previousFocus method
void
previousFocus()
Moves focus to the previous focusable node in the scope.
Implementation
void previousFocus() {
final chain = _focusableNodes;
if (chain.isEmpty) return;
final current = _nodes[_currentIndex];
final chainIndex = chain.indexOf(current);
final prevChainIndex = (chainIndex - 1 + chain.length) % chain.length;
final target = chain[prevChainIndex];
final targetIndex = _nodes.indexOf(target);
_setFocusAtIndex(targetIndex);
}