Most download operations use the standard Android download manager, which provides developers with a robust and reliable solution. A few popular examples that make use of it include the Play Store, Chrome and the Xposed Installer. (If you're curious, the "Downloads" app on your phone provides an interface for viewing files that have been downloaded using the Android download manager.)

If you want to view the progress of an ongoing download, you'd usually have to pull down the notification bar to do so. This can be distracting, and causes the current activity to lose focus (especially noticeable if you're playing a quick game while waiting for your download to complete). Fortunately, XDA Recognized Contributor C3C076 wrote an Xposed module that allows you to take a quick glance at the current download's progress, in a very unobstructive manner.

Statusbar Download Progress acts similarly to battery bars, which you might be familiar with. It displays a line on top of your status bar, filling it horizontally as your download progresses. You can also pick the progress bar's color, mode (choose between the status bar's top and bottom edges) and margin.

If you want to give it a shot, make sure you've got the Xposed Framework installed, then visit the Statusbar Download Progress forum thread to try the module out.