I’m always confused by these kinds of switch buttons:
It takes me a couple of seconds to figure out if the button is displaying the current state (‘On’) or the possible action (switching to ‘On’). In this case, it’s meant to show the current state.
The use of such a toggle button requires:
- having 2 options only
- the 2 options to be mutually exclusive
The best known implementation of this button is actually the Play/Pause button:
It actually works in the exact opposite way: the button displays the possible action. Because we’re so well acquainted with this play/pause action, we’re always aware of its implied current state.
As a matter of fact, it makes sense because Play/Pause are actions, not states. The triangle and two-bars icons are read as ‘Play’ and ‘Pause’, not ‘Playing’ and ‘Pausing’.
That’s why the On/Off toggle switches display the current state: they are meant to be read as ‘It’s currently On’ and ‘It’s currently Off’, not ‘Switch to On’ and ‘Switch to Off’.
But it’s still unclear and not obvious. If you’re designing a web app, just use checkboxes. Or even better: Yes/No radio buttons.