Multi-Device Read Status Synchronization

In instant messaging services, a single user account may be logged in on multiple devices. While RC synchronizes message data across devices when Multi-Device Message Synchronization service is enabled, the read/unread status of messages in conversations is only stored locally on each device. Therefore, applications may need to synchronize the read/unread status of specified conversations from the user's currently logged-in device to other endpoints.

tip

For IMLib SDK versions ≤ 5.6.2, multi-device synchronization of read status for system conversations is not supported.

Initiating Conversation Read Status Synchronization

Interface Prototype

- (void)syncConversationReadStatus:(RCConversationType)conversationType
                          targetId:(NSString *)targetId
                              time:(long long)timestamp
                           success:(nullable void (^)(void))successBlock
                             error:(nullable void (^)(RCErrorCode nErrorCode))errorBlock;

Parameter Description

Parameter	Type	Description
conversationType	RCConversationType	Conversation type
targetId	NSString	Conversation targetId
timestamp	long long	Unix timestamp (in milliseconds) of the last read message
successBlock	Block	Success callback
errorBlock	Block	Failure callback

Sample Code

[[RCCoreClient sharedCoreClient] syncConversationReadStatus:ConversationType_PRIVATE targetId:@"targetId" time:1626422416809 success:^{

} error:^(RCErrorCode nErrorCode) {

}];

Receiving Multi-Device Read Status Synchronization Notifications

The IMLib SDK distributes an RCLibDispatchReadReceiptNotification when receiving read status synchronization notifications. At this point, the message status in the database has already been updated to "read". Applications can use this notification to update the conversation UI, marking messages before messageTime as read.

Registering Notification Observer

[[NSNotificationCenter defaultCenter]
    addObserver:self
    selector:@selector(didReceiveReadReceiptNotification:)
    name:RCLibDispatchReadReceiptNotification
    object:nil];

Implementing Notification Handler

The Notification's object is nil, and userInfo is an NSDictionary object.

- (void)didReceiveReadReceiptNotification:(NSNotification *)notification {

    RCConversationType conversationType = (RCConversationType)[notification.userInfo[@"cType"] integerValue];
    long long readTime = [notification.userInfo[@"messageTime"] longLongValue];
    NSString *targetId = notification.userInfo[@"tId"];
    NSString *senderUserId = notification.userInfo[@"fId"];
}

Parameter Description

userInfo object key values:

Key	Type	Description
cType	NSNumber	Conversation type
messageTime	NSNumber	Message timestamp (messages with timestamps ≤ this value are marked as read)
tId	NSString	Conversation targetId
fId	NSString	Message senderUserId