# Authenticate a User

Before we can authenticate a user from our app, we need to create one. You can create a user in either of these **2** ways:

* Use the dev panel (the "Users" tab when you select an application) in the Mitter.io Dashboard
* Make an API call from your backend server

In this example, we’ll be creating a user from the Mitter.io Dashboard using the dev panel.

## Create users from the dashboard

Head over to the Mitter.io Dashboard and do the following:

* Select your application from the list
* In the left sidebar, click on the **Users** icon, and then click on **New User**
* Give a name for your user and create one

Since we’ll be creating a group chat channel in the upcoming steps, go ahead and create **2** or **3** more users with different names.

Now, select one of the users you’ve created and click on **Add Token**. This will create an access token for the user. Copy the access token and keep it handy.

Follow the same process for creating a channel. Just choose the channel type as **Group Chat** and add all the users that you created in the previous step. Once your channel is created, you’ll see a channel ID. Copy it and keep it handy as well.

## Add a user to your app

Go back to your Android project and navigate to your custom `Application` class.

First, you need to define a `UserAuth` object with the user details you acquired in the previous step.

{% tabs %}
{% tab title="Kotlin" %}
{% code title="MyApp.kt" %}

```kotlin
val userAuth = UserAuth(
    userId = "8ed92f3c-0696-4513-a842-085e3cee589e",
    userAuthToken = "eyJhbGciOiJIUzUxMiJ9.eyJpc3MiOiJtaXR0ZXItaW8iLCJ1c2VyVG9rZW5JZCI6ImJtRlI5bWNQaDhkQnJHaWIiLCJ1c2VydG9rZW4iOiJiM2dvY2ZhZ3ZyNWlrNHJkbXJlc29wNnNlcyJ9.dlE1QOYmUJpqoh1kORm3hEI3KbBM0v8kKZQnQQwXR6TZuFiCaDQrJMlp-2dgNP1CTYCPMFYoqGctRWQ5JyNiOQ"
)
```

{% endcode %}
{% endtab %}

{% tab title="Java" %}
{% code title="MyApp.java" %}

```java
UserAuth userAuth = new UserAuth(
    "8ed92f3c-0696-4513-a842-085e3cee589e",
    "eyJhbGciOiJIUzUxMiJ9.eyJpc3MiOiJtaXR0ZXItaW8iLCJ1c2VyVG9rZW5JZCI6ImJtRlI5bWNQaDhkQnJHaWIiLCJ1c2VydG9rZW4iOiJiM2dvY2ZhZ3ZyNWlrNHJkbXJlc29wNnNlcyJ9.dlE1QOYmUJpqoh1kORm3hEI3KbBM0v8kKZQnQQwXR6TZuFiCaDQrJMlp-2dgNP1CTYCPMFYoqGctRWQ5JyNiOQ"
);
```

{% endcode %}
{% endtab %}
{% endtabs %}

You can get the user ID from the list of users in the **Users** tab. Make sure that the ID and auth token both belong to the same user.

Now, just pass this `UserAuth` object to your previously configured `Mitter` object inside the `onCreate()` method in your `MyApp` class, like this:

{% tabs %}
{% tab title="Kotlin" %}
{% code title="MyApp.kt" %}

```kotlin
mitter = Mitter(
    context = this,
    mitterConfig = mitterConfig,
    userAuth = userAuth
)
```

{% endcode %}
{% endtab %}

{% tab title="Java" %}
{% code title="MyApp.java" %}

```java
mitter = new Mitter(
    this,
    mitterConfig,
    userAuth
);
```

{% endcode %}
{% endtab %}
{% endtabs %}

Your Android app is now fully configured to make calls to the Mitter.io Platform. Let’s test that out by fetching some basic information for the currently logged-in user.

## Fetch currently logged-in user details

Head over to your `MainActivity` and get a reference to the `Mitter` object inside the `onCreate()` method.

{% tabs %}
{% tab title="Kotlin" %}
{% code title="MainActivity.kt" %}

```kotlin
class MainActivity : AppCompatActivity() {

    private lateinit var mitter: Mitter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        mitter = (application as MyApp).mitter
    }
}
```

{% endcode %}
{% endtab %}

{% tab title="Java" %}
{% code title="MainActivity.java" %}

```java
public class MainActivity extends AppCompatActivity {
    private Mitter mitter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mitter = ((MyApp) getApplication()).mitter;
    }
}
```

{% endcode %}
{% endtab %}
{% endtabs %}

Now, before making any calls, you need to get access to the basic group objects:

* `Users`
* `Channels`
* `Messaging`

Inside your `onCreate()`, define **3** objects like this:

{% tabs %}
{% tab title="Kotlin" %}
{% code title="MainActivity.kt" %}

```kotlin
val users = mitter.Users()
val channels = mitter.Channels()
val messaging = mitter.Messaging()
```

{% endcode %}
{% endtab %}

{% tab title="Java" %}
{% code title="MainActivity.java" %}

```java
Mitter.Users users = mitter.new Users();
Mitter.Channels channels = mitter.new Channels();
Mitter.Messaging messaging = mitter.new Messaging();
```

{% endcode %}
{% endtab %}
{% endtabs %}

You’re now all set to make calls. Let’s test out our setup by making a call to fetch the currently logged-in user details.

You need to call the `getCurrentUser()` method on the `Users` object that you defined just now.

{% tabs %}
{% tab title="Kotlin" %}
{% code title="MainActivity.kt" %}

```kotlin
users.getCurrentUser(
    onValueAvailableCallback = object : Mitter.OnValueAvailableCallback<User> {
        override fun onError(apiError: ApiError) {
            Log.d("MSA", "Error while fetching user: $apiError")
        }

        override fun onValueAvailable(value: User) {
            Log.d("MSA", "User is: ${value.screenName.screenName}")
        }
    }
)
```

{% endcode %}
{% endtab %}

{% tab title="Java" %}
{% code title="MainActivity.java" %}

```java
users.getCurrentUser(new Mitter.OnValueAvailableCallback<User>() {
    @Override
    public void onValueAvailable(User user) {
        Log.d("MSA", "User is: "+ user.getScreenName().getScreenName());
    }

    @Override
    public void onError(ApiError apiError) {
        Log.d("MSA", "Error while fetching user: " + apiError);
    }
});
```

{% endcode %}
{% endtab %}
{% endtabs %}

If you’ve set everything up correctly, you should see something similar to this in your app’s logs:

```
D/MSA: User is: Jason
```