> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/click-to-pay/integrate-d1-notifications/in-app-notifications-and-messaging.md).

# In-app notifications and messaging

Use the D1 SDK to register the issuer application for in-app notifications. You can also retrieve a message list and mark messages as read.

### Register the issuer application for notifications

D1 requires the issuer application to explicitly register with the messaging service to receive in-app notifications.

You perform this registration using the D1 SDK.

#### Flow

D1 delivers in-app notifications using push notifications.

<figure><img src="/spaces/62lLFDcmLCeqqwmy4Fee/files/U8FespQASKBjiweV3ZJq" alt=""><figcaption><p>In-app notification flow using push notifications.</p></figcaption></figure>

#### Register and unregister

After calling `D1Task.updatePushToken`, register for message notifications by calling `MessagingService.registerMessageNotification`.

To stop receiving message notifications, call `MessagingService.unregisterMessageNotification`.

{% hint style="info" %}
When using Click to Pay and the messaging service, call `D1Task.login()` first. Then call `D1Task.updatePushToken()`. Only then call `MessagingService.registerMessageNotification()`.
{% endhint %}

#### Integration flow

**Prerequisites :**

* SDK is properly initialised.
* Issuer App called D1 SDK login API.
* Issuer App updated the push token.

<figure><img src="/spaces/62lLFDcmLCeqqwmy4Fee/files/W0zAPM9xGdG8HrQw1R6b" alt=""><figcaption><p>Register and unregister for message notifications.</p></figcaption></figure>

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

```java
MessagingService messagingService = d1Task.getMessagingService();
messagingService.registerMessageNotification(new D1Task.Callback<Void>() {
    @Override
    public void onSuccess(Void data){
        // Proceed with the subsequent flows, for example, update UI.
    }
    @Override
    public void onError(@NonNull D1Exception exception){
        // Refer to D1 SDK Integration – Error Management section. 
    }
});

MessagingService messagingService = d1Task.getMessagingService();
messagingService.unregisterMessageNotification(new D1Task.Callback<Void>(){
    @Override
    public void onSuccess(Void unused){
        // Proceed with subsequent flows.
    }
    @Override
    public void onError(@NonNull D1Exception e){
        // Refer to D1 SDK Integration – Error Management section.
    }
});
```

{% endtab %}

{% tab title="iOS" %}

```objective-c
do {
    messagingService = try d1Task.messagingService()
} catch let error {
    // possible error: D1Error.Code.deviceEnvironmentUnsafe
}

messagingService.registerMessageNotification { error in
    if error == nil {
        // Proceed with subsequent flows.
    } else {
        // Refer to D1 SDK Integration – Error Management section.
    }
}

messagingService.unregisterMessageNotification { error in
    if error == nil {
        // Proceed with subsequent flows.
    } else {
        // Refer to D1 SDK Integration – Error Management section.
    }
}
```

{% endtab %}
{% endtabs %}

### Retrieve messages and mark them as read

#### Flow

<figure><img src="/spaces/62lLFDcmLCeqqwmy4Fee/files/12iZMW9znpa9GYen0UiK" alt=""><figcaption></figcaption></figure>

#### Integration flow

**Prerequisites :**

* SDK is properly initialised
* Issuer App called D1 SDK login API

<figure><img src="/spaces/62lLFDcmLCeqqwmy4Fee/files/xZc8Zl3DNOhEdOWndhfn" alt=""><figcaption><p>Retrieve a message list and mark messages as read.</p></figcaption></figure>

You can handle messages from [push notifications](https://thales-dis-dbp.stoplight.io/docs/d1-caas/tx0ctsp29oo0v-message-handling). You can also retrieve a message list by calling `MessagingService.getMessageList`.

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

```java
MessagingService messagingService = d1Task.getMessagingService();
D1Task.Callback<List<Message>> callback = new D1Task.Callback<List<Message>>() {
    @Override
    public void onSuccess(List<Message> messages) {
        // Proceed with subsequent flows. For example, show the list to the end user.
        for(Message message : messages) {
            String id = message.getMessageID();
            String title = message.getTitle();
            String content = message.getMessage();
            boolean isRead = message.isRead();
            String timeStamp = message.getTimeStamp();
        }
    }
    @Override
    public void onError(@NonNull D1Exception e) {
        // Refer to D1 SDK Integration – Error Management section.
    }
};
messagingService.getMessageList(callback);
```

{% endtab %}

{% tab title="iOS" %}

```objective-c
do {
    messagingService = try d1Task.messagingService()
} catch let error {
    // possible error: D1Error.Code.deviceEnvironmentUnsafe
}

messagingService.messageList { messageList, error in
    if let messageList = messageList {
        // Proceed with subsequent flows. For example, show the list to the end user.
        for message in messageList {
            let id = message.id // To be used for marking message as read.
            let title = message.title
            let content = message.message
            let isRead = message.isRead
            let timestamp = message.timestamp
        }
    } else if let error = error {
        // Refer to D1 SDK Integration – Error Management section.
    }
}
```

{% endtab %}
{% endtabs %}

After the end user views the messages, mark them as read by calling `MessagingService.markMessageListAsRead`.

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

```java
ArrayList<String> messageIDs = new ArrayList<>();
messageIDs.add("<#T##messageID1: String#>");
messageIDs.add("<#T##messageID2: String#>");

MessagingService messagingService = d1Task.getMessagingService();
D1Task.Callback<Void> callback = new D1Task.Callback<Void>() {
    @Override
    public void onSuccess(Void unused) {
        // Proceed with subsequent flows. For example, update UI.
    }
    @Override
    public void onError(@NonNull D1Exception e) {
        // Refer to D1 SDK Integration – Error Management section.
    }
};
messagingService.markMessageListAsRead(messageIDs, callback);
```

{% endtab %}

{% tab title="iOS" %}

```objective-c
do {
    messagingService = try d1Task.messagingService()
} catch let error {
    // possible error: D1Error.Code.deviceEnvironmentUnsafe
}

let ids = ["<#T##messageID1: String#>", "<#T##messageID2: String#>"]
messagingService.markMessageListAsRead(ids) { error in
    if error == nil {
        // Proceed with subsequent flows. For example, update UI.
    } else {
        // Refer to D1 SDK Integration – Error Management section.
    }
}
```

{% endtab %}
{% endtabs %}


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