Implementation of feature querying on iOS

android/src/main/java/com/mapbox/mapboxgl/MapboxMapController.java

@@ -26,6 +26,9 @@
 
 import androidx.annotation.NonNull;
 
+import com.google.gson.Gson;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
 import com.mapbox.android.core.location.LocationEngine;
 import com.mapbox.android.core.location.LocationEngineCallback;
 import com.mapbox.android.core.location.LocationEngineProvider;
@@ -495,9 +498,13 @@ public void onCancel() {
 
         String[] layerIds = ((List<String>) call.argument("layerIds")).toArray(new String[0]);
 
-        String filter = (String) call.argument("filter");
-
-        Expression filterExpression = filter == null ? null : new Expression(filter);
+        List<Object> filter = call.argument("filter");
+        JsonElement jsonElement = filter == null ? null : new Gson().toJsonTree(filter);
+        JsonArray jsonArray = null;
+        if (jsonElement != null && jsonElement.isJsonArray()) {
+          jsonArray = jsonElement.getAsJsonArray();
+        }
+        Expression filterExpression = jsonArray == null ? null : Expression.Converter.convert(jsonArray);
         if (call.hasArgument("x")) {
           Double x = call.argument("x");
           Double y = call.argument("y");

example/lib/map_ui.dart

@@ -50,6 +50,7 @@ class MapUiBodyState extends State<MapUiBody> {
   bool _myLocationEnabled = true;
   bool _telemetryEnabled = true;
   MyLocationTrackingMode _myLocationTrackingMode = MyLocationTrackingMode.Tracking;
+  List<Object> _featureQueryFilter;
 
   @override
   void initState() {
@@ -86,6 +87,21 @@ class MapUiBodyState extends State<MapUiBody> {
     );
   }
 
+  Widget _queryFilterToggler() {
+    return FlatButton(
+      child: Text('filter zoo on click ${ _featureQueryFilter == null ? 'disabled' : 'enabled'}'),
+      onPressed: () {
+        setState(() {
+          if (_featureQueryFilter == null) {
+            _featureQueryFilter = ["==", ["get", "type"] , "zoo"];
+          } else {
+            _featureQueryFilter = null;
+          }
+        });
+      },
+    );
+  }
+
   Widget _compassToggler() {
     return FlatButton(
       child: Text('${_compassEnabled ? 'disable' : 'enable'} compasss'),
@@ -236,14 +252,15 @@ class MapUiBodyState extends State<MapUiBody> {
       myLocationRenderMode: MyLocationRenderMode.GPS,
       onMapClick: (point, latLng) async {
         print("Map click: ${point.x},${point.y}   ${latLng.latitude}/${latLng.longitude}");
-        List features = await mapController.queryRenderedFeatures(point, [],null);
+        print("Filter $_featureQueryFilter");
+        List features = await mapController.queryRenderedFeatures(point, [], _featureQueryFilter);
         if (features.length>0) {
           print(features[0]);
         }
       },
       onMapLongClick: (point, latLng) async {
         print("Map long press: ${point.x},${point.y}   ${latLng.latitude}/${latLng.longitude}");
-        List features = await mapController.queryRenderedFeatures(point, [],null);
+        List features = await mapController.queryRenderedFeatures(point, [], null);
         if (features.length>0) {
           print(features[0]);
         }
@@ -280,6 +297,7 @@ class MapUiBodyState extends State<MapUiBody> {
               Text('camera zoom: ${_position.zoom}'),
               Text('camera tilt: ${_position.tilt}'),
               Text(_isMoving ? '(Camera moving)' : '(Camera idle)'),
+              _queryFilterToggler(),
               _compassToggler(),
               _myLocationTrackingModeCycler(),
               _latLngBoundsToggler(),

ios/Classes/MapboxMapController.swift

@@ -118,6 +118,34 @@ class MapboxMapController: NSObject, FlutterPlatformView, MGLMapViewDelegate, Ma
                 style.localizeLabels(into: locale)
             }
             result(nil)
+        case "map#queryRenderedFeatures":
+            guard let arguments = methodCall.arguments as? [String: Any] else { return }
+            let layerIds = arguments["layerIds"] as? Set<String>
+            var filterExpression: NSPredicate?
+            if let filter = arguments["filter"] as? [Any] {
+                filterExpression = NSPredicate(mglJSONObject: filter)
+            }
+            var reply = [String: NSObject]()
+            var features:[MGLFeature] = []
+            if let x = arguments["x"] as? Double, let y = arguments["y"] as? Double {
+                features = mapView.visibleFeatures(at: CGPoint(x: x, y: y), styleLayerIdentifiers: layerIds, predicate: filterExpression)
+            }
+            if  let top = arguments["top"] as? Double,
+                let bottom = arguments["bottom"] as? Double,
+                let left = arguments["left"] as? Double,
+                let right = arguments["right"] as? Double {
+                features = mapView.visibleFeatures(in: CGRect(x: left, y: top, width: right, height: bottom), styleLayerIdentifiers: layerIds, predicate: filterExpression)
+            }
+            var featuresJson = [String]()
+            for feature in features {
+                let dictionary = feature.geoJSONDictionary()
+                if  let theJSONData = try? JSONSerialization.data(withJSONObject: dictionary, options: []),
+                    let theJSONText = String(data: theJSONData, encoding: .ascii) {
+                    featuresJson.append(theJSONText)
+                }
+            }
+            reply["features"] = featuresJson as NSObject
+            result(reply)
         case "map#setTelemetryEnabled":
             guard let arguments = methodCall.arguments as? [String: Any] else { return }
             let telemetryEnabled = arguments["enabled"] as? Bool

lib/src/controller.dart

@@ -597,7 +597,7 @@ class MapboxMapController extends ChangeNotifier {
   }
 
   Future<List> queryRenderedFeatures(
-      Point<double> point, List<String> layerIds, String filter) async {
+      Point<double> point, List<String> layerIds, List<Object> filter) async {
     try {
       final Map<Object, Object> reply = await _channel.invokeMethod(
         'map#queryRenderedFeatures',

pubspec.lock

@@ -1,13 +1,13 @@
 # Generated by pub
-# See https://www.dartlang.org/tools/pub/glossary#lockfile
+# See https://dart.dev/tools/pub/glossary#lockfile
 packages:
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.11"
+    version: "1.14.12"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -19,7 +19,7 @@ packages:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.1.8"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -40,4 +40,5 @@ packages:
     source: hosted
     version: "2.0.8"
 sdks:
-  dart: ">=2.0.0-dev.68.0 <3.0.0"
+  dart: ">=2.2.2 <3.0.0"
+  flutter: ">=1.10.0 <2.0.0"