I'm going to show you another way to implement FB video downloader in Android Studio.

First if you did not watch Papaya Coder's Facebook downloader video then go and watch it. Then look at my method.

Add FacebookUrlExtractor library.

 implementation 'com.github.Ashusolanki:FacebookUrlExtractor:0.0.1'

Add the JitPack repository

repositories {
    maven { url "https://jitpack.io" }
}

getAuthor();
getUrl();
getExt();
getFilename();
getQuality();
getDuration();

• https://github.com/Ashusolanki/FacebookUrlExtractor

This method only works when you give following type of URL: "https://www.facebook.com/102438284758534/videos/536904160301855"

That is

https://www.facebook.com/author or page name or id/videos/video id

If you want to contribute then do it!!