Sometimes You need to hand over your phone to your colleague for an emergent call, you may not know whether he/she browse your private photos or other files or emails, or your little kids want to play a game on your phone, you may be nervous because he/she may open some apps accidentally and may even delete some of your files inadvertently.
Only a few people know about the existence of a screen pinning feature which can help you prevent all the mayhem.
In short, screen pinning in Android Lollipop let you you enable your Android Lollipop device to only show a specific app’s screen. The device is temporally locked in this specific app, and you cannot access any other apps.
By default, screen pinning is not enabled in Android Lollipop.
Open the Settings app, tap Security, then tap Screen pinning—it’s located under the “Advanced” heading. Next, toggle the screen pinning toggle to the “on” position.
To use screen pinning, tap the Overview button (the square button in the lower right corner of your screen), and swipe up and down until you find the app you want to pin.
Once you find the app you want to pin, tap the Pin button—it’s a blue-green button with a white pushpin on it.
So not only for kids, the feature can be useful for keeping the prying and wandering people out as well, who for some reason can’t focus on the photo or message they are being shown and try to investigate the contents of the phone at the slightest chance they get.