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Get channels

The client SDK generates channels in the local database based on sent and received messages. Retrieve the channel list from the local database.

Get the channel list​

Retrieve channels from the local database with pagination. Channels are sorted by time (newest first), with pinned channels at the top.

Method​

Dart
static Future\<int\> getChannels(GetChannelsParams params, OprationHandler\<List\<BaseChannel\\>> handler);

Parameters​

ParameterTypeDescription
paramsGetChannelsParamsQuery parameters
handlerOprationHandler\<List\<BaseChannel\\>>Result callback returning the channel list

GetChannelsParams properties​

PropertyTypeDefaultDescription
identifiersList\<ChannelIdentifier\>RequiredChannel identifiers including type and ID
startTimeint0Timestamp (ms). Retrieves channels older than this time. Pass 0 for the latest. For pagination, pass the operationTime of the last channel from the previous page.
countint20Page size (0 < count ≤ 50)

ChannelIdentifier properties​

PropertyTypeDescription
channelTypeChannelTypeChannel type
channelIdStringChannel ID
subChannelIdString?Subchannel ID (community channels only)

Code example​

Dart
final params = GetChannelsParams(
  identifiers: [
    ChannelIdentifier(channelType: ChannelType.direct, channelId: 'user1'),
    ChannelIdentifier(channelType: ChannelType.group, channelId: 'group1'),
  ],
  startTime: 0,
  count: 20,
);

int? ret = await BaseChannel.getChannels(params, (List\<BaseChannel\>? channels, NCError? error) {
  if (error == null || error.isSuccess) {
    print('Channel count: ${channels?.length}');
  } else {
    print('Failed, error code: ${error.code}');
  }
});

Reload a channel​

Reload the latest details for a specific channel from the local database. This is a BaseChannel instance method.

Method​

Dart
Future\<int\> reload(OprationHandler\<BaseChannel\> handler);

Code example​

Dart
BaseChannel channel = ...;

int? ret = await channel.reload((BaseChannel? updated, NCError? error) {
  if (error == null || error.isSuccess) {
    print('Unread count: ${updated?.unreadCount}');
  }
});

Get channels with unread messages​

Retrieve channels that have unread messages. Supports direct, group, and system channels. Channels are sorted by time (newest first) with pinned channels at the top.

Method​

Dart
static Future\<int\> getUnreadChannels(List\<ChannelType\> types, OprationHandler\<List\<BaseChannel\\>> handler);

Code example​

Dart
final types = [ChannelType.direct, ChannelType.group, ChannelType.system];

int? ret = await BaseChannel.getUnreadChannels(types, (List\<BaseChannel\>? channels, NCError? error) {
  if (error == null || error.isSuccess) {
    print('Channels with unread messages: ${channels?.length}');
  }
});

FAQ​

Q: After reinstalling the app, the channel list is empty or partially missing?

A: The channel list is stored in the SDK's local database, which is cleared when the app is uninstalled. If missed message compensation is enabled, logging in on a new device triggers compensation to retrieve some historical channels (default: current day). To extend the compensation period (up to 7 days), submit a ticket. Setting a long period may cause processing pressure on clients with high message volumes.

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