[android] Generate style code for symbol-sort-key

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/Property.java

@@ -110,6 +110,10 @@ public final class Property {
 
   // SYMBOL_Z_ORDER: Controls the order in which overlapping symbols in the same layer are rendered
 
+  /**
+   * If {@link SYMBOL_SORT_KEY} is set, sort based on that. Otherwise sort symbols by their position relative to the viewport.
+   */
+  public static final String SYMBOL_Z_ORDER_AUTO = "auto";
   /**
    * Symbols will be sorted by their y-position relative to the viewport.
    */
@@ -123,6 +127,7 @@ public final class Property {
    * Controls the order in which overlapping symbols in the same layer are rendered
    */
   @StringDef({
+      SYMBOL_Z_ORDER_AUTO,
       SYMBOL_Z_ORDER_VIEWPORT_Y,
       SYMBOL_Z_ORDER_SOURCE,
     })

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/PropertyFactory.java

@@ -1785,6 +1785,26 @@ public class PropertyFactory {
     return new LayoutPropertyValue<>("symbol-avoid-edges", value);
   }
 
+  /**
+   * Sorts features in ascending order based on this value. Features with a higher sort key will appear above features with a lower sort key wehn they overlap. Features with a lower sort key will have priority over other features when doing placement.
+   *
+   * @param value a Float value
+   * @return property wrapper around Float
+   */
+  public static PropertyValue<Float> symbolSortKey(Float value) {
+    return new LayoutPropertyValue<>("symbol-sort-key", value);
+  }
+
+  /**
+   * Sorts features in ascending order based on this value. Features with a higher sort key will appear above features with a lower sort key wehn they overlap. Features with a lower sort key will have priority over other features when doing placement.
+   *
+   * @param value a Float value
+   * @return property wrapper around Float
+   */
+  public static PropertyValue<Expression> symbolSortKey(Expression value) {
+    return new LayoutPropertyValue<>("symbol-sort-key", value);
+  }
+
   /**
    * Controls the order in which overlapping symbols in the same layer are rendered
    *

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/SymbolLayer.java

@@ -181,6 +181,18 @@ public class SymbolLayer extends Layer {
     return (PropertyValue<Boolean>) new PropertyValue("symbol-avoid-edges", nativeGetSymbolAvoidEdges());
   }
 
+  /**
+   * Get the SymbolSortKey property
+   *
+   * @return property wrapper value around Float
+   */
+  @NonNull
+  @SuppressWarnings("unchecked")
+  public PropertyValue<Float> getSymbolSortKey() {
+    checkThread();
+    return (PropertyValue<Float>) new PropertyValue("symbol-sort-key", nativeGetSymbolSortKey());
+  }
+
   /**
    * Get the SymbolZOrder property
    *
@@ -1113,6 +1125,10 @@ public class SymbolLayer extends Layer {
   @Keep
   private native Object nativeGetSymbolAvoidEdges();
 
+  @NonNull
+  @Keep
+  private native Object nativeGetSymbolSortKey();
+
   @NonNull
   @Keep
   private native Object nativeGetSymbolZOrder();

platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/testapp/style/SymbolLayerTest.java

@@ -140,6 +140,32 @@ public class SymbolLayerTest extends BaseLayerTest {
     assertEquals(layer.getSymbolAvoidEdges().getValue(), propertyValue);
   }
 
+  @Test
+  @UiThreadTest
+  public void testSymbolSortKeyAsConstant() {
+    Timber.i("symbol-sort-key");
+    assertNotNull(layer);
+    assertNull(layer.getSymbolSortKey().getValue());
+
+    // Set and Get
+    Float propertyValue = 0.3f;
+    layer.setProperties(symbolSortKey(propertyValue));
+    assertEquals(layer.getSymbolSortKey().getValue(), propertyValue);
+  }
+
+  @Test
+  @UiThreadTest
+  public void testSymbolSortKeyAsExpression() {
+    Timber.i("symbol-sort-key-expression");
+    assertNotNull(layer);
+    assertNull(layer.getSymbolSortKey().getExpression());
+
+    // Set and Get
+    Expression expression = number(Expression.get("undefined"));
+    layer.setProperties(symbolSortKey(expression));
+    assertEquals(layer.getSymbolSortKey().getExpression(), expression);
+  }
+
   @Test
   @UiThreadTest
   public void testSymbolZOrderAsConstant() {
@@ -148,7 +174,7 @@ public class SymbolLayerTest extends BaseLayerTest {
     assertNull(layer.getSymbolZOrder().getValue());
 
     // Set and Get
-    String propertyValue = SYMBOL_Z_ORDER_VIEWPORT_Y;
+    String propertyValue = SYMBOL_Z_ORDER_AUTO;
     layer.setProperties(symbolZOrder(propertyValue));
     assertEquals(layer.getSymbolZOrder().getValue(), propertyValue);
   }

platform/android/src/style/layers/symbol_layer.cpp

@@ -56,6 +56,11 @@ namespace android {
         return std::move(*convert<jni::Local<jni::Object<>>>(env, toSymbolLayer(layer).getSymbolAvoidEdges()));
     }
 
+    jni::Local<jni::Object<>> SymbolLayer::getSymbolSortKey(jni::JNIEnv& env) {
+        using namespace mbgl::android::conversion;
+        return std::move(*convert<jni::Local<jni::Object<>>>(env, toSymbolLayer(layer).getSymbolSortKey()));
+    }
+
     jni::Local<jni::Object<>> SymbolLayer::getSymbolZOrder(jni::JNIEnv& env) {
         using namespace mbgl::android::conversion;
         return std::move(*convert<jni::Local<jni::Object<>>>(env, toSymbolLayer(layer).getSymbolZOrder()));
@@ -500,6 +505,7 @@ namespace android {
             METHOD(&SymbolLayer::getSymbolPlacement, "nativeGetSymbolPlacement"),
             METHOD(&SymbolLayer::getSymbolSpacing, "nativeGetSymbolSpacing"),
             METHOD(&SymbolLayer::getSymbolAvoidEdges, "nativeGetSymbolAvoidEdges"),
+            METHOD(&SymbolLayer::getSymbolSortKey, "nativeGetSymbolSortKey"),
             METHOD(&SymbolLayer::getSymbolZOrder, "nativeGetSymbolZOrder"),
             METHOD(&SymbolLayer::getIconAllowOverlap, "nativeGetIconAllowOverlap"),
             METHOD(&SymbolLayer::getIconIgnorePlacement, "nativeGetIconIgnorePlacement"),

platform/android/src/style/layers/symbol_layer.hpp

@@ -32,6 +32,8 @@ public:
 
     jni::Local<jni::Object<jni::ObjectTag>> getSymbolAvoidEdges(jni::JNIEnv&);
 
+    jni::Local<jni::Object<jni::ObjectTag>> getSymbolSortKey(jni::JNIEnv&);
+
     jni::Local<jni::Object<jni::ObjectTag>> getSymbolZOrder(jni::JNIEnv&);
 
     jni::Local<jni::Object<jni::ObjectTag>> getIconAllowOverlap(jni::JNIEnv&);