public class MainActivity extends AppCompatActivity {
    private static final String TAG = MainActivity.class.getSimpleName();
    private Session session;
    private SignalMessageAdapter messageHistory;
    private EditText messageEditTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        messageEditTextView = findViewById(R.id.message_edit_text);
        ListView messageHistoryListView = findViewById(R.id.message_history_list_view);

        messageHistory = new SignalMessageAdapter(this);
        messageHistoryListView.setAdapter(messageHistory);

        messageEditTextView.setEnabled(false);

        session = new Session.Builder(this, VonageVideoSDKConfig.APP_ID, VonageVideoSDKConfig.SESSION_ID).build();
        session.setSessionListener(sessionListener);
        session.setSignalListener(signalListener);
        session.connect(VonageVideoSDKConfig.TOKEN);
    }
}