[ios] fixes #5128 selected property to MGLAnnotationView

platform/ios/app/MBXAnnotationView.m

@@ -25,4 +25,12 @@ - (void)setCenterColor:(UIColor *)centerColor {
     }
 }
 
+- (void)setSelected:(BOOL)selected animated:(BOOL)animated
+{
+    [super setSelected:selected animated:animated];
+
+    self.layer.borderColor = selected ? [UIColor blackColor].CGColor : [UIColor whiteColor].CGColor;
+    self.layer.borderWidth = selected ? 2.0 : 0;
+}
+
 @end

platform/ios/src/MGLAnnotationView.h

@@ -40,6 +40,12 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property (nonatomic, assign, getter=isFlat) BOOL flat;
 
+/**
+ Defaults to NO. Becomes YES when clicked on in the map view.
+ */
+@property (nonatomic, assign, getter=isSelected) BOOL selected;
+- (void)setSelected:(BOOL)selected animated:(BOOL)animated;
+
 /**
  Setting this property to YES will cause the annotation view to shrink as it approaches the horizon and grow as it moves away from the
  horizon when the associated map view is tilted. Conversely, setting this property to NO will ensure that the annotation view maintains

platform/ios/src/MGLAnnotationView.mm

@@ -37,6 +37,16 @@ - (void)setCenterOffset:(CGVector)centerOffset
     self.center = self.center;
 }
 
+- (void)setSelected:(BOOL)selected
+{
+    [self setSelected:selected animated:NO];
+}
+
+- (void)setSelected:(BOOL)selected animated:(BOOL)animated
+{
+    _selected = selected;
+}
+
 - (void)setCenter:(CGPoint)center
 {
     [self setCenter:center pitch:0];

platform/ios/src/MGLMapView.mm

@@ -3376,7 +3376,7 @@ - (void)selectAnnotation:(id <MGLAnnotation>)annotation animated:(BOOL)animated
         self.userTrackingMode = MGLUserTrackingModeNone;
     }
 
-    [self deselectAnnotation:self.selectedAnnotation animated:NO];
+    [self deselectAnnotation:self.selectedAnnotation animated:animated];
 
     // Add the annotation to the map if it hasn’t been added yet.
     MGLAnnotationTag annotationTag = [self annotationTagForAnnotation:annotation];
@@ -3401,6 +3401,8 @@ - (void)selectAnnotation:(id <MGLAnnotation>)annotation animated:(BOOL)animated
             positioningRect = annotationView.frame;
 
             [annotationView.superview bringSubviewToFront:annotationView];
+
+            [annotationView setSelected:YES animated:animated];
         }
     }
 
@@ -3554,6 +3556,19 @@ - (void)deselectAnnotation:(id <MGLAnnotation>)annotation animated:(BOOL)animate
     {
         // dismiss popup
         [self.calloutViewForSelectedAnnotation dismissCalloutAnimated:animated];
+
+        // deselect annotation view
+        MGLAnnotationTag annotationTag = [self annotationTagForAnnotation:annotation];
+        if (annotationTag != MGLAnnotationTagNotFound)
+        {
+            MGLAnnotationContext &annotationContext = _annotationContextsByAnnotationTag.at(annotationTag);
+            MGLAnnotationView *annotationView = annotationContext.annotationView;
+
+            if (annotationView)
+            {
+                [annotationView setSelected:NO animated:animated];
+            }
+        }
 
         // clean up
         self.calloutViewForSelectedAnnotation = nil;