Proximity app launcher

'Proximity app launcher' is a background service that monitors the proximity sensor.
When the screen is on and the sensor detects proximity, an app will be launched if the proximity still exists after a specified delay.
Any non-system app can be selected.
If enabled, 'Proximity app launcher' will turn on the screen on loss of proximity. This option increases standby battery consumption.

Note: for turning off the screen you will need to install a dedicated app, e.g. 'LockNow' or 'Off without lock'.