Beginning Flutter: 20 Switch
In this video, we review Switch. The widgets themselves do not actually have a state. Instead, the value property reads the state of a particular variable, and changes the widget appearance accordingly. For example, if you flip the switch from On to Off, that change is not actually a state of the widget, but you can assign the variable, val, to record this state, and then the appearance of the widget with look like the state you want, since val gets sent over to the value property, and the widget is redrawn.