Android turns the screen on and unlocks the phone when connecting or disconnecting from a charger. The SnooZy app takes care of this problem and keeps the screen off. I often use my phone for a minute, lock the screen, and then place it on a wireless charging plate. The phone then takes two–five seconds to start charging. When it does start, it unlocks the screen and turns it back on again to notify me that it started charging. So I’ve to put it down, stand there and wait for it to do its thing, and then turn the screen back off again. Annoying, right?
Every now and then, I solve a problem that has irritated me over some time. Today is one of those times.
Quoting my own answer to this problem on Stack Exchange’s Android Enthusiasts forum:
SnooZy Charger takes care of this. The free app (as in beer and speech) lets you manage behavior during charger connection and disconnection.
It requires no permissions, but does require you giving it device admin permissions. These permissions are only used to control device locking, as verifiable in its source-code. From quickly going through the app’s source code, it looks totally harmless and benign.
If the app doesn’t behave as you want, make sure to go through the Settings. For example, “Turn off screen only when locked” is enabled by default. This means that the app will not kick into effect if you’ve an on/off-button-press-lock delay or other related settings.
It works perfectly for me on a wireless charging pad and with micro-USB cable using a LG Nexus 4 device. I am very satisfied.
The app is great, though the user interface could need more work. I found the settings very unclear and had to test each of them to find out what they did. I spent ten minutes with the app’s strings and sent off a pull-request to the developer. Another noteworthy issue is #3: the screen will turn off when disconnecting a charger even when there’s an incoming call. Making it frustrating to interact with the touch-screen to answer the call.
The app works especially great with devices that use Qi wireless charging. These sometime turn the screen on and off several times through the night as charging pauses and resumes periodically.