Multi-window support isn’t the only awesome new multitasking feature in Android 7.0 Nougat: Google has also added a secret new shortcut for quickly switching between the two most recently-used apps.
So why is this so useful? As I noted in Android 7.0 Nougat Tip: Use Two Apps Side-by-Side, the new split-screen view works great if you actually want two apps on screen at the same time and if both support the feature. But many apps don’t. And oftentimes, you really want to view both apps full-screen.
No worries, you can quickly switch between two apps in Android 7.0 Nougat. And it’s really easy, you just need to know the trick.
And that is, you just double-press the Overview (square) button. Doing so will instantly switch to the previously-used app. It’s like tapping ALT + TAB in Windows. But for Android.
To see it in action, open one app. Then press the Home (circle) button to go back to the home screen and launch another app. Now, double-press the Overview button repeatedly to go back and forth between the two.
You can always press the Overview button normally to view the Overview (recent apps) screen and choose a different app, of course. But then double-pressing the button will cycle between that app and whatever app is before it in the list.