fix(google-maps): allow for ground overlay image to be changed

src/dev-app/google-map/google-map-demo.html

@@ -101,4 +101,16 @@
     </label>
   </div>
 
+  <div>
+    <label for="ground-overlay-image">
+      Ground Overlay image
+
+      <select id="ground-overlay-image" (change)="groundOverlayUrlChanged($event)">
+        <option
+          *ngFor="let image of groundOverlayImages"
+          [value]="image.url">{{image.title}}</option>
+      </select>
+    </label>
+  </div>
+
 </div>

src/dev-app/google-map/google-map-demo.ts

@@ -66,7 +66,17 @@ export class GoogleMapDemo {
   circleOptions: google.maps.CircleOptions =
       {center: CIRCLE_CENTER, radius: CIRCLE_RADIUS, strokeColor: 'grey', strokeOpacity: 0.8};
   isGroundOverlayDisplayed = false;
-  groundOverlayUrl = 'https://angular.io/assets/images/logos/angular/angular.svg';
+  groundOverlayImages = [
+    {
+      title: 'Red logo',
+      url: 'https://angular.io/assets/images/logos/angular/angular.svg'
+    },
+    {
+      title: 'Black logo',
+      url: 'https://angular.io/assets/images/logos/angular/angular_solidBlack.svg'
+    }
+  ];
+  groundOverlayUrl = this.groundOverlayImages[0].url;
   groundOverlayBounds = RECTANGLE_BOUNDS;
 
   mapTypeId: google.maps.MapTypeId;
@@ -149,4 +159,8 @@ export class GoogleMapDemo {
   toggleGroundOverlayDisplay() {
     this.isGroundOverlayDisplayed = !this.isGroundOverlayDisplayed;
   }
+
+  groundOverlayUrlChanged(event: Event) {
+    this.groundOverlayUrl = (event.target as HTMLSelectElement).value;
+  }
 }

src/google-maps/map-ground-overlay/map-ground-overlay.spec.ts

@@ -57,11 +57,11 @@ describe('MapGroundOverlay', () => {
     expect(groundOverlaySpy.setMap).toHaveBeenCalledWith(mapSpy);
   });
 
-  it('has an error if required url or bounds are not provided', () => {
+  it('has an error if required bounds are not provided', () => {
     expect(() => {
       const fixture = TestBed.createComponent(TestApp);
       fixture.detectChanges();
-    }).toThrow(new Error('An image url is required'));
+    }).toThrow(new Error('Image bounds are required'));
   });
 
   it('exposes methods that provide information about the Ground Overlay', () => {
@@ -119,6 +119,32 @@ describe('MapGroundOverlay', () => {
     expect(addSpy).toHaveBeenCalledWith('dblclick', jasmine.any(Function));
     subscription.unsubscribe();
   });
+
+  it('should be able to change the image after init', () => {
+    const groundOverlaySpy = createGroundOverlaySpy(url, bounds, groundOverlayOptions);
+    const groundOverlayConstructorSpy =
+        createGroundOverlayConstructorSpy(groundOverlaySpy).and.callThrough();
+
+    const fixture = TestBed.createComponent(TestApp);
+    fixture.componentInstance.url = url;
+    fixture.componentInstance.bounds = bounds;
+    fixture.componentInstance.clickable = clickable;
+    fixture.componentInstance.opacity = opacity;
+    fixture.detectChanges();
+
+    expect(groundOverlayConstructorSpy).toHaveBeenCalledWith(url, bounds, groundOverlayOptions);
+    expect(groundOverlaySpy.setMap).toHaveBeenCalledWith(mapSpy);
+
+    groundOverlaySpy.setMap.calls.reset();
+    fixture.componentInstance.url = 'foo.png';
+    fixture.detectChanges();
+
+    expect(groundOverlaySpy.set).toHaveBeenCalledWith('url', 'foo.png');
+    expect(groundOverlaySpy.setMap).toHaveBeenCalledTimes(2);
+    expect(groundOverlaySpy.setMap).toHaveBeenCalledWith(null);
+    expect(groundOverlaySpy.setMap).toHaveBeenCalledWith(mapSpy);
+  });
+
 });
 
 @Component({

src/google-maps/map-ground-overlay/map-ground-overlay.ts

@@ -28,6 +28,7 @@ export class MapGroundOverlay implements OnInit, OnDestroy {
   private _eventManager = new MapEventManager(this._ngZone);
 
   private readonly _opacity = new BehaviorSubject<number>(1);
+  private readonly _url = new BehaviorSubject<string>('');
   private readonly _destroyed = new Subject<void>();
 
   /**
@@ -37,13 +38,19 @@ export class MapGroundOverlay implements OnInit, OnDestroy {
    */
   groundOverlay?: google.maps.GroundOverlay;
 
-  @Input() url!: string;  // Asserted in ngOnInit.
-
+  /** URL of the image that will be shown in the overlay. */
   @Input()
-  bounds!: google.maps.LatLngBounds|google.maps.LatLngBoundsLiteral;  // Asserted in ngOnInit.
+  set url(url: string) {
+    this._url.next(url);
+  }
 
-  @Input() clickable = false;
+  /** Bounds for the overlay. */
+  @Input() bounds: google.maps.LatLngBounds|google.maps.LatLngBoundsLiteral;
 
+  /** Whether the overlay is clickable */
+  @Input() clickable: boolean = false;
+
+  /** Opacity of the overlay. */
   @Input()
   set opacity(opacity: number) {
     this._opacity.next(opacity);
@@ -69,9 +76,6 @@ export class MapGroundOverlay implements OnInit, OnDestroy {
   constructor(private readonly _map: GoogleMap, private readonly _ngZone: NgZone) {}
 
   ngOnInit() {
-    if (!this.url) {
-      throw Error('An image url is required');
-    }
     if (!this.bounds) {
       throw Error('Image bounds are required');
     }
@@ -81,14 +85,16 @@ export class MapGroundOverlay implements OnInit, OnDestroy {
         // We'll bring it back in inside the `MapEventManager` only for the events that the
         // user has subscribed to.
         this._ngZone.runOutsideAngular(() => {
-          this.groundOverlay = new google.maps.GroundOverlay(this.url, this.bounds, options);
+          this.groundOverlay =
+              new google.maps.GroundOverlay(this._url.getValue(), this.bounds, options);
         });
         this._assertInitialized();
         this.groundOverlay.setMap(this._map.googleMap!);
         this._eventManager.setTarget(this.groundOverlay);
       });
 
       this._watchForOpacityChanges();
+      this._watchForUrlChanges();
     }
   }
 
@@ -150,6 +156,18 @@ export class MapGroundOverlay implements OnInit, OnDestroy {
     });
   }
 
+  private _watchForUrlChanges() {
+    this._url.pipe(takeUntil(this._destroyed)).subscribe(url => {
+      this._assertInitialized();
+      const overlay = this.groundOverlay;
+      overlay.set('url', url);
+
+      // Google Maps only redraws the overlay if we re-set the map.
+      overlay.setMap(null);
+      overlay.setMap(this._map.googleMap!);
+    });
+  }
+
   private _assertInitialized(): asserts this is {groundOverlay: google.maps.GroundOverlay} {
     if (!this._map.googleMap) {
       throw Error(

src/google-maps/testing/fake-google-map-utils.ts

@@ -241,15 +241,18 @@ export function createCircleConstructorSpy(circleSpy: jasmine.SpyObj<google.maps
 export function createGroundOverlaySpy(
     url: string, bounds: google.maps.LatLngBoundsLiteral,
     options?: google.maps.GroundOverlayOptions): jasmine.SpyObj<google.maps.GroundOverlay> {
+  const values: {[key: string]: any} = {url};
   const groundOverlaySpy = jasmine.createSpyObj('google.maps.GroundOverlay', [
     'addListener',
     'getBounds',
     'getOpacity',
     'getUrl',
     'setMap',
     'setOpacity',
+    'set',
   ]);
   groundOverlaySpy.addListener.and.returnValue({remove: () => {}});
+  groundOverlaySpy.set.and.callFake((key: string, value: any) => values[key] = value);
   return groundOverlaySpy;
 }
 

tools/public_api_guard/google-maps/google-maps.d.ts

@@ -94,7 +94,7 @@ export declare class MapGroundOverlay implements OnInit, OnDestroy {
     mapClick: Observable<google.maps.MouseEvent>;
     mapDblclick: Observable<google.maps.MouseEvent>;
     set opacity(opacity: number);
-    url: string;
+    set url(url: string);
     constructor(_map: GoogleMap, _ngZone: NgZone);
     getBounds(): google.maps.LatLngBounds;
     getOpacity(): number;