Adapting an imperative map (Google Map, Mapbox Map, etc.) for a declarative UI such as Android Compose; below shows an example for a Mapbox map, in https://github.com/android/compose-samples/tree/e6994123804b976083fa937d3f5bf926da4facc5/Crane#crane-sample you will find an example for a Google Map
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package com.example.view | |
import androidx.compose.runtime.* | |
import androidx.compose.ui.Modifier | |
import androidx.compose.ui.platform.LocalContext | |
import androidx.compose.ui.platform.LocalLifecycleOwner | |
import androidx.compose.ui.viewinterop.AndroidView | |
import androidx.lifecycle.Lifecycle | |
import androidx.lifecycle.LifecycleEventObserver | |
import com.mapbox.geojson.Point | |
import com.mapbox.maps.* | |
import kotlinx.coroutines.launch | |
@Composable | |
fun Map(lat: Double, lng: Double, zoom: Double) { | |
MapboxMap(lat = lat, lng = lng, zoom = zoom) | |
} | |
@Composable | |
fun MapboxMap(lat: Double, lng: Double, zoom: Double) { | |
val map = rememberMapboxViewWithLifecycle() | |
MapboxMapContainer(map = map, lat = lat, lng = lng, zoom = zoom) | |
} | |
@Composable() | |
fun MapboxMapContainer(map: MapView, lat: Double, lng: Double, zoom: Double) { | |
val (isMapInitialized, setMapInitialized) = remember(map) { mutableStateOf(false) } | |
LaunchedEffect(map, isMapInitialized) { | |
if (!isMapInitialized) { | |
val mbxMap = map.getMapboxMap() | |
mbxMap.loadStyleUri(Style.OUTDOORS) { | |
mbxMap.centerTo(lat = lat, lng = lng, zoom = zoom) | |
setMapInitialized(true) | |
} | |
} | |
} | |
val coroutineScope = rememberCoroutineScope() | |
AndroidView(factory = { map }) { | |
coroutineScope.launch { | |
val mbxMap = it.getMapboxMap() | |
mbxMap.centerTo(lat = lat, lng = lng, zoom = zoom) | |
} | |
} | |
} | |
@Composable | |
private fun rememberMapboxViewWithLifecycle(): MapView { | |
val context = LocalContext.current | |
val opt = MapInitOptions(context, plugins = emptyList()) | |
val map = remember { MapView(context, opt) } | |
val observer = rememberMapboxViewLifecycleObserver(map) | |
val lifecycle = LocalLifecycleOwner.current.lifecycle | |
DisposableEffect(lifecycle) { | |
lifecycle.addObserver(observer) | |
onDispose { | |
lifecycle.removeObserver(observer) | |
} | |
} | |
return map | |
} | |
@Composable | |
private fun rememberMapboxViewLifecycleObserver(map: MapView): LifecycleEventObserver { | |
return remember(map) { | |
LifecycleEventObserver { _, event -> | |
when (event) { | |
Lifecycle.Event.ON_START -> map.onStart() | |
Lifecycle.Event.ON_STOP -> map.onStop() | |
Lifecycle.Event.ON_DESTROY -> map.onDestroy() | |
else -> Unit // nop | |
} | |
} | |
} | |
} | |
fun MapboxMap.centerTo(lat: Double, lng: Double, zoom: Double) { | |
val point = Point.fromLngLat(lng, lat) | |
val camera = CameraOptions.Builder() | |
.center(point) | |
.zoom(zoom) | |
.build() | |
setCamera(camera) | |
} |
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