@Composable
+fun PlaceItem(place: Place) {
+    // Should probably filter these.  I would not use the place object directly.
+    Text(place.displayName ?: "Unknown place")
+}

navigation-app/src/main/java/com/google/maps/android/compose/navigation/NavigationViewModel.kt

@@ -31,10 +31,14 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import com.google.android.gms.tasks.CancellationTokenSource
 import com.google.android.libraries.navigation.ListenableResultFuture
+import com.google.android.libraries.places.api.model.EncodedPolyline
+import com.google.android.libraries.places.api.model.Place
+import com.google.android.libraries.places.api.model.SearchAlongRouteParameters
+import com.google.android.libraries.places.api.net.kotlin.awaitSearchByText
+import com.google.maps.android.ktx.utils.latLngListEncode
 import kotlin.coroutines.resume
 import kotlin.coroutines.resumeWithException
 import kotlin.coroutines.suspendCoroutine
-import com.google.maps.android.compose.navigation.BuildConfig
 
 class NavigationViewModel(
     private val placesClient: PlacesClient,
@@ -60,6 +64,12 @@ class NavigationViewModel(
 
     private var navigator: Navigator? = null
 
+    private val _placesAlongRoute = MutableStateFlow<List<Place>>(emptyList())
+    val placesAlongRoute = _placesAlongRoute.asStateFlow()
+
+    private val _routeReady = MutableStateFlow(false)
+    val routeReady = _routeReady.asStateFlow()
+
     init {
         viewModelScope.launch {
             _hasLocationPermission.collect() {
@@ -204,9 +214,43 @@ class NavigationViewModel(
             travelMode(RoutingOptions.TravelMode.DRIVING)
         }
 
+        // Listen for route changes
+        navigator.addRouteChangedListener {
+            Log.d("NavigationContainer", "Route changed")
+            _routeReady.value = true
+            //            viewModelScope.launch {
+            //                val placeFields = listOf(Place.Field.ID, Place.Field.DISPLAY_NAME)
+            //                searchAlongRoute("Spicy Vegetarian Food", placeFields)
+            //            }
+        }
+
         navigateToPlace(chautauquaDinningHall, routingOptions)
     }
 
+    private suspend fun searchAlongRoute(searchText: String, placeFields: List<Place.Field>) {
+        val route = navigator?.currentRouteSegment?.latLngs
+
+        if (route.isNullOrEmpty()) {
+            Log.d("NavigationContainer", "No route found")
+            return
+        }
+
+        val encodedPolyline = EncodedPolyline.newInstance(route.latLngListEncode())
+
+        val searchAlongRouteParameters = SearchAlongRouteParameters.newInstance(encodedPolyline)
+
+        val response = placesClient.awaitSearchByText(searchText, placeFields) {
+            setSearchAlongRouteParameters(searchAlongRouteParameters)
+            maxResultCount = 10
+        }
+
+        response.places.forEach {
+            Log.d("Gollum", "Place ID: ${it.id}, Display Name: ${it.displayName}")
+        }
+
+        _placesAlongRoute.value = response.places
+    }
+
     override fun onError(@NavigationApi.ErrorCode errorCode: Int) {
         when (errorCode) {
             NavigationApi.ErrorCode.NOT_AUTHORIZED -> displayMessage(
@@ -235,5 +279,14 @@ class NavigationViewModel(
             _uiEvent.emit(UiEvent.ShowSnackbar(message))
         }
     }
-}
 
+    fun clearSearchResults() {
+        _placesAlongRoute.value = emptyList()
+    }
+
+    fun searchAlongRoute(searchText: String) {
+        viewModelScope.launch {
+            searchAlongRoute(searchText, listOf(Place.Field.ID, Place.Field.DISPLAY_NAME))
+        }
+    }
+}

navigation-app/src/main/java/com/google/maps/android/compose/navigation/SearchAlongRouteExample.kt

@@ -0,0 +1,81 @@
+package com.google.maps.android.compose.navigation
+
+import android.util.Log
+import com.google.android.gms.maps.model.LatLng
+import com.google.android.libraries.navigation.NavigationApi
+import com.google.android.libraries.navigation.NavigationApi.NavigatorListener
+import com.google.android.libraries.navigation.Navigator
+import com.google.android.libraries.places.api.model.EncodedPolyline
+import com.google.android.libraries.places.api.model.Place
+import com.google.android.libraries.places.api.model.SearchAlongRouteParameters
+import com.google.android.libraries.places.api.net.PlacesClient
+import com.google.maps.android.ktx.utils.latLngListEncode
+import com.google.android.libraries.places.api.net.kotlin.awaitSearchByText
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+
+/**
+ * Holds an instance of the navigator class.  Most likely an activity or a view model.  Take a look at NavigationViewModel
+ */
+class NavigationContainer(
+    private val placesClient: PlacesClient,
+    private val scope: CoroutineScope,
+) : NavigatorListener {
+    private var navigator: Navigator? = null
+
+    override fun onError(@NavigationApi.ErrorCode errorCode: Int) {
+        when (errorCode) {
+            NavigationApi.ErrorCode.NOT_AUTHORIZED -> displayMessage(
+                "Error loading Navigation SDK: Your API key is "
+                        + "invalid or not authorized to use the Navigation SDK."
+            )
+
+            NavigationApi.ErrorCode.TERMS_NOT_ACCEPTED -> displayMessage(
+                "Error loading Navigation SDK: User did not accept "
+                        + "the Navigation Terms of Use."
+            )
+
+            NavigationApi.ErrorCode.NETWORK_ERROR -> displayMessage("Error loading Navigation SDK: Network error.")
+            NavigationApi.ErrorCode.LOCATION_PERMISSION_MISSING -> displayMessage(
+                "Error loading Navigation SDK: Location permission "
+                        + "is missing."
+            )
+
+            else -> displayMessage("Error loading Navigation SDK: $errorCode")
+        }
+    }
+
+    private fun displayMessage(message: String) {
+        // Could show a snackbar or toast here
+        Log.w("NavigationContainer", message)
+    }
+
+    override fun onNavigatorReady(navigator: Navigator?) {
+        this.navigator = navigator ?: error("Navigator is null")
+        navigator.addRouteChangedListener {
+            Log.d("NavigationContainer", "Route changed")
+            scope.launch {
+                navigator.currentRouteSegment?.latLngs?.let { route ->
+                    //pass the encoded string to a function to perform the search
+                    searchPlacesAlongRoute(route)
+                }
+            }
+        }
+    }
+
+    private suspend fun searchPlacesAlongRoute(route: List<LatLng>) {
+        val encodedPolyline = EncodedPolyline.newInstance(route.latLngListEncode())
+        val placeFields = listOf(Place.Field.ID, Place.Field.DISPLAY_NAME)
+
+        val searchAlongRouteParameters = SearchAlongRouteParameters.newInstance(encodedPolyline)
+
+        val response = placesClient.awaitSearchByText("Spicy Vegetarian Food", placeFields) {
+            setSearchAlongRouteParameters(searchAlongRouteParameters)
+            maxResultCount = 10
+        }
+
+        response.places.forEach {
+            Log.d("Places API", "Place ID: ${it.id}, Display Name: ${it.displayName}")
+        }
+    }
+}