Android
Sync Manager Getting Started

SyncManager for Android

SyncManager for Android is a SendBird Chat SDK add-on for chat data synchronization that allows you to reliably cache group channels and messages in your Android client app with minimal effort. When SyncManager is added to your client app, it listens to the events that happen in channels and messages in real-time and executes the background tasks to update the local cache with data queried from SendBird server.

Note: SyncManager for Android is only applicable to group channels.


Benefits

Simplified integration

SendBird SyncManager is designed to ensure quick and easy implementation that doesn’t require much effort. It can easily be added to your client app so that you are able to benefit from all the advantages of our Chat SDK for Android.

Better user experience

SyncManager implements local data caching, meaning that group channels and messages are cached in local storage for fast loading in unstable network environments as well as data retrieval in offline mode.


Requirements

The minimum requirements for SyncManager for Android are:

  • Android 4.0+ (API level 14)
  • Java 8+
  • SendBird Chat SDK for Android 3.0.96+

Try the sample app

Our sample app has the core features of SyncManager for Android. Download the app from our repository on GitHub to get an idea of how to integrate the SyncManager to the Chat SDK and your project.

Download Sample App

Note: The fastest way to see our SyncManager in action is to build your chat app on top of our sample app. Make sure to change the application ID of the sample app to your own. Go to the Create a SendBird application from your dashboard section to learn more.


Download SyncManager for Android

SendBird SyncManager currently supports iOS, Android, and JavaScript SDKs. You can download SyncManager for Android from our repository on GitHub.

Download SyncManager


Install SyncManager for Android

SyncManager for Android is installed via Gradle.

build.gradle
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repositories {
    maven { url "https://raw.githubusercontent.com/sendbird/sendbird-syncmanager-android/master/" }
}
dependencies {
    // SyncManager SDK for Android (Latest)
    implementation 'com.sendbird.sdk:sendbird-syncmanager:1.1.18'

    // Chat SDK for Android
    implementation 'com.sendbird.sdk:sendbird-android-sdk:3.0.118'
}

How it works

SyncManager is designed to simplify the process of integrating chat in your Android client app by leveraging local caching. While SendBird Chat SDK for Android is highly customizable with a number of atomic features, SyncManager facilitates SDK integration by managing most background operations needed to run chat in your Android client app.

Event-driven structure

SyncManager has an event-driven architecture that updates the chatting view based on data events. Events received through the WebSocket connection as well as processed data in the cache are delivered to the client app by the SyncManager’s collection handlers and can be leveraged when implementing your view.

Collection

As a key component that can be used for view implementation, the Collection holds items that comprise channel or message data. In your view, a collection instance can be binded to an event handler to subscribe to events. In the callbacks of the event handler, you can implement what jobs to execute when a specific type of event happens. The following shows a simple example of how you can create a channel collection and bind it to a collection event handler:

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ChannelCollectionHandler channelCollectionHandler = new ChannelCollectionHandler() {
    @Override
    public void onChannelEvent(ChannelCollection channelCollection, List<GroupChannel> list, ChannelEventAction channelEventAction) {
        switch (channelEventAction) {
            case INSERT:
                break;
            case UPDATE:
                break;
            case MOVE:
                break;
            case REMOVE:
                break;
            case CLEAR:
                break;
        }
    }
};

GroupChannelListQuery query = GroupChannel.createMyGroupChannelListQuery();

ChannelCollection channelCollection = new ChannelCollection(query);
channelCollection.setCollectionHandler(channelCollectionHandler);

Background sync

Background sync is a feature of SyncManager that automatically stores data fetched from SendBird server in the local cache. When a collection is created, the background sync process starts running with the given conditions. Background sync should follow the lifecycle of a connection: the pauseSync() method is called when a connection is lost and the resumeSync() method is called when a connection is established.

For example, even if only 2 out of 12 channels are cached, background sync feeds the uncached SendBird server data to the chatting view so that all 12 channels are displayed. In order for this to happen, the channel collection’s fetch() should be called, and the collection brings the insert event for the two channels from the cache. Then, the uncached 10 channels are synchronized through background sync. After synchronization is completed, another insert event is given for the uncached 10 channels. Through this process, all 12 channels are displayed in the view.

Real-time event sync

Real-time event sync is a feature of SyncManager that listens for real-time events received through the WebSocket connection. When an event arrives, SyncManager identifies it, stores it in the cache, and delivers it to the collection handler with the appropriate action such as insert or remove.

Offline mode

SyncManager ensures your client app is operational during offline mode. If background sync isn’t running because a connection with the server hasn’t been established, the view can display cached data provided by SyncManager. Once a connection is re-established, the resumeSync() resumes background sync for data synchronization.


Implementation guide

This section describes how to implement SyncManager in your Android client app.

Initialization

Initialize and set up the database for SyncManager as below:

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SendBirdSyncManager.Options options = new SendBirdSyncManager.Options.Builder()
                    .setMessageResendPolicy(SendBirdSyncManager.MessageResendPolicy.AUTOMATIC)
                    .setAutomaticMessageResendRetryCount(5)
                    .build();

SendBirdSyncManager.setup(context, userId, options, new CompletionHandler() {
    @Override
    public void onCompleted(SendBirdException e) {
        if (e != null) {    // Error occurred during setup.
            return;
        }
        // Setup succeeded.
    }
}); 
FieldTypeDescription

userId

string

Specifies the ID of the user.

options

SendBirdSyncManager.Options

Specifies the options for how SyncManager works.

handler

CompletionHandler

Called after the setup is completed.

The SendBirdSyncManager.Options has the following properties:

Property nameDescription

messageCollectionCapacity

Determines the maximum capacity of messages in a collection related to a chat view. Messages that exceed the maximum capacity are removed. Acceptable values are from 200 to 2,147,483,647. (Default: 2,147,483,647)

messageResendPolicy

Determines the policy for handling failed messages. If delivery of a message fails, SyncManager performs different actions based on the configured policy. Acceptable values are:
- none (default): removes the pending message.
- manual: stores the failed message in the local cache and updates the pending message state as failed.
- automatic: performs the same actions as manual, but also tries to automatically resend the failed message.

automaticMessageResendRetryCount

Determines the maximum number of attempts to resend a failed message. Resend attempts are stopped for messages that have been resent the maximum number of attempts and they remain as failed. The messageResendPolicy value must be set as automatic for this to be applicable. (Default: 2,147,483,647)

maxFailedMessageCountPerChannel

Determines the maximum number of failed messages allowed in a channel. SyncManager deletes the earliest failed message and delivers the remove event through the MessageCollectionHandler if the number of failed messages exceeds this limit. (Default: 20)

failedMessageRetentionDays

Determines the number of days to retain failed messages. Once failed messages have been retained for the retention period, they are automatically removed. (Default: 7)

Connection handling

When the Chat SDK is connected to SendBird server, SyncManager fetches the current user’s chat-related data from the server to update the local cache. This enables SyncManager to synchronize the local cache with the channel and message data.

Additional jobs, which detect changes in connection status and notify SyncManager, are needed when data is fetched from the server through the Chat SDK’s connection event handler: calling the resumeSync() and pauseSync() methods. The resumeSync() should be called in the onReconnectSucceeded() to run background processes for data synchronization when connected, whereas the pauseSync() should be called in the onReconnectStarted() to pause the background processes when disconnected. Adding and removing the connection handler is suggested to be done in onResume() and onPause().

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@Override
protected void onResume() {
    super.onResume();

    SendBird.addConnectionHandler(YOUR_CONNECTION_HANDLER_ID, new SendBird.ConnectionHandler() {
        @Override
        public void onReconnectStarted() {
            SendBirdSyncManager.getInstance().pauseSync();
        }

        @Override
        public void onReconnectSucceeded() {
            SendBirdSyncManager.getInstance().resumeSync();
        }

        @Override
        public void onReconnectFailed() {
        }
    });
}

@Override
protected void onPause() {
    super.onPause();

    SendBird.removeConnectionHandler(YOUR_CONNECTION_HANDLER_ID);
}

Note: The SendBird.removeAllConnectionHandlers() or SendBird.removeAllChannelHandlers() method shouldn’t be called because it not only removes the handlers you’ve added, but also the handlers internally managed by SyncManager.

Clear local cache

The cache can be cleared regardless of connection to SendBird server using the clearCache() method.

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SendBirdSyncManager.getInstance().clearCache();

Note: The clearCache() is designed for debugging purposes only. Using it for other purposes isn’t recommended.