处理点击事件

您可以让地图项图层响应用户 click 事件，以获取所点击边界的地点 ID 和地图项类型。下面这个示例地图展示了“国家/地区”图层的边界，该地图使用了事件处理脚本，用于为与所选国家/地区相关联的所点击多边形应用样式。

编写点击事件处理脚本

当地图项图层上发生点击事件时，Maps SDK for Android 会将 FeatureClickEvent 对象传递给事件处理脚本。使用 FeatureClickEvent 可获取点击的纬度和经度坐标，以及受点击影响的要素列表。

处理地图项图层事件

如需处理地图项图层上的事件，请按以下步骤操作。在此示例中，您为“国家/地区”要素图层定义了一个点击事件处理脚本，用于将红色填充应用于表示所选国家/地区的多边形。

当您调用 FeatureLayer.setFeatureStyle() 时，样式工厂函数会为地图项图层中的所有地图项设置样式。如需在事件处理脚本中更新地图项的样式，您必须调用 FeatureLayer.setFeatureStyle() 以设置所有地图项的更新后样式。

1. 按照开始使用中的步骤创建新的地图 ID 和地图样式（如果您尚未执行此操作）。请务必启用 Country（国家/地区）地图项图层。

2. 确保您的类实现了 FeatureLayer.OnFeatureClickListener。

3. 通过调用 FeatureLayer.addOnFeatureClickListener() 为要素点击事件注册事件处理脚本。

   Java

   private FeatureLayer countryLayer;
   
   @Override
   public void onMapReady(GoogleMap map) {
   
     // Get the COUNTRY feature layer.
     countryLayer = map.getFeatureLayer(new FeatureLayerOptions.Builder()
       .featureType(FeatureType.COUNTRY)
       .build());
   
     // Register the click event handler for the Country layer.
     countryLayer.addOnFeatureClickListener(this);
   
     // Apply default style to all countries on load to enable clicking.
     styleCountryLayer();
   }
   
   // Set default fill and border for all countries to ensure that they respond
   // to click events.
   private void styleCountryLayer() {
     FeatureLayer.StyleFactory styleFactory = (Feature feature) -> {
       return new FeatureStyle.Builder()
         // Set the fill color for the country as white with a 10% opacity.
         .fillColor(Color.argb(0.1, 0, 0, 0))
         // Set border color to solid black.
         .strokeColor(Color.BLACK)
         .build();
     };
   
     // Apply the style factory function to the country feature layer.
     countryLayer.setFeatureStyle(styleFactory);
   }

   Kotlin

   private var countryLayer: FeatureLayer? = null
   
   override fun onMapReady(googleMap: GoogleMap) {
     // Get the COUNTRY feature layer.
     countryLayer = googleMap.getFeatureLayer(FeatureLayerOptions.Builder()
       .featureType(FeatureType.COUNTRY)
       .build())
   
     // Register the click event handler for the Country layer.
     countryLayer?.addOnFeatureClickListener(this)
   
     // Apply default style to all countries on load to enable clicking.
     styleCountryLayer()
   }
   
   // Set default fill and border for all countries to ensure that they respond
   // to click events.
   private fun styleCountryLayer() {
     val styleFactory = FeatureLayer.StyleFactory { feature: Feature ->
       return@StyleFactory FeatureStyle.Builder()
         // Set the fill color for the country as white with a 10% opacity.
         .fillColor(Color.argb(0.1f, 0f, 0f, 0f))
         // Set border color to solid black.
         .strokeColor(Color.BLACK)
         .build()
     }
   
     // Apply the style factory function to the country feature layer.
     countryLayer?.setFeatureStyle(styleFactory)
   }

4. 为所选国家/地区应用红色填充颜色。只有可见地图项可供点击。

   Java

   @Override
   // Define the click event handler.
   public void onFeatureClick(FeatureClickEvent event) {
   
     // Get the list of features affected by the click using
     // getPlaceIds() defined below.
     List<String> selectedPlaceIds = getPlaceIds(event.getFeatures());
   
     if (!selectedPlaceIds.isEmpty()) {
       FeatureLayer.StyleFactory styleFactory = (Feature feature) -> {
         // Use PlaceFeature to get the placeID of the country.
         if (feature instanceof PlaceFeature) {
           if (selectedPlaceIds.contains(((PlaceFeature) feature).getPlaceId())) {
             return new FeatureStyle.Builder()
                 // Set the fill color to red.
                 .fillColor(Color.RED)
                 .build();
           }
         }
         return null;
       };
   
       // Apply the style factory function to the feature layer.
       countryLayer.setFeatureStyle(styleFactory);
     }
   }
   
   // Get a List of place IDs from the FeatureClickEvent object.
   private List<String> getPlaceIds(List<Feature> features) {
     List<String> placeIds = new ArrayList<>();
     for (Feature feature : features) {
       if (feature instanceof PlaceFeature) {
           placeIds.add(((PlaceFeature) feature).getPlaceId());
       }
     }
     return placeIds;
   }

   Kotlin

   // Define the click event handler.
   override fun onFeatureClick(event: FeatureClickEvent) {
   
     // Get the list of features affected by the click using
     // getPlaceIds() defined below.
     val selectedPlaceIds = getPlaceIds(event.getFeatures())
     if (!selectedPlaceIds.isEmpty()) {
         val styleFactory = FeatureLayer.StyleFactory { feature: Feature ->
             // Use PlaceFeature to get the placeID of the country.
             if (feature is PlaceFeature) {
                 if (selectedPlaceIds.contains((feature as PlaceFeature).getPlaceId())) {
                     return@StyleFactory FeatureStyle.Builder()
                         // Set the fill color to red.
                         .fillColor(Color.RED)
                         .build()
                 }
             }
             return@StyleFactory null
         }
   
         // Apply the style factory function to the feature layer.
         countryLayer?.setFeatureStyle(styleFactory)
     }
   }
   
   // Get a List of place IDs from the FeatureClickEvent object.
   private fun getPlaceIds(features: List<Feature>): List<String> {
     val placeIds: MutableList<String> = ArrayList()
     for (feature in features) {
         if (feature is PlaceFeature) {
             placeIds.add((feature as PlaceFeature).getPlaceId())
         }
     }
     return placeIds
   }