feat: Use AndroidView overload which re-uses MapView to improve performance in lazy layouts

app/src/main/AndroidManifest.xml

@@ -48,6 +48,9 @@
     <activity
         android:name=".MapInColumnActivity"
         android:exported="false"/>
+    <activity
+        android:name=".MapsInLazyColumnActivity"
+        android:exported="false"/>
     <activity
         android:name=".markerexamples.MarkerClusteringActivity"
         android:exported="false"/>

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

@@ -102,6 +102,18 @@ class MainActivity : ComponentActivity() {
                             Text(getString(R.string.map_in_column_activity))
                         }
                         Spacer(modifier = Modifier.padding(5.dp))
+                        Button(
+                            onClick = {
+                                context.startActivity(
+                                    Intent(
+                                        context,
+                                        MapsInLazyColumnActivity::class.java
+                                    )
+                                )
+                            }) {
+                            Text(getString(R.string.maps_in_lazy_column_activity))
+                        }
+                        Spacer(modifier = Modifier.padding(5.dp))
                         Button(
                             onClick = {
                                 context.startActivity(

app/src/main/java/com/google/maps/android/compose/MapsInLazyColumnActivity.kt

@@ -0,0 +1,260 @@
+package com.google.maps.android.compose
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.horizontalScroll
+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.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.material.Card
+import androidx.compose.material.CircularProgressIndicator
+import androidx.compose.material.LocalTextStyle
+import androidx.compose.material.ProvideTextStyle
+import androidx.compose.material.Text
+import androidx.compose.material.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.google.android.gms.maps.GoogleMap
+import com.google.android.gms.maps.model.CameraPosition
+import com.google.android.gms.maps.model.IndoorBuilding
+import com.google.android.gms.maps.model.LatLng
+
+private data class CountryLocation(val name: String, val latLng: LatLng, val zoom: Float)
+
+private typealias MapItemId = String
+
+// From https://developers.google.com/public-data/docs/canonical/countries_csv
+private val countries = listOf(
+    CountryLocation("Hong Kong", LatLng(22.396428, 114.109497), 5f),
+    CountryLocation("Madison Square Garden (has indoor mode)", LatLng(40.7504656, -73.9937246), 19.33f),
+    CountryLocation("Bolivia", LatLng(-16.290154, -63.588653), 5f),
+    CountryLocation("Ecuador", LatLng(-1.831239, -78.183406), 5f),
+    CountryLocation("Sweden", LatLng(60.128161, 18.643501), 5f),
+    CountryLocation("Eritrea", LatLng(15.179384, 39.782334), 5f),
+    CountryLocation("Portugal", LatLng(39.399872, -8.224454), 5f),
+    CountryLocation("Belgium", LatLng(50.503887, 4.469936), 5f),
+    CountryLocation("Slovakia", LatLng(48.669026, 19.699024), 5f),
+    CountryLocation("El Salvador", LatLng(13.794185, -88.89653), 5f),
+    CountryLocation("Bhutan", LatLng(27.514162, 90.433601), 5f),
+    CountryLocation("Saint Lucia", LatLng(13.909444, -60.978893), 5f),
+    CountryLocation("Uganda", LatLng(1.373333, 32.290275), 5f),
+    CountryLocation("South Africa", LatLng(-30.559482, 22.937506), 5f),
+    CountryLocation("Spain", LatLng(40.463667, -3.74922), 5f),
+    CountryLocation("Georgia", LatLng(42.315407, 43.356892), 5f),
+    CountryLocation("Burundi", LatLng(-3.373056, 29.918886), 5f)
+)
+
+private data class MapListItem(
+    val title: String,
+    val location: LatLng,
+    val zoom: Float,
+    val id: MapItemId
+)
+
+private val allItems = countries.mapIndexed { index, country ->
+    MapListItem(country.name, country.latLng, country.zoom, "MapInLazyColumn#$index")
+}
+
+class MapsInLazyColumnActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        setContent {
+            var showLazyColumn by rememberSaveable { mutableStateOf(true) }
+            var visibleItems by rememberSaveable { mutableStateOf(allItems) }
+
+            fun setItemCount(count: Int) {
+                visibleItems = allItems.take(count.coerceIn(0, allItems.size))
+            }
+
+            Column {
+                Row(
+                    Modifier
+                        .fillMaxWidth()
+                        .horizontalScroll(rememberScrollState()),
+                    horizontalArrangement = Arrangement.SpaceEvenly
+                ) {
+                    TextButton(onClick = { setItemCount(0) }) {
+                        Text(text = "Clear")
+                    }
+                    TextButton(onClick = { setItemCount(visibleItems.size - 1) }) {
+                        Text(text = "Remove")
+                    }
+                    TextButton(onClick = { showLazyColumn = !showLazyColumn }) {
+                        Text(text = if (showLazyColumn) "Hide" else "Show")
+                    }
+                    TextButton(onClick = { setItemCount(visibleItems.size + 1) }) {
+                        Text(text = "Add")
+                    }
+                    TextButton(onClick = { setItemCount(allItems.size) }) {
+                        Text(text = "Fill")
+                    }
+                }
+                if (showLazyColumn) {
+                    Box(Modifier.border(1.dp, Color.LightGray.copy(0.5f))) {
+                        MapsInLazyColumn(visibleItems)
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun MapsInLazyColumn(mapItems: List<MapListItem>) {
+    val lazyListState = rememberLazyListState()
+
+    val cameraPositionStates = mapItems.associate { item ->
+        item.id to rememberCameraPositionState(
+            key = item.id,
+            init = { position = CameraPosition.fromLatLngZoom(item.location, item.zoom) }
+        )
+    }
+    val visibleItemIds by remember(lazyListState) {
+        derivedStateOf {
+            lazyListState.layoutInfo.visibleItemsInfo.map { it.key as MapItemId }
+        }
+    }
+    val anyMapMoving by remember(cameraPositionStates) {
+        derivedStateOf {
+            visibleItemIds.any { cameraPositionStates[it]?.isMoving == true }
+        }
+    }
+
+    Box {
+        LazyColumn(
+            state = lazyListState,
+            userScrollEnabled = !anyMapMoving
+        ) {
+            items(mapItems, key = { it.id }) { item ->
+                val cameraPositionState = cameraPositionStates[item.id]!!
+
+                Box(
+                    Modifier
+                        .fillMaxWidth()
+                        .height(300.dp),
+                    contentAlignment = Alignment.Center
+                ) {
+                    MapCard(item, cameraPositionState)
+                }
+            }
+        }
+    }
+}
+
+@OptIn(MapsComposeExperimentalApi::class)
+@Composable
+private fun MapCard(item: MapListItem, cameraPositionState: CameraPositionState) {
+    Card(
+        Modifier.padding(16.dp),
+        elevation = 4.dp
+    ) {
+        var mapLoaded by remember { mutableStateOf(false) }
+        var buildingFocused: Boolean? by remember { mutableStateOf(null) }
+        var focusedBuildingInvocationCount by remember { mutableIntStateOf(0) }
+        var activatedIndoorLevel: String? by remember { mutableStateOf(null) }
+        var activatedIndoorLevelInvocationCount by remember { mutableIntStateOf(0) }
+        var onMapClickCount by remember { mutableIntStateOf(0) }
+
+        var map: GoogleMap? by remember { mutableStateOf(null) }
+
+        fun updateIndoorLevel() {
+            activatedIndoorLevel = map!!.focusedBuilding?.run { levels.getOrNull(activeLevelIndex)?.name }
+        }
+
+        Box {
+            GoogleMap(
+                onMapClick = {
+                    onMapClickCount++
+                },
+                properties = remember {
+                    MapProperties(
+                        isBuildingEnabled = true,
+                        isIndoorEnabled = true
+                    )
+                },
+                cameraPositionState = cameraPositionState,
+                onMapLoaded = { mapLoaded = true },
+                indoorStateChangeListener = object : IndoorStateChangeListener {
+                    override fun onIndoorBuildingFocused() {
+                        super.onIndoorBuildingFocused()
+                        focusedBuildingInvocationCount++
+                        buildingFocused = (map!!.focusedBuilding != null)
+                        updateIndoorLevel()
+                    }
+
+                    override fun onIndoorLevelActivated(building: IndoorBuilding) {
+                        super.onIndoorLevelActivated(building)
+                        activatedIndoorLevelInvocationCount++
+                        updateIndoorLevel()
+                    }
+                }
+            ) {
+                MapEffect(Unit) { googleMap ->
+                    map = googleMap
+                    updateIndoorLevel()
+                    buildingFocused = (googleMap.focusedBuilding != null)
+                }
+            }
+
+            AnimatedVisibility(!mapLoaded, enter = fadeIn(), exit = fadeOut()) {
+                Box(
+                    Modifier.fillMaxSize(),
+                    contentAlignment = Alignment.Center
+                ) {
+                    CircularProgressIndicator()
+                }
+            }
+
+            @Composable
+            fun TextWithBackground(text: String, fontWeight: FontWeight = FontWeight.Medium) {
+                Text(
+                    modifier = Modifier.background(Color.White.copy(0.7f)),
+                    text = text,
+                    fontWeight = fontWeight,
+                    fontSize = 10.sp
+                )
+            }
+
+            Column(
+                modifier = Modifier.align(Alignment.BottomStart)
+            ) {
+                TextWithBackground(item.title, fontWeight = FontWeight.Bold)
+                TextWithBackground("Map loaded: $mapLoaded")
+                TextWithBackground("Map click count: $onMapClickCount")
+                TextWithBackground("Building focused: $buildingFocused")
+                TextWithBackground("Building focused invocation count: $focusedBuildingInvocationCount")
+                TextWithBackground("Indoor level: $activatedIndoorLevel")
+                TextWithBackground("Indoor level invocation count: $activatedIndoorLevelInvocationCount")
+            }
+        }
+    }
+}

app/src/main/res/values/strings.xml

@@ -32,4 +32,5 @@
   <string name="street_view">Street View</string>
   <string name="custom_location_button">Custom Location Button</string>
   <string name="accessibility_button">Accessibility</string>
+  <string name="maps_in_lazy_column_activity">Maps in LazyColumn</string>
 </resources>