/// Your server data
final serverData = [
  {
    "checked": true,
    "children": [
      {
        "checked": true,
        "show": false,
        "children": [],
        "id": 11,
        "pid": 1,
        "text": "Child title 11",
      },
    ],
    "id": 1,
    "pid": 0,
    "show": false,
    "text": "Parent title 1",
  },
  {
    "checked": true,
    "show": false,
    "children": [],
    "id": 2,
    "pid": 0,
    "text": "Parent title 2",
  },
  {
    "checked": true,
    "children": [],
    "id": 3,
    "pid": 0,
    "show": false,
    "text": "Parent title 3",
  },
];

/// Map server data to tree node data
TreeNodeData mapServerDataToTreeData(Map data) {
  return TreeNodeData(
    extra: data,
    title: data['text'],
    expaned: data['show'],
    checked: data['checked'],
    children:
        List.from(data['children'].map((x) => mapServerDataToTreeData(x))),
  );
}

/// Generate tree data
List<TreeNodeData> treeData = List.generate(
  serverData.length,
  (index) => mapServerDataToTreeData(serverData[index]),
);

TreeView(data: treeData)

TreeView(
  data: treeData,
  showFilter: true,
),

TreeView(
  data: treeData,
  showCheckBox: true,
),

/// Make sure pass `append` function.

TreeView(
  data: treeData,
  showActions: true,
  showCheckBox: true,
  append: (parent) {
    print(parent.extra);
    return TreeNodeData(
      title: 'Appended',
      expaned: true,
      checked: true,
      children: [],
    );
  },
),

TreeView(
  data: treeData,
  showActions: true,
  showCheckBox: true,
  append: (parent) {
    return TreeNodeData(
      title: 'Appended',
      expaned: true,
      checked: true,
      children: [],
    );
  },
  onTap: (node) {
    print(node.extra);
  },
  onCheck: (checked, node) {
    print(checked);
    print(node.extra);
  },
  onCollapse: (node) {
    print(node.extra);
  },
  onExpand: (node) {
    print(node.extra);
  },
  onAppend: (node, parent) {
    print(node.extra);
    print(parent.extra);
  },
  onRemove: (node, parent) {
    print(node.extra);
    print(parent.extra);
  },
),

/// Create your load function, return list of TreeNodeData

Future<List<TreeNodeData>> _load(TreeNodeData parent) async {
  await Future.delayed(const Duration(seconds: 1));
  final data = [
    TreeNodeData(
      title: 'load1',
      expaned: false,
      checked: true,
      children: [],
      extra: null,
    ),
    TreeNodeData(
      title: 'load2',
      expaned: false,
      checked: false,
      children: [],
      extra: null,
    ),
  ];

  return data;
}

TreeView(
  data: treeData,
  lazy: true,
  load: _load,
  onLoad: (node) {
    print('onLoad');
    print(node.extra);
  },
),