[ios] Add iOS bindings and example for missing icons event. (#14302)

Added a new mapView delegate method that allows reload a style icon in case it couldn't load it from the style.

Added an iosapp test example.

platform/ios/app/MBXViewController.m

@@ -103,6 +103,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     MBXSettingsMiscellaneousToggleTwoMaps,
     MBXSettingsMiscellaneousLocalizeLabels,
     MBXSettingsMiscellaneousShowSnapshots,
+    MBXSettingsMiscellaneousMissingIcon,
     MBXSettingsMiscellaneousShouldLimitCameraChanges,
     MBXSettingsMiscellaneousShowCustomLocationManager,
     MBXSettingsMiscellaneousOrnamentsPlacement,
@@ -499,6 +500,7 @@ - (void)dismissSettings:(__unused id)sender
                 [NSString stringWithFormat:@"%@ Second Map", ([self.view viewWithTag:2] == nil ? @"Show" : @"Hide")],
                 [NSString stringWithFormat:@"Show Labels in %@", (_localizingLabels ? @"Default Language" : [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:[self bestLanguageForUser]])],
                 @"Show Snapshots",
+                @"Missing Icon",
                 [NSString stringWithFormat:@"%@ Camera Changes", (_shouldLimitCameraChanges ? @"Unlimit" : @"Limit")],
                 @"View Route Simulation",
                 @"Ornaments Placement",
@@ -746,6 +748,11 @@ - (void)performActionForSettingAtIndexPath:(NSIndexPath *)indexPath
                     [self performSegueWithIdentifier:@"ShowSnapshots" sender:nil];
                     break;
                 }
+                case MBXSettingsMiscellaneousMissingIcon:
+                {
+                    [self loadMissingIcon];
+                    break;
+                }
                 case MBXSettingsMiscellaneousShowCustomLocationManager:
                 {
                     [self performSegueWithIdentifier:@"ShowCustomLocationManger" sender:nil];
@@ -1718,6 +1725,19 @@ - (void)addVisibleAreaPolyline {
     [self.mapView addAnnotation:line];
 }
 
+- (void)loadMissingIcon
+{
+    self.mapView.centerCoordinate = CLLocationCoordinate2DMake(0, 0);
+    self.mapView.zoomLevel = 1;
+    NSURL *customStyleJSON = [[NSBundle mainBundle] URLForResource:@"missing_icon" withExtension:@"json"];
+    [self.mapView setStyleURL:customStyleJSON];
+}
+
+- (UIImage *)mapView:(MGLMapView *)mapView didFailToLoadImage:(NSString *)imageName {
+    UIImage *backupImage = [UIImage imageNamed:@"AppIcon"];
+    return backupImage;
+}
+
 - (void)printTelemetryLogFile
 {
     NSString *fileContents = [NSString stringWithContentsOfFile:[self telemetryDebugLogFilePath] encoding:NSUTF8StringEncoding error:nil];

platform/ios/app/missing_icon.json

@@ -0,0 +1,40 @@
+{
+    "version": 8,
+    "name": "Mapbox Streets",
+    "sprite": "mapbox://sprites/mapbox/streets-v8",
+    "glyphs": "mapbox://fonts/mapbox/{fontstack}/{range}.pbf",
+    "sources": {
+        "point": {
+            "type": "geojson",
+            "data": {
+                "type": "Feature",
+                "properties": {},
+                "geometry": {
+                    "type": "Point",
+                    "coordinates": [0, 0]
+                }
+            }
+        }
+    },
+    "layers": [{
+        "id": "bg",
+        "type": "background",
+        "paint": {
+            "background-color": "#f00"
+        }
+    }, {
+        "id": "point",
+        "type": "circle",
+        "source": "point",
+        "paint": {
+            "circle-radius": 100
+        }
+    }, {
+        "id": "icon",
+        "type": "symbol",
+        "source": "point",
+        "layout": {
+            "icon-image": "missing-icon"
+        }
+    }]
+}

platform/ios/ios.xcodeproj/project.pbxproj

@@ -459,6 +459,7 @@
 		96F3F73C1F57124B003E2D2C /* MGLUserLocationHeadingIndicator.h in Headers */ = {isa = PBXBuildFile; fileRef = 96F3F73B1F5711F1003E2D2C /* MGLUserLocationHeadingIndicator.h */; };
 		9C188C4F2242C95A0022FA55 /* MMEDate.m in Sources */ = {isa = PBXBuildFile; fileRef = 40834BBC1FE05D6E00C1BD0D /* MMEDate.m */; };
 		9C188C502242C96F0022FA55 /* MMEDate.h in Headers */ = {isa = PBXBuildFile; fileRef = 40834BC51FE05D6F00C1BD0D /* MMEDate.h */; };
+		A4F3FB1D2254865900A30170 /* missing_icon.json in Resources */ = {isa = PBXBuildFile; fileRef = A4F3FB1C2254865900A30170 /* missing_icon.json */; };
 		AC1B0916221CA14D00DB56C8 /* CLLocationManager+MMEMobileEvents.h in Headers */ = {isa = PBXBuildFile; fileRef = AC1B0914221CA14500DB56C8 /* CLLocationManager+MMEMobileEvents.h */; };
 		AC1B0917221CA14D00DB56C8 /* CLLocationManager+MMEMobileEvents.h in Headers */ = {isa = PBXBuildFile; fileRef = AC1B0914221CA14500DB56C8 /* CLLocationManager+MMEMobileEvents.h */; };
 		AC1B0918221CA14D00DB56C8 /* CLLocationManager+MMEMobileEvents.m in Sources */ = {isa = PBXBuildFile; fileRef = AC1B0915221CA14C00DB56C8 /* CLLocationManager+MMEMobileEvents.m */; };
@@ -1143,6 +1144,7 @@
 		96ED34DD22374C0900E9FCA9 /* MGLMapViewDirectionTests.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = MGLMapViewDirectionTests.mm; sourceTree = "<group>"; };
 		96F017292118FBAE00892778 /* MGLMapView_Experimental.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MGLMapView_Experimental.h; sourceTree = "<group>"; };
 		96F3F73B1F5711F1003E2D2C /* MGLUserLocationHeadingIndicator.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MGLUserLocationHeadingIndicator.h; sourceTree = "<group>"; };
+		A4F3FB1C2254865900A30170 /* missing_icon.json */ = {isa = PBXFileReference; lastKnownFileType = text.json; path = missing_icon.json; sourceTree = "<group>"; };
 		AC1B0914221CA14500DB56C8 /* CLLocationManager+MMEMobileEvents.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "CLLocationManager+MMEMobileEvents.h"; path = "../vendor/mapbox-events-ios/MapboxMobileEvents/CLLocationManager+MMEMobileEvents.h"; sourceTree = "<group>"; };
 		AC1B0915221CA14C00DB56C8 /* CLLocationManager+MMEMobileEvents.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = "CLLocationManager+MMEMobileEvents.m"; path = "../vendor/mapbox-events-ios/MapboxMobileEvents/CLLocationManager+MMEMobileEvents.m"; sourceTree = "<group>"; };
 		AC518DFD201BB55A00EBC820 /* MGLTelemetryConfig.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MGLTelemetryConfig.h; sourceTree = "<group>"; };
@@ -1883,6 +1885,7 @@
 			children = (
 				353BAEF51D646370009A8DA9 /* amsterdam.geojson */,
 				DA1DC96C1CB6C6CE006E619F /* points.geojson */,
+				A4F3FB1C2254865900A30170 /* missing_icon.json */,
 				DA1DC96D1CB6C6CE006E619F /* polyline.geojson */,
 				1F26B6C220E1A351007BCC21 /* simple_route.json */,
 				DA1DC96F1CB6C6CE006E619F /* threestates.geojson */,
@@ -2932,6 +2935,7 @@
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
 			knownRegions = (
+				English,
 				en,
 				Base,
 				"zh-Hans",
@@ -3001,6 +3005,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				DD4823771D94AE6C00EB71B7 /* numeric_filter_style.json in Resources */,
+				A4F3FB1D2254865900A30170 /* missing_icon.json in Resources */,
 				DA1DC9701CB6C6CE006E619F /* points.geojson in Resources */,
 				353BAEF61D646370009A8DA9 /* amsterdam.geojson in Resources */,
 				DA1DC9711CB6C6CE006E619F /* polyline.geojson in Resources */,

platform/ios/src/MGLMapView.mm

@@ -6821,6 +6821,20 @@ void onDidBecomeIdle() override {
     void onDidFinishLoadingStyle() override {
         [nativeView didFinishLoadingStyle];
     }
+
+    void onStyleImageMissing(const std::string& imageIdentifier) override {
+        NSString *imageName = [NSString stringWithUTF8String:imageIdentifier.c_str()];
+
+        if ([nativeView.delegate respondsToSelector:@selector(mapView:didFailToLoadImage:)]) {
+            UIImage *imageToLoad = [nativeView.delegate mapView:nativeView didFailToLoadImage:imageName];
+
+            if (imageToLoad) {
+                auto image = [imageToLoad mgl_styleImageWithIdentifier:imageName];
+                nativeView.mbglMap.getStyle().addImage(std::move(image));
+            }
+
+        }
+    }
 
     mbgl::gl::ProcAddress getExtensionFunctionPointer(const char* name) override {
         static CFBundleRef framework = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.opengles"));

platform/ios/src/MGLMapViewDelegate.h

@@ -275,6 +275,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)mapView:(MGLMapView *)mapView didFinishLoadingStyle:(MGLStyle *)style;
 
+- (nullable UIImage *)mapView:(MGLMapView *)mapView didFailToLoadImage:(NSString *)imageName;
+
 #pragma mark Tracking User Location
 
 /**

platform/ios/test/MGLMapViewDelegateIntegrationTests.swift

@@ -96,4 +96,6 @@ extension MGLMapViewDelegateIntegrationTests: MGLMapViewDelegate {
     func mapView(_ mapView: MGLMapView, shouldChangeFrom oldCamera: MGLMapCamera, to newCamera: MGLMapCamera, reason: MGLCameraChangeReason) -> Bool { return false }
 
     func mapViewUserLocationAnchorPoint(_ mapView: MGLMapView) -> CGPoint { return CGPoint(x: 100, y: 100) }
+
+    func mapView(_ mapView: MGLMapView, didFailToLoadImage imageName: String) -> UIImage? { return nil }
 }