- FocusNode currentNode
Focuses the previous widget in the focus scope that contains the given
This should determine what the previous node to receive focus should be by inspecting the node tree, and then calling FocusNode.requestFocus on the node that has been selected.
Returns true if it successfully found a node and requested focus.
currentNode argument must not be null.
bool previous(FocusNode currentNode) => _moveFocus(currentNode, forward: false);