Tree View disordered if id greater than 10

[minganp]

Tree View disordered if id greater than 10.
I sugest you change like this:
_buildTreeView() {
var k = widget.data
.where((data) {
return data.getParentId() == widget.config.rootId;
})
.map((data) {
return data.getId();
})
.toSet()
.toList()
..sort((i, j) => int.parse(i).compareTo(int.parse(j)));

var widgets = List<ParentWidget>();
k.forEach((f) {
  ParentWidget p = buildWidget(f, null);
  if (p != null) widgets.add(p);
});
setState(() {
  treeView = widgets;
});

}