expandAll method
void
expandAll()
展开所有 node
Implementation
void expandAll() {
assert(_isInitialized);
List<EasyTreeNode<E>> result = flatTree(_initialNodes);
for (EasyTreeNode<E> item in result) {
if (!item.expanded && !item.isLeaf) this.expand(item);
}
toggleNodeExpanded(_initialNodes, true);
}