> For the complete documentation index, see [llms.txt](https://documentation.sceenic.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.sceenic.co/synchronization-sdk/tutorials/android/android-java-kotlin.md). # Android - Java/Kotlin ## Overview Follow this step-by-step tutorial to implement the video playback Synchronization SDK. While the client-side SDK will take care of most of the functionality, in order to make this sample application work, you will need to use the API\_KEY provided to you. Full code samples can be found here * [Java sample application](https://bitbucket.org/svmt/samplesyncwatchtogether-java/src/master/) * [Kotlin sample application](https://bitbucket.org/svmt/samplesyncwatchtogether-kotlin/src/master/) ## Requirements To complete this guide successfully the following prerequisites are required: * [Android Studio](https://developer.android.com/studio) * A Sceenic account * Access key for sync SDK ## Authentication An `Access Token` is needed in order to allow a client to connect to a sync group. {% hint style="danger" %} **Note:** It is important that the client application does not request an Access Token directly from the backend. By doing that you risk exposing the API\_TOKEN and API\_SECRET. {% endhint %} ### Acquiring an Access Token {% tabs %} {% tab title="cUrl(Bash)" %} ```bash curl -iL --request GET --url https://YOUR_CAS_URL/sync/token --header 'auth-api-key: API_KEY' --header 'auth-api-secret: API_SECRET' ``` {% endtab %} {% endtabs %} The `Access Token` is a JWT token - more about jwt you can read - [here](https://en.wikipedia.org/wiki/JSON_Web_Token). A successful response will look like that: ``` { "token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9...." } ``` {% hint style="info" %} You can get your API\_KEY and API\_SECRET in your private area, [here](https://media.sceenic.co/). {% endhint %} {% hint style="warning" %} **Note:** Every Sync Token corresponds to one specific sync group only. To allow two different clients to connect to the same group, the clients need to use the same `Access Token`. {% endhint %} ## Create a project * Open the Android Studio and select **New Project** from the **File** menu * Select **Empty Activity** and click next * Choose Java or Kotlin as your programming language for the project * Configure your project's location, application, and package names * Set the minimum **SDK** version of the application to **21** or higher ## Add the sync SDK library to your project * Create (if it does not exist) in the project a **libs** directory under the **app** folder * Add the file **wtsyncsdk\_v....aar** to the **libs** folder * Edit the application's **build.gradle** file (in the app folder) with SDK {% tabs %} {% tab title="Build.gradle" %} ```kotlin android { // Required compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } // Required packagingOptions { exclude 'META-INF/DEPENDENCIES' exclude 'META-INF/LICENSE' exclude 'META-INF/LICENSE.txt' exclude 'META-INF/license.txt' exclude 'META-INF/NOTICE' exclude 'META-INF/NOTICE.txt' exclude 'META-INF/notice.txt' exclude 'META-INF/ASL2.0' exclude("META-INF/*.kotlin_module") } } dependencies { implementation files('libs/wtsyncsdk_v....aar') implementation 'androidx.core:core-ktx:1.7.0' } ``` {% endtab %} {% endtabs %} ### Permissions * Add the following permissions to the **AndroidManifest.xml** file under the **app/src/main** folder in the project above the application tag. ```kotlin ``` ## Instantiating the SDK * SDK builder - Call SyncSdkBuilder to instantiate the SDK. {% tabs %} {% tab title="Java" %} ```java mSyncSdk = new SyncSdk.SyncSdkBuilder() .accessToken(mAccessToken) // mAccessToken - authorization token .name(mDisplayName) // mDisplayName - username .syncListener(this) // this - SyncListener object .build(); ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk = SyncSdk.SyncSdkBuilder() .accessToken(mAccessToken) // mAccessToken - authorization token .name(mDisplayName) // mDisplayName - username .syncListener(this) // this - SyncListener object .build() ``` {% endtab %} {% endtabs %} * Start synchronization {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.startSync(); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.startSync() ``` {% endtab %} {% endtabs %} * Stop synchronization {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.stopSync(); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.stopSync() ``` {% endtab %} {% endtabs %} * Group play video {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.groupPlay(); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.groupPlay() ``` {% endtab %} {% endtabs %} * Group pause video {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.groupPause(); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.groupPause() ``` {% endtab %} {% endtabs %} * Group seek video {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.groupSeek(position); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.groupSeek(position) ``` {% endtab %} {% endtabs %} * Group seek success {% tabs %} {% tab title="Java" %} ```java if (mSyncSdk != null) { mSyncSdk.groupSeekSuccess(position); } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin mSyncSdk?.groupSeekSuccess(position) ``` {% endtab %} {% endtabs %} ## Managing synchronization logic The synchronization logic is managed using callbacks, using them you will be able to create the interaction you need. * In the sample application, you can see an example for implementing the necessary callbacks {% tabs %} {% tab title="Java" %} ```java public class MainActivity extends AppCompatActivity implements SyncListener { ... @Override public void onClientList(@NotNull List syncClients) { // remote sync client joined to the group, update ui using adapter // update ui with the list of connected clients in the same group } @Override public void onSetPlaybackRate(float rate) { // setting playback rate } @Override public void onPlaybackFromPosition(long position) { // playback from position // player.seekTo(position); } @Override public long onGetPlayerPosition() { // getting player position // Implement your logic to extract player position in miliseconds, // be sure that all clients connected to the same group extracts relevant // and from the same content timestamps(position) // return player.getCurrentPosition(); return 0L; } @Override public float onGetPlaybackRate() { // getting playback rate // Implement your logic to extract player rate/speed // return player.speed; return 0f; } @Override public void onSyncInfo(@NotNull SyncInfo syncInfo) { // information about synchronization's accuracy and delta // syncInfo.accuracy 0.0% - 100.0% // syncInfo.delta starts from 0L and describes how big is delay // in miliseconds, can be negative value } @Override public void onSyncGroupPlay() { // received an event onSyncGroupPlay() // play function should be called if its not playing already if (!player.isPlaying()) { player.play(); } } @Override public void onSyncGroupPause() { // received an event onSyncGroupPause() // pause function should be called if its still playing if (player.isPlaying()) { player.pause(); } } @Override public void onSyncGroupSeek(long position) { // received an event onSyncGroupSeek(long position) with position parameter // seek function should be called to the given position // works with VOD if (!player.isCurrentWindowLive()) { player.seekTo(position); } // Client should send success seek request every time onSyncGroupSeek called if (mSyncSdk != null) { mSyncSdk.groupSeekSuccess(position); } } @Override public void onSyncDisconnected() { // client has been disconnected from the group. All connections // will be closed. Clear ui and data } } ``` {% endtab %} {% tab title="Kotlin" %} ```kotlin class MainActivity : AppCompatActivity(), SyncListener { ... override fun onClientList(syncClients: List) { // remote client joined to the group, update ui using adapter // update ui with the list of connected clients in the same group } override fun onSetPlaybackRate(rate: Float) { // setting playback rate } override fun onPlaybackFromPosition(position: Long) { // playback from position // player.seekTo(position) } override fun onGetPlayerPosition(): Long { // getting player position // Implement your logic to extract player position in miliseconds, // be sure that all clients connected to the same group extracts relevant // and from the same content timestamps(position) // return player.getCurrentPosition() // Important! In case if content is Http Live Stream // Value of position shoulb be based on Program-Date-Time tag return 0L } override fun onGetPlaybackRate(): Float { // getting playback rate // Implement your logic to extract player rate/speed // return player.speed return 0f } override fun onSyncInfo(syncInfo: SyncInfo) // information about synchronization's accuracy and delta // syncInfo.accuracy 0.0% - 100.0% // syncInfo.delta starts from 0L and describes how big is delay // in miliseconds, can be negative value } override fun onSyncGroupPlay() { // received an event onSyncGroupPlay() // play function should be called player.play() } override fun onSyncGroupPause() { // received an event onSyncGroupPause() // pause function should be called player.pause() } override fun onSyncGroupSeek(position: Long) { // received an event onSyncGroupSeek(long position) with position parameter // seek function should be called to the given position // works with VOD if (!player.isCurrentWindowLive) { player.seekTo(position) } // Client should send success seek request every time onSyncGroupSeek called mSyncSdk?.groupSeekSuccess(position) } override fun onSyncDisconnected() { // client has been disconnected from the group. All connections will be closed. // clear ui and data } ``` {% endtab %} {% endtabs %} ## Running the application Once coding is finished, you should be able to run the application in the Android Studio emulator. You can view the complete Watch Together sample application here * [Java sample application](https://bitbucket.org/svmt/samplesyncwatchtogether-java/src/master/) * [Kotlin sample application](https://bitbucket.org/svmt/samplesyncwatchtogether-kotlin/src/master/) ## Support Need technical support? contact us at .