chore : Centre camera on new location while recomposition

maps-app/src/androidTest/java/com/google/maps/android/compose/RecompositionActivityTests.kt

@@ -0,0 +1,68 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.maps.android.compose
+
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.performClick
+import com.google.android.gms.maps.model.CameraPosition
+import org.junit.Assert.assertNotEquals
+import org.junit.Rule
+import org.junit.Test
+
+class RecompositionActivityTests {
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    @Test
+    fun testChangeLocationButton_MovesCameraToNewLocation() {
+        check(hasValidApiKey) { "Maps API key not specified" }
+        val initialPosition = singapore
+        val cameraPositionState = CameraPositionState(
+            position = CameraPosition.fromLatLngZoom(initialPosition, 11f)
+        )
+
+        composeTestRule.setContent {
+            RecompositionActivity().GoogleMapView(
+                modifier = Modifier.fillMaxSize(),
+                cameraPositionState = cameraPositionState
+            )
+        }
+
+        // Verify initial camera target is centered at Singapore
+        initialPosition.assertEquals(cameraPositionState.position.target)
+
+        // Click the "Change Location" button
+        composeTestRule.onNodeWithText("Change Location")
+            .assertIsDisplayed()
+            .performClick()
+
+        // Wait until the camera target moves away from the initial position
+        composeTestRule.waitUntil(timeout5) {
+            cameraPositionState.position.target != initialPosition
+        }
+
+        // Wait until the camera animation has completed
+        composeTestRule.waitUntil(timeout5) {
+            !cameraPositionState.isMoving
+        }
+
+        // Verify that the camera has actually moved to a new location
+        assertNotEquals(initialPosition, cameraPositionState.position.target)
+    }
+}

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

@@ -29,12 +29,17 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import com.google.android.gms.maps.CameraUpdateFactory
 import com.google.android.gms.maps.model.Marker
 import com.google.maps.android.compose.theme.MapsComposeSampleTheme
-import kotlin.random.Random
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
 
 private const val TAG = "RecompositionActivity"
+private val singaporeLocations = listOf(singapore, singapore2, singapore3)
 
 /**
  * This is a sample activity showcasing how the recomposition works. The location is changed
@@ -71,11 +76,11 @@ class RecompositionActivity : ComponentActivity() {
         content: @Composable () -> Unit = {},
     ) {
         val markerState = rememberUpdatedMarkerState(position = singapore)
+        val coroutineScope = rememberCoroutineScope()
+        var animationJob by remember { mutableStateOf<Job?>(null) }
 
-        val uiSettings by remember { mutableStateOf(MapUiSettings(compassEnabled = false)) }
-        val mapProperties by remember {
-            mutableStateOf(MapProperties(mapType = MapType.NORMAL))
-        }
+        val uiSettings = remember { MapUiSettings(compassEnabled = false) }
+        val mapProperties = remember { MapProperties(mapType = MapType.NORMAL) }
 
         val mapVisible by remember { mutableStateOf(true) }
         if (mapVisible) {
@@ -88,12 +93,14 @@ class RecompositionActivity : ComponentActivity() {
                     Log.d(TAG, "POI clicked: ${it.name}")
                 }
             ) {
-                val markerClick: (Marker) -> Boolean = {
-                    Log.d(TAG, "${it.title} was clicked")
-                    cameraPositionState.projection?.let { projection ->
-                        Log.d(TAG, "The current projection is: $projection")
+                val markerClick: (Marker) -> Boolean = remember(cameraPositionState) {
+                    { marker ->
+                        Log.d(TAG, "${marker.title} was clicked")
+                        cameraPositionState.projection?.let { projection ->
+                            Log.d(TAG, "The current projection is: $projection")
+                        }
+                        false
                     }
-                    false
                 }
 
                 Marker(
@@ -106,12 +113,13 @@ class RecompositionActivity : ComponentActivity() {
             }
             Column {
                 Button(onClick = {
-                    val randomValue = Random.nextInt(3)
-                    markerState.position = when (randomValue) {
-                        0 -> singapore
-                        1 -> singapore2
-                        2 -> singapore3
-                        else -> singapore
+                    val newPosition = (singaporeLocations - markerState.position).random()
+                    markerState.position = newPosition
+                    animationJob?.cancel()
+                    animationJob = coroutineScope.launch {
+                        cameraPositionState.animate(
+                            CameraUpdateFactory.newLatLng(newPosition)
+                        )
                     }
                 }) {
                     Text("Change Location")