How to add Progress Bar in Splash Screen

I want to add a Progress Bar to my splash screen but my splash screen is not an Activity.
I have added windowBackground to my style

<style name="Theme" parent="Theme.MaterialComponents.Light.NoActionBar">

    <item name="android:windowBackground">@drawable/splash_image</item>
    <item name="android:statusBarColor">@color/white</item>

</style>

It is a PDF Viewer App which takes more time to load since it has to check for all the PDFs on the device

>Solution :

What you can do is setting the content view to another Layout and when you know the pdf is loaded you can show tha proper view or launch a new Activity.

In the onCreate method of your activity you have a line like this:

setContentView(R.layout.activity_main)

You could instead replace that with your new layout that you created that has a progress bar.

setContentView(R.layout.splash_screen)

And when you finished loading the pdf you can call the setContentView of your activity again and it will show everything.