session-android/res/layout/activity_join_public_chat.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <android.support.design.widget.TabLayout
            style="@style/Session.DarkTabLayout"
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="@dimen/tab_bar_height" />

    </android.support.v4.view.ViewPager>

    <RelativeLayout
        android:id="@+id/loader"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#A4000000"
        android:visibility="gone"
        android:alpha="0">

        <com.github.ybq.android.spinkit.SpinKitView
            style="@style/SpinKitView.Large.ThreeBounce"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:layout_centerInParent="true"
            app:SpinKit_Color="@color/text" />

    </RelativeLayout>

</RelativeLayout>