toggleTristate method
void
toggleTristate()
Cycles through all three states in order: checked -> unchecked -> indeterminate.
Provides complete tri-state cycling behavior. Use this instead of toggle when working with tri-state checkboxes that need to support indeterminate state.
Implementation
void toggleTristate() {
value = value == CheckboxState.checked
? CheckboxState.unchecked
: value == CheckboxState.unchecked
? CheckboxState.indeterminate
: CheckboxState.checked;
}