path: root/app/src/main/res/layout/activity_viewer.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="org.bienvenidoainternet.baiparser.ViewerActivity">

    <com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
    <pl.droidsonroids.gif.GifImageView
        android:id="@+id/gifView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <ProgressBar
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/downloadProgressBar"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>