Idling

Execute other tasks when menu is suspended.

When exiting from the main menu, either with '/' escape or by selecting an exit option if available. The menu enters an idle state. By default a blank screen doing nothing.

to return to menu again press select or '*' key

Often you want to enter other tasks on that state. There are multiple methods of doing so.

The efficient way

Just don't call the menu poll function, clear the screen and use it for whatever purpose you desire. This is efficient because the menu is not being polled and its completely inactive.

• This method can be used at any time and is independent of the menu state.
• The menu state is preserved
• Just start calling the poll function again to resume.

The easy way

Check the menu state and do alternative tasks when menu exited. The alternative tasks are only executed when exiting from the main menu or menu forced intro idle state.

example:

//on a device that uses poll
void loop() {
  nav.poll();
  if (nav.sleepTask) {
    //do your update here...
  }
}

  //...
  //on u8g2 or other devices that uses doInpu/doOutput instead of poll
  nav.doInput()
  if (nav.sleepTask) {
    u8g2.firstPage();
    do {
      u8g2.setCursor(0, 15);
      u8g2.print("suspended");
    } while ( u8g2.nextPage() );
  } else {
    if (nav.changed(0)) {
      u8g2.firstPage();
      do nav.doOutput(); while(u8g2.nextPage());
    }
  }
  //...

The only disadvantage of this method is that you are responsible to update the multiple output devices, in case you are using them. Otherwise its just fine.

The hard way

provide an idling function and do stuff inside it. This method is non blocking, if your function is non blocking and the alternative tasks are called when exiting from main menu.

start by pointing your alternative idle function

nav.idleTask=myFunct;//can do this on setup or when appropriate

myFunct will then be called when the menu is suspended/idling, and when exiting from main menu.

myFunct is of type idleFunct

result (*idleFunc)(menuOut& o,idleEvent);

your function will be called for each defined output device (passed it as first parameter) and with one of the following events as second parameter:

enum idleEvent {idleStart,idling,idleEnd};

Therefor it will be called at least 3 time per output device, one for each event. On some devices that require redraw the idling event might repeat for each poll until exit.

The preemptive way

call idleOn() to force menu into an idle state with the predefined idle function or idleOn(myFunct) for an alternative one.

call idleOff() to resume

menu enters idle state on next poll