Is it possible to utilize button-hold on mobile phone as a trigger for some programmed action? E.g. my app runs in background and it is programmed to open up if I hold both volume up and volume down buttons for 3 seconds.
I want to make iPhone/Android app. I haven't choose any framework yet, it's a question of technical possibility of such an idea, but I'll probably use objective-C/Swift as I have an iPhone.
I found an information for iOS on how to use events from volume buttons here, however it seems to be impossible to use events from power button or home button in the background, except from noticing that the app went from foreground to the background at home/power-button action.