> For the complete documentation index, see [llms.txt](https://create.cloud4wi.ai/dev-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://create.cloud4wi.ai/dev-hub/location-sdk/integrating-the-sdk/android/sdk-methods/get-device-id.md).

# Get Device Id

As soon as the SDK starts for the first time, a **Device ID** is assigned to that specific installation of your app.

> The Device ID assigned to an installation might change in case of rare events, for example if the local storage of the device gets erased.

The SDK provides two different ways to obtain the Device ID.

### Getting the Device ID through a Device ID listener

The first method to obtain the Device ID is to set a `IDeviceIdListener`, as shown in the example below. When a listener is set, the SDK immediately returns the Device ID through the `onDeviceIdAvailable()` callback if the Device ID is already available. Otherwise, it will call the callback method as soon as the ID is obtained.

> The best practice for an app that want to collect on a backend systems the Device ID assigned to each installation, is to set a `IDeviceIdListener` each time it starts. The mobile app would receive the Device ID each time and should always send it to the backend system. Then, the backend system should overwrite any previously stored value if the new received value is different.

{% tabs %}
{% tab title="Java" %}

```java
public class MainActivity extends Activity {

    private GeoUniq geoUniq;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.geoUniq = GeoUniq.getInstance(this);
        this.setDeviceIdListener();
    }

    /**
     * Sets a listener to received the ID assigned to this device
     */
    private void setDeviceIdListener(){

        this.geoUniq.setDeviceIdListener(new GeoUniq.IDeviceIdListener() {

            @Override
            public void onDeviceIdAvailable(String deviceId) {
                Log.d("GeoUniq", "Device ID received: "+deviceId);
            }
        });
    }
}
```

{% endtab %}
{% endtabs %}

### Getting the Device ID by calling an explicit class method

The second way is to call the `GeoUniq.getDeviceId()` method. This method returns the value of the Device ID if it has already been obtained or `null` if the Device ID has not been obtained yet.


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