How to Add Markers to A Google Map With Kotlin?

11 minutes read

To add markers to a Google Map using Kotlin, follow these steps:

  1. First, make sure you have included the necessary dependencies in your project's build.gradle file. Add the following lines to the dependencies block:
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implementation 'com.google.android.gms:play-services-maps:17.0.0'
implementation 'com.google.android.gms:play-services-location:18.0.0'
implementation 'com.google.android.gms:play-services:17.5.0'


  1. In your activity layout XML file, add a element to hold the map. Set the android:name attribute to "com.google.android.gms.maps.SupportMapFragment". Make sure you also provide a unique ID for the fragment.
  2. In your activity class, implement the OnMapReadyCallback interface. This will allow you to receive a callback when the map is ready to be used. Also, declare a reference to the GoogleMap object:
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class YourActivity : AppCompatActivity(), OnMapReadyCallback {

    private lateinit var googleMap: GoogleMap

    override fun onMapReady(map: GoogleMap) {
        googleMap = map
        // Perform any map initialization or marker addition here
    }
    
    // Rest of your activity code
}


  1. In the onCreate() method of your activity, obtain a reference to the map fragment and use the getMapAsync() method to register the callback:
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val mapFragment = supportFragmentManager.findFragmentById(R.id.mapFragment) as SupportMapFragment
mapFragment.getMapAsync(this)


  1. Inside the onMapReady callback, you can add markers to the map by creating instances of the MarkerOptions class, setting the desired location and other properties, and adding them to the googleMap object using the addMarker() method:
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val markerOptions = MarkerOptions()
    .position(LatLng(latitude, longitude))
    .title("Marker Title")
    .snippet("Marker Description")
googleMap.addMarker(markerOptions)


Replace latitude and longitude with the actual coordinates of the marker.

  1. Repeat step 5 for each marker you want to add to the map.


Important Note: Don't forget to request the necessary permissions and include the necessary checks for location services before using location-related features in your app.

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What is the LatLng class in Google Maps Kotlin?

The LatLng class in Google Maps Kotlin is a class that represents a pair of latitude and longitude coordinates. It is used to define and work with geographic locations on the Earth's surface. It provides methods to get and set the latitude and longitude values, as well as other utility methods for distance calculations and serialization. The LatLng class is commonly used in applications that require mapping and geolocation functionality with the Google Maps API in Kotlin.


What is the purpose of the InfoWindowAdapter interface in Google Maps?

The purpose of the InfoWindowAdapter interface in Google Maps is to customize the content and behavior of info windows displayed on a map. It provides methods that allow you to provide custom views for the info window, control the content and layout, and handle user interactions within the info window.


By implementing this interface and providing custom views, you can display any desired content in an info window, such as text, images, buttons, or even complex layouts. This allows you to enhance the user experience by providing more interactive and visually appealing info windows.


Additionally, the InfoWindowAdapter also enables you to handle user interactions within the info window, such as clicking on buttons or other views. This allows you to implement custom behaviors or actions based on the user's interaction with the info window.


Overall, the InfoWindowAdapter interface is a powerful tool for customizing and controlling the appearance and functionality of info windows in Google Maps.


What are the different types of markers available in Google Maps?

There are several different types of markers available in Google Maps:

  1. Default Marker: This is the standard red colored marker that Google Maps uses by default to mark a specific location.
  2. Custom Marker: Users can upload their own custom marker icons to differentiate their markers from the default marker. These can be any image or icon that represents the specific location.
  3. Info Window Marker: This type of marker displays an information window when clicked. It typically contains additional information or context about the marked location, such as a title, description, or even images.
  4. Cluster Marker: When multiple markers are located closely together, Google Maps automatically groups them into a single cluster marker. This allows users to see the general area where multiple locations are present, and zoom in for more details.
  5. Direction Marker: This type of marker can be used to display directions from one location to another on Google Maps. It helps users easily visualize a route between two points.
  6. Heatmap Marker: Heatmap markers are used to show the intensity or density of a particular phenomenon across an area. These markers are often used in data visualization to represent a concentration of data points.
  7. Street View Marker: This marker allows users to view a 360-degree street-level image of a specific location. When clicked, it opens up Street View mode, where users can explore the surroundings.


These are some of the common types of markers available in Google Maps, and each serves a specific purpose in enhancing the user experience and providing various functionalities.


What is the method to get the title of a marker in Kotlin?

In Kotlin, the title of a marker can be obtained using the title property of the marker object.


Here's an example of how to get the title of a marker in Kotlin:

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val marker = // your marker object

val markerTitle = marker.title

// Use the markerTitle as per your requirement


In the above code, markerTitle will contain the title of the marker. You can then use this value as needed in your application.


How to set a custom marker info window adapter using Kotlin?

To set a custom marker info window adapter in Kotlin, you can follow these steps:


Step 1: Create a custom layout for the info window. In your project's layout folder, create a new XML layout file (e.g., custom_info_window.xml) and design the layout according to your desired custom info window. For example:

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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/titleTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp" />

    <TextView
        android:id="@+id/snippetTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="14sp" />

</LinearLayout>


Step 2: In your activity or fragment, implement the GoogleMap.InfoWindowAdapter interface and override its two methods: getInfoWindow and getInfoContents. The getInfoWindow method is used to provide the custom info window view, and the getInfoContents method is used to provide the default info window view (if getInfoWindow returns null). For example:

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class CustomInfoWindowAdapter(private val context: Context) : GoogleMap.InfoWindowAdapter {
    private val inflater: LayoutInflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater

    override fun getInfoWindow(marker: Marker): View? {
        // Returning null here indicates that we are using the default info window view
        return null
    }

    override fun getInfoContents(marker: Marker): View {
        val view = inflater.inflate(R.layout.custom_info_window, null)

        val titleTextView = view.findViewById<TextView>(R.id.titleTextView)
        val snippetTextView = view.findViewById<TextView>(R.id.snippetTextView)

        titleTextView.text = marker.title
        snippetTextView.text = marker.snippet

        return view
    }
}


Step 3: In your activity or fragment that contains the map, set the custom info window adapter to the GoogleMap instance by calling setInfoWindowAdapter on the map object. For example:

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val mapFragment = supportFragmentManager.findFragmentById(R.id.mapFragment) as SupportMapFragment
mapFragment.getMapAsync { googleMap ->
    val customInfoWindowAdapter = CustomInfoWindowAdapter(context)
    googleMap.setInfoWindowAdapter(customInfoWindowAdapter)

    // Add markers to the map and show them with their custom info windows
    val markerOptions = MarkerOptions()
        .position(LatLng(37.7749, -122.4194))
        .title("Marker Title")
        .snippet("Marker Snippet")
    googleMap.addMarker(markerOptions).showInfoWindow()
}


Now, the Google Map markers added to the map will show the custom info window layout defined in custom_info_window.xml.


What is the default color of a marker in Google Maps using Kotlin?

In Google Maps using Kotlin, the default color of a marker is RED.

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