Feature request: Add option for keeping screen on when showing a card

[brarcher]

There is an option to increase the screen brightness. However, if the screen times out it will still turn off. This feature is to hold a screen power lock so the screen does not turn off.

[sphh]

That would be really helpful, to have something like PassAndroid or Transportr: You can open any of these apps, select your boarding pass or travel connection and power off the screen. The next time you tap the power button, the last screen (either your boarding pass or your travel connection) shows up. No need to unlock your device. Very handy when boarding the plan or checking your connection. Would also be very handy when standing in the queue to the checkout!!

[devurandom]

@sphh Your suggestion is good! It was already previously requested in #242, where I added your hints about PassAndroid and Transportr.