title: Check if downloads are active
body: <p>So I'm using Download Manager to download multiple files in my app. I need these files to finish downloading before starting a certain activity. How can I check if there are active downloads, so I can tell the user to wait until the downloads are finished. And then, when they are finished, I need to make a button visible. I've googled this, even tried some code myself(blindly) and nothing works. If somebody can nudge me in the right direction I'd be grateful.</p>