expandable_tree_menu

Builds a Tree of Sub-menus that can be expanded/collapsed, where each node can recursively contain another tree, using a recursive list of "Nodes".

Each Node has a value payload that will be passed to the onSelect handler.

Nodes are rendered using a nodeBuilder which will use the value of the node.

Options available:

• initiallyExpanded: true // start with all nodes expanded (default is collapsed)
• twistyPosition: TwistyPosition.before (default is TwistyPosition.after)
• openTwistyColor: Color // Used when children are expanded (default based on theme)
• closedTwistyColor: Color // Used when children are collapsed (default based on theme)
• openTwisty: Widget // Widget used when children are expanded (default Icons.expand_less)
• closedTwisty: Widget // Widget used when children are collapsed (default: Icons.expand_more)
• childIndent: double // Left offset used for expanded children under the node (default: 28)
• submenuDecoration: BoxDecoration? // Border and background of submenu with children
• childrenDecoration: BoxDecoration // Border and background of children under submenu
• childrenMargin: EdgeInsets? // Margin around children under Submenu
• submenuMargin: EdgeInsets // Margin around submenu with children
• submenuClosedColor: Color // Used for submenu when collapsed
• submenuOpenColor: Color // Used for submenu when expanded ;

Basic Usage

ExpandableTree(
  nodes: [
    TreeNode('Category A',
      subNodes: [
        TreeNode('CatA first item'),
        TreeNode('CatA second item'),
      ],
    ),
    TreeNode('Category B',
      subNodes: [
        TreeNode('Cat B first item'),
        TreeNode('Cat B sub-category 1',
          subNodes: [
            TreeNode('Cat B1 first item'),
            TreeNode('Cat B1 second item'),
            TreeNode('Cat B1 third item'),
            TreeNode('Cat B1 final item'),
          ],
        ),
      ],
    ),
  ],
  nodeBuilder: (context, nodeValue) => Card(
    child: Text(nodeValue.toString()),
  ),
  onSelect: (node) => _nodeSelected(context, node),
)