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Using Google Maps in NativeScript

Today I’m going to show you show to do some cool things with Google maps in NativeScript using the nativescript-google-maps-sdk plugin…

Using Google Maps in NativeScript poster

Take control of your career. Build JavaScript mobile apps.

Today I’m going to show you show to do some cool things with Google maps in NativeScript using the nativescript-google-maps-sdk plugin.


Here's what we're covering today

  1. How to center the map
  2. Place a marker on the map
  3. Draw a polyline on the map
  4. How to remove markers and polylines

NOTES

  1. I will not be covering how to install and configure the plugin. For help with that refer to the documentation found here: https://github.com/dapriett/nativescript-google-maps-sdk.
  2. My demo is using a NativeScript + Angular template so how I get my map in the view might be a little different if you are using NativeScript Core or Vue. The code behind should be very similar though.

To do anything with the map we must get a reference to it in our code behind. Let’s see how to do that.


There is a mapReady event that you can listen for in your code behind. Here is my view.


<ActionBar title="Map Demo" class="action-bar">    
</ActionBar>

<GridLayout>
    <MapView (mapReady)="onMapReady($event)" iosOverflowSafeArea="true"></MapView>
</GridLayout>

NOTE: The iosOverflowSafeArea=“true” is important for iPhone 10+ to allow the map to fill in the safe area. By default it is set to false.

For a video about safe areas in NativeScript, take a look at the bottom of this post


See the difference?


iOS Overflow False

iOS Overflow True


Then in your code behind we need to add the handler for that event. This event will fire when the map has loaded.


    onMapReady = (event) => {
        let mapView = event.object as MapView;
	}

Now that we have the busy work done, now we can do some fun stuff!


NOTE: You can add all the code inside of the onMapReady event or split it out into methods and call the methods from inside of the onMapReady event, it is up to you. For simplicity, we’ll just code inside of the event.

By default the map will center on (0,0)…which is in the South Atlantic Ocean just off the coast of Africa. Sometimes you might want the map to center on a different point. 😁



Part 1

Let’s look at how to center the map on the United States

    onMapReady = (event) => {
        let mapView = event.object as MapView;

        const NA_CENTER_LATITUDE = 39.8283459;
        const NA_CENTER_LONGITUDE = -98.5816737;

        mapView.latitude = NA_CENTER_LATITUDE;
        mapView.longitude = NA_CENTER_LONGITUDE;
        mapView.zoom = 3;
	}

Screenshot with the MapView centered on the United States



Part 2

Let’s add a marker and customize it a little

    onMapReady = (event) => {
        let mapView = event.object as MapView;

        const NA_CENTER_LATITUDE = 39.8283459;
        const NA_CENTER_LONGITUDE = -98.5816737;

        mapView.latitude = NA_CENTER_LATITUDE;
        mapView.longitude = NA_CENTER_LONGITUDE;
        mapView.zoom = 3;

        let stLouisCoordinates = {
            latitude: 38.619081,
            longitude: -90.196846
        };

        let stLouisMarker = new Marker();
        stLouisMarker.position = Position.positionFromLatLng(stLouisCoordinates.latitude, stLouisCoordinates.longitude);
        stLouisMarker.title = "St. Louis, MO";
        stLouisMarker.snippet = "Go Cardinals!";
        stLouisMarker.color = "#6B8E23";
        mapView.addMarker(stLouisMarker);
	}

Screenshot with a marker on St. Louis in the MapView



Part 3

Drawing polylines is similar to placing a marker on the map but with multiple points

const US_COORDINATES: Array<USCoordinate> = [
    {
        name: "north-west",
        latitude: 48.893758,
        longitude: -126.051448
    },
    {
        name: "north-east",
        latitude: 47.133486,
        longitude: -68.145135
    },
    {
        name: "south-east",
        latitude: 25.218599,
        longitude: -80.818088
    },
    {
        name: "south-west",
        latitude: 32.661658,
        longitude: -116.872625
    },
    {
        name: "center-west",
        latitude: 38.948326,
        longitude: -123.729374
    }
];
    onMapReady = (event) => {
        let mapView = event.object as MapView;

        const NA_CENTER_LATITUDE = 39.8283459;
        const NA_CENTER_LONGITUDE = -98.5816737;

        mapView.latitude = NA_CENTER_LATITUDE;
        mapView.longitude = NA_CENTER_LONGITUDE;
        mapView.zoom = 3;

        let stLouisCoordinates = {
            latitude: 38.619081,
            longitude: -90.196846
        };

        let stLouisMarker = new Marker();
        stLouisMarker.position = Position.positionFromLatLng(stLouisCoordinates.latitude, stLouisCoordinates.longitude);
        stLouisMarker.title = "St. Louis, MO";
        stLouisMarker.snippet = "Go Cardinals!";
        stLouisMarker.color = "#6B8E23";
        mapView.addMarker(stLouisMarker);

        const polyline = new Polyline();

        US_COORDINATES.map((coordinates: USCoordinate) => {
            polyline.addPoint(Position.positionFromLatLng(coordinates.latitude, coordinates.longitude));
        });

        // REQUIRED! Used to connect polyline to start point
        polyline.addPoint(Position.positionFromLatLng(US_COORDINATES[0].latitude, US_COORDINATES[0].longitude));

        polyline.visible = true;
        polyline.width = 2;
        polyline.color = new Color("#DD00b3fd");
        polyline.geodesic = false;
        mapView.addPolyline(polyline);

	}

Screenshot polyline around the United States in the MapView



Part 4

Now let’s see how to clean up our map


	mapView.removeAllShapes();
	mapView.removeAllMarkers();

I hope this helps you when working with Google Maps in your NativeScript apps.



Here is a video where Dave Coffin shows how to use safe areas in iOS




Tyler is a full stack developer who has been focusing on NativeScript over the past few years. He enjoys helping others out by teaching and mentoring, as well as speaking at conferences.

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