With Heads-up, any device can get the heads-up notifications introduced in the Android 5.0 “Lollipop”, no root required. But according to Addictivetips, this app is much more than just a backport. And according to the users, this app is way better than the original!
HIGHLIGHTS: Heads-up displays the latest notification as a floating popup, complete with full text and quick actions (4.1+). Works on everything running Android 3.1 and newer. You're in control: Heads-up has five pages of customization, so you'll get notified your way. Pocket detection – when you get a message, Heads-up turns the screen on if you take your phone out of the pocket! (Kind of like AcDisplay. Note: this causes a tiny increase in battery usage if you get a ton of notifications) Privacy on the lock screen (and in general - Heads-up doesn't even have internet permission, so it can't send your private data anywhere) Oh, and it's known to work on some smartwatches.
Heads-up is not a lockscreen app, so don't expect it behave like the Lollipop lockscreen.
LANGUAGES: Heads-up notifications is available in over 20 languages, thanks to an awesome team of translators. If you want to help translate, head to https://crowdin.com/project/heads-up
COMMON ISSUES: If no popups appear, please make sure that Heads-up shows up in the list of running services. If it doesn't, make sure you have enabled the service, and then reboot the phone.
If your device is running Android 4.2 or earlier, and you have other accessibility services running (such as Pushbullet), they might block Heads-up from receiving your notifications. Please try to disable them if Heads-up doesn't work.
Huawei, XIAOMI and MIUI users: please allow Heads-up to display popups under Settings > Apps > Downloaded > Heads-up. It might also be necessary to reset the app data/settings.
Uninstalling: If you find that the uninstall button is disabled, go to System Settings > Security > Device administrators > Heads-up, and tap Disable.
Other: Facebook Messenger, AcDisplay and PushBullet notification mirroring might conflict with Heads-up.
OPEN-SOURCE: Heads-up is open-source, licensed under GPL! That means you can make your own version of Heads-up, as long as the resulting app also is open-source. If you want a feature, theme or something else, head to: https://github.com/SimenCodes/heads-up/ If you experience any issues or have feature requests, please open an issue at: https://github.com/SimenCodes/heads-up/issues/ If the app crashes, please tap 'Report', then 'Send'. This makes it far easier to fix the issue.
Want new features before everyone else? Join the beta: https://play.google.com/apps/testing/codes.simen.l50notifications