Message Preview

Use message preview when your app needs a lightweight latest-message summary for a chat list, inbox row, or notification handoff. The SDK exposes preview data on channel and subchannel models after message preview is enabled for the network.

Message preview is configured outside these client SDK calls, typically through network settings. Client SDKs read the preview that is returned with channel or subchannel data; they do not enable the setting themselves.

Platform Surface

Surface	TypeScript	iOS	Android	Flutter
Channel preview	`channel.messagePreview`	`channel.messagePreview`	`channel.getMessagePreview()`	`channel.messagePreview`
Subchannel preview	`subChannel.messagePreview`	`subChannel.messagePreview`	`subChannel.getMessagePreview()`	Not exposed as a public preview object
Preview ID	`messagePreviewId`	`messagePreviewId`	`getMessagePreviewId()`	`messagePreviewId`
Preview data	`data`, `dataType`	`data`, `dataType`	`getData()`, `getDataType()`	`data`, `dataType`

Parameters

Parameter	Required	Description
`channelId`	Yes	Channel ID used to retrieve or observe the channel that contains the preview.
`subChannelId`	Yes for subchannel preview	Subchannel ID used to retrieve or observe a subchannel preview where the platform exposes it.
Preview setting	Yes	The network must have message preview enabled before new messages produce preview data.
`messagePreview` null handling	Yes	A channel or subchannel can return no preview when no eligible message exists, preview is disabled, or the preview has not been cached yet.

Read Channel Preview

Read the preview from the channel object you already use for channel lists. Treat the preview as optional and render a fallback for empty channels.

import { ChannelRepository } from '@amityco/ts-sdk';

const unsubscribe = ChannelRepository.getChannel(
  channelId,
  ({ data: channelSnapshot, loading, error }) => {
    if (error) {
      handleError(error);
      return;
    }

    if (!loading && channelSnapshot?.messagePreview) {
      renderResults({
        id: channelSnapshot.messagePreview.messagePreviewId,
        dataType: channelSnapshot.messagePreview.dataType,
        data: channelSnapshot.messagePreview.data,
        userId: channelSnapshot.messagePreview.user?.userId,
      });
    }
  },
);

unsubscribe();

token = channelRepository.getChannel(channelId).observe { liveObject, error in
    if let error {
        handleError(error)
        return
    }

    guard let preview = liveObject.snapshot?.messagePreview else { return }

    showSuccessMessage([
        "id": preview.messagePreviewId,
        "type": preview.dataType,
        "subChannelId": preview.subChannelId
    ])
}

val currentChannel = channel ?: return
val preview = currentChannel.getMessagePreview() ?: return

showSuccessMessage(
    mapOf(
        "id" to preview.getMessagePreviewId(),
        "type" to preview.getDataType(),
        "subChannelId" to preview.getSubChannelId(),
    ),
)

final fetchedChannel = await AmityChatClient.newChannelRepository()
    .getChannel(channelId);

final preview = fetchedChannel.messagePreview;

if (preview != null) {
  final previewId = preview.messagePreviewId;
  final previewType = preview.dataType;
  final previewData = preview.data;
}

Read Subchannel Preview

Use subchannel preview when your UI lists subchannels directly. Flutter currently exposes messagePreviewId on AmitySubChannel, but not the composed AmityMessagePreview object.

import { SubChannelRepository } from '@amityco/ts-sdk';

const unsubscribe = SubChannelRepository.getSubChannel(
  subChannelId,
  ({ data: subChannel, loading, error }) => {
    if (error) {
      handleError(error);
      return;
    }

    if (!loading && subChannel?.messagePreview) {
      renderResults(subChannel.messagePreview.messagePreviewId);
    }
  },
);

unsubscribe();

let subChannelRepository = AmitySubChannelRepository()

token = subChannelRepository.getSubChannel(withId: "sub-channel-id").observe { liveObject, error in
    if let error {
        handleError(error)
        return
    }

    guard let preview = liveObject.snapshot?.messagePreview else { return }
    showSuccessMessage(preview.messagePreviewId)
}

val subChannelRepository = AmityChatClient.newSubChannelRepository()

val disposable = subChannelRepository
    .getSubChannel(subChannelId)
    .subscribe(
        { subChannel ->
            val preview = subChannel.getMessagePreview()
            showSuccessMessage(preview?.getMessagePreviewId() ?: "")
        },
        { error -> handleGeneralError(error) },
    )

Preview Fields

Field	Description
`messagePreviewId`	ID of the message represented by the preview.
`dataType`	Message data type, such as text, image, file, video, audio, or custom.
`data`	Preview payload for the message data type. For text messages, this contains the text payload.
`channelId`	Channel that owns the previewed message.
`subChannelId`	Subchannel that owns the previewed message.
`subChannelName`	Subchannel display name where the platform exposes it.
`isDeleted`	Whether the previewed message is deleted. Availability depends on the network preview setting.
`user`	User object for the previewed message creator when the SDK has the user data.

Query Channels

Load channel lists that include preview data.

Query Messages

Load full message timelines when preview data is not enough.

Channel Unread Count

Combine previews with unread count and mention indicators.

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Fundamentals

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Release Notes

Migration Guides

Support

Platform Surface

Parameters

Read Channel Preview

Read Subchannel Preview

Preview Fields

Query Channels

Query Messages

Channel Unread Count

​Platform Surface

​Parameters

​Read Channel Preview

​Read Subchannel Preview

​Preview Fields

​Related Topics

Query Channels

Query Messages

Channel Unread Count

Platform Surface

Parameters

Read Channel Preview

Read Subchannel Preview

Preview Fields

Related Topics