Flutter Tree View

Kapil Sharma

27 April 2023

This article focuses on looking at TreeView examples that are simple to reuse. We have an excellent tool for representing hierarchical data in a widget like a Flutter Tree View.

A few points that make this widget helpful to create a flutter app:

highly adaptable. The UI is designed by yourself, and it solely manages the data’s tree structure.
The reuse mechanism of the ListView widget makes performance efficient.
Growing child levels and child nodes indefinitely.
data import from a map
features convenient ways to create, update, and remove nodes.

You may also check our Flutter app development page

Let’s start flutter tree view implementation with a demo mobikul flutter app in a few easy steps.

1) Project Setup:

Create a new flutter project and add latest flutter_treeview version under dependencies in pubspec.yaml file of your project as following example and run flutter pub get command to install the package in your project.

dependencies:

  flutter_treeview: ^1.0.7+1

dependencies:

flutter_treeview: ^1.0.7+1

2) Import package:
Import flutter tree view using following line in the class you need to implement this functionality.

import 'package:flutter_treeview/flutter_treeview.dart';

1	import 'package:flutter_treeview/flutter_treeview.dart';

3) Creates Nodes:
We need to create a list of node with its children as per our requirement as following example.

_nodes = &#91;
      Node(
        label: 'documents',
        key: 'docs',
        expanded: docsOpen,
        icon: docsOpen ? Icons.folder_open : Icons.folder,
        children: &#91;
          Node(
            label: 'personal',
            key: 'd3',
            icon: Icons.input,
            iconColor: Colors.red,
            children: &#91;
              Node(
                label: 'Poems.docx',
                key: 'pd1',
                icon: Icons.insert_drive_file,
              ),
              Node(
                label: 'Job Hunt',
                key: 'jh1',
                icon: Icons.input,
                children: &#91;
                  Node(
                    label: 'Resume.docx',
                    key: 'jh1a',
                    icon: Icons.insert_drive_file,
                  ),
                  Node(
                    label: 'Cover Letter.docx',
                    key: 'jh1b',
                    icon: Icons.insert_drive_file,
                  ),
                ],
              ),
            ],
          ),
          Node(
            label: 'Inspection.docx',
            key: 'd1',
//          icon: Icons.insert_drive_file),
          ),
          Node(label: 'Invoice.docx', key: 'd2', icon: Icons.insert_drive_file),
        ],
      ),
      Node(
          label: 'MeetingReport.xls',
          key: 'mrxls',
          icon: Icons.insert_drive_file),
   
    ];

_nodes = [

Node(

label: 'documents',

key: 'docs',

expanded: docsOpen,

icon: docsOpen ? Icons.folder_open : Icons.folder,

children: [

Node(

label: 'personal',

key: 'd3',

icon: Icons.input,

iconColor: Colors.red,

children: [

Node(

label: 'Poems.docx',

key: 'pd1',

icon: Icons.insert_drive_file,

Node(

label: 'Job Hunt',

key: 'jh1',

icon: Icons.input,

children: [

Node(

label: 'Resume.docx',

key: 'jh1a',

icon: Icons.insert_drive_file,

Node(

label: 'Cover Letter.docx',

key: 'jh1b',

icon: Icons.insert_drive_file,

Node(

label: 'Inspection.docx',

key: 'd1',

// icon: Icons.insert_drive_file),

Node(label: 'Invoice.docx', key: 'd2', icon: Icons.insert_drive_file),

Node(

label: 'MeetingReport.xls',

key: 'mrxls',

icon: Icons.insert_drive_file),

];

4. Create a Map:
We need list of map data as per our requirement as following example.

const List&lt;Map&lt;String, dynamic&gt;&gt; US_STATES = &#91;
  {
    "label": "A",
    "children": &#91;
      {"label": "Alabama", "key": "AL"},
      {"label": "Alaska", "key": "AK"},
      {"label": "American Samoa", "key": "AS"},
      {"label": "Arizona", "key": "AZ"},
      {"label": "Arkansas", "key": "AR"}
    ]
  },
  {
    "label": "C",
    "children": &#91;
      {"label": "California", "key": "CA"},
      {"label": "Colorado", "key": "CO"},
      {"label": "Connecticut", "key": "CT"},
    ]
  },

];

String US_STATES_JSON = jsonEncode(US_STATES);

const List<Map<String, dynamic>> US_STATES = [

{

"label": "A",

"children": [

{"label": "Alabama", "key": "AL"},

{"label": "Alaska", "key": "AK"},

{"label": "American Samoa", "key": "AS"},

{"label": "Arizona", "key": "AZ"},

{"label": "Arkansas", "key": "AR"}

]

{

"label": "C",

"children": [

{"label": "California", "key": "CA"},

{"label": "Colorado", "key": "CO"},

{"label": "Connecticut", "key": "CT"},

]

];

String US_STATES_JSON = jsonEncode(US_STATES);

5. Complete Implementation:
Here we have complete implementation of flutter tree view.

import 'package:example/states.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_treeview/flutter_treeview.dart';

void main() =&gt; runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'TreeView Example',
      home: MyHomePage(title: 'TreeView Example'),
      theme: ThemeData().copyWith(
        accentColor: Colors.deepPurple,
        hoverColor: Colors.red.shade100,
        colorScheme: ThemeData().colorScheme.copyWith(primary: Colors.red),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() =&gt; _MyHomePageState();
}

class _MyHomePageState extends State&lt;MyHomePage&gt; {
  String _selectedNode;
  List&lt;Node&gt; _nodes;
  TreeViewController _treeViewController;
  bool docsOpen = true;
  bool deepExpanded = true;
  final Map&lt;ExpanderPosition, Widget&gt; expansionPositionOptions = const {
    ExpanderPosition.start: Text('Start'),
    ExpanderPosition.end: Text('End'),
  };
  final Map&lt;ExpanderType, Widget&gt; expansionTypeOptions = {
    ExpanderType.none: Container(),
    ExpanderType.caret: Icon(
      Icons.arrow_drop_down,
      size: 28,
    ),
    ExpanderType.arrow: Icon(Icons.arrow_downward),
    ExpanderType.chevron: Icon(Icons.expand_more),
    ExpanderType.plusMinus: Icon(Icons.add),
  };
  final Map&lt;ExpanderModifier, Widget&gt; expansionModifierOptions = const {
    ExpanderModifier.none: ModContainer(ExpanderModifier.none),
    ExpanderModifier.circleFilled: ModContainer(ExpanderModifier.circleFilled),
    ExpanderModifier.circleOutlined:
        ModContainer(ExpanderModifier.circleOutlined),
    ExpanderModifier.squareFilled: ModContainer(ExpanderModifier.squareFilled),
    ExpanderModifier.squareOutlined:
        ModContainer(ExpanderModifier.squareOutlined),
  };
  ExpanderPosition _expanderPosition = ExpanderPosition.start;
  ExpanderType _expanderType = ExpanderType.caret;
  ExpanderModifier _expanderModifier = ExpanderModifier.none;
  bool _allowParentSelect = false;
  bool _supportParentDoubleTap = false;

  @override
  void initState() {
    _nodes = &#91;
      Node(
        label: 'documents',
        key: 'docs',
        expanded: docsOpen,
        icon: docsOpen ? Icons.folder_open : Icons.folder,
        children: &#91;
          Node(
            label: 'personal',
            key: 'd3',
            icon: Icons.input,
            iconColor: Colors.red,
            children: &#91;
              Node(
                label: 'Poems.docx',
                key: 'pd1',
                icon: Icons.insert_drive_file,
              ),
              Node(
                label: 'Job Hunt',
                key: 'jh1',
                icon: Icons.input,
                children: &#91;
                  Node(
                    label: 'Resume.docx',
                    key: 'jh1a',
                    icon: Icons.insert_drive_file,
                  ),
                  Node(
                    label: 'Cover Letter.docx',
                    key: 'jh1b',
                    icon: Icons.insert_drive_file,
                  ),
                ],
              ),
            ],
          ),
          Node(
            label: 'Inspection.docx',
            key: 'd1',
//          icon: Icons.insert_drive_file),
          ),
          Node(label: 'Invoice.docx', key: 'd2', icon: Icons.insert_drive_file),
        ],
      ),
      Node(
          label: 'MeetingReport.xls',
          key: 'mrxls',
          icon: Icons.insert_drive_file),
      Node(
          label: 'MeetingReport.pdf',
          key: 'mrpdf',
          iconColor: Colors.green.shade300,
          selectedIconColor: Colors.white,
          icon: Icons.insert_drive_file),
      Node(label: 'Demo.zip', key: 'demo', icon: Icons.archive),
      Node(
        label: 'empty folder',
        key: 'empty',
        parent: true,
      ),
    ];
    _treeViewController = TreeViewController(
      children: _nodes,
      selectedKey: _selectedNode,
    );

    super.initState();
  }

  ListTile _makeExpanderPosition() {
    return ListTile(
      title: Text('Expander Position'),
      dense: true,
      trailing: CupertinoSlidingSegmentedControl(
        children: expansionPositionOptions,
        groupValue: _expanderPosition,
        onValueChanged: (ExpanderPosition newValue) {
          setState(() {
            _expanderPosition = newValue;
          });
        },
      ),
    );
  }

  SwitchListTile _makeAllowParentSelect() {
    return SwitchListTile.adaptive(
      title: Text('Allow Parent Select'),
      dense: true,
      value: _allowParentSelect,
      onChanged: (v) {
        setState(() {
          _allowParentSelect = v;
        });
      },
    );
  }

  SwitchListTile _makeSupportParentDoubleTap() {
    return SwitchListTile.adaptive(
      title: Text('Support Parent Double Tap'),
      dense: true,
      value: _supportParentDoubleTap,
      onChanged: (v) {
        setState(() {
          _supportParentDoubleTap = v;
        });
      },
    );
  }

  ListTile _makeExpanderType() {
    return ListTile(
      title: Text('Expander Style'),
      dense: true,
      trailing: CupertinoSlidingSegmentedControl(
        children: expansionTypeOptions,
        groupValue: _expanderType,
        onValueChanged: (ExpanderType newValue) {
          setState(() {
            _expanderType = newValue;
          });
        },
      ),
    );
  }

  ListTile _makeExpanderModifier() {
    return ListTile(
      title: Text('Expander Modifier'),
      dense: true,
      trailing: CupertinoSlidingSegmentedControl(
        children: expansionModifierOptions,
        groupValue: _expanderModifier,
        onValueChanged: (ExpanderModifier newValue) {
          setState(() {
            _expanderModifier = newValue;
          });
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    TreeViewTheme _treeViewTheme = TreeViewTheme(
      expanderTheme: ExpanderThemeData(
          type: _expanderType,
          modifier: _expanderModifier,
          position: _expanderPosition,
          // color: Colors.grey.shade800,
          size: 20,
          color: Colors.blue),
      labelStyle: TextStyle(
        fontSize: 16,
        letterSpacing: 0.3,
      ),
      parentLabelStyle: TextStyle(
        fontSize: 16,
        letterSpacing: 0.1,
        fontWeight: FontWeight.w800,
        color: Colors.blue.shade700,
      ),
      iconTheme: IconThemeData(
        size: 18,
        color: Colors.grey.shade800,
      ),
      colorScheme: Theme.of(context).colorScheme,
    );
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        elevation: 0,
      ),
      body: GestureDetector(
        onTap: () {
          FocusScope.of(context).requestFocus(FocusNode());
        },
        child: Container(
          padding: EdgeInsets.all(20),
          height: double.infinity,
          child: Column(
            children: &lt;Widget&gt;&#91;
              Container(
                height: 160,
                child: Column(
                  children: &lt;Widget&gt;&#91;
                    _makeExpanderPosition(),
                    _makeExpanderType(),
                    _makeExpanderModifier(),
//                    _makeAllowParentSelect(),
//                    _makeSupportParentDoubleTap(),
                  ],
                ),
              ),
              Expanded(
                child: Container(
                  decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(10),
                  ),
                  padding: EdgeInsets.all(10),
                  child: TreeView(
                    controller: _treeViewController,
                    allowParentSelect: _allowParentSelect,
                    supportParentDoubleTap: _supportParentDoubleTap,
                    onExpansionChanged: (key, expanded) =&gt;
                        _expandNode(key, expanded),
                    onNodeTap: (key) {
                      debugPrint('Selected: $key');
                      setState(() {
                        _selectedNode = key;
                        _treeViewController =
                            _treeViewController.copyWith(selectedKey: key);
                      });
                    },
                    theme: _treeViewTheme,
                  ),
                ),
              ),
              GestureDetector(
                onTap: () {
                  debugPrint('Close Keyboard');
                  FocusScope.of(context).unfocus();
                },
                child: Container(
                  padding: EdgeInsets.only(top: 20),
                  alignment: Alignment.center,
                  child: Text(_treeViewController.getNode(_selectedNode) == null
                      ? ''
                      : _treeViewController.getNode(_selectedNode).label),
                ),
              )
            ],
          ),
        ),
      ),
      bottomNavigationBar: SafeArea(
        top: false,
        child: ButtonBar(
          alignment: MainAxisAlignment.spaceEvenly,
          children: &lt;Widget&gt;&#91;
            CupertinoButton(
              child: Text('Node'),
              onPressed: () {
                setState(() {
                  _treeViewController = _treeViewController.copyWith(
                    children: _nodes,
                  );
                });
              },
            ),
            CupertinoButton(
              child: Text('JSON'),
              onPressed: () {
                setState(() {
                  _treeViewController =
                      _treeViewController.loadJSON(json: US_STATES_JSON);
                });
              },
            ),
//            CupertinoButton(
//              child: Text('Toggle'),
//              onPressed: _treeViewController.selectedNode != null &amp;&amp;
//                      _treeViewController.selectedNode.isParent
//                  ? () {
//                      setState(() {
//                        _treeViewController = _treeViewController
//                            .withToggleNode(_treeViewController.selectedKey);
//                      });
//                    }
//                  : null,
//            ),
            CupertinoButton(
              child: Text('Deep'),
              onPressed: () {
                String deepKey = 'jh1b';
                setState(() {
                  if (deepExpanded == false) {
                    List&lt;Node&gt; newdata =
                        _treeViewController.expandToNode(deepKey);
                    _treeViewController =
                        _treeViewController.copyWith(children: newdata);
                    deepExpanded = true;
                  } else {
                    _treeViewController =
                        _treeViewController.withCollapseToNode(deepKey);
                    deepExpanded = false;
                  }
                });
              },
            ),
            CupertinoButton(
              child: Text('Edit'),
              onPressed: () {
                TextEditingController editingController = TextEditingController(
                    text: _treeViewController.selectedNode.label);
                showCupertinoDialog(
                    context: context,
                    builder: (context) {
                      return CupertinoAlertDialog(
                        title: Text('Edit Label'),
                        content: Container(
                          height: 80,
                          alignment: Alignment.center,
                          padding: EdgeInsets.all(10),
                          child: CupertinoTextField(
                            controller: editingController,
                            autofocus: true,
                          ),
                        ),
                        actions: &lt;Widget&gt;&#91;
                          CupertinoDialogAction(
                            child: Text('Cancel'),
                            isDestructiveAction: true,
                            onPressed: () =&gt; Navigator.of(context).pop(),
                          ),
                          CupertinoDialogAction(
                            child: Text('Update'),
                            isDefaultAction: true,
                            onPressed: () {
                              if (editingController.text.isNotEmpty) {
                                setState(() {
                                  Node _node = _treeViewController.selectedNode;
                                  _treeViewController =
                                      _treeViewController.withUpdateNode(
                                          _treeViewController.selectedKey,
                                          _node.copyWith(
                                              label: editingController.text));
                                });
                                debugPrint(editingController.text);
                              }
                              Navigator.of(context).pop();
                            },
                          ),
                        ],
                      );
                    });
              },
            ),
          ],
        ),
      ),
    );
  }

  _expandNode(String key, bool expanded) {
    String msg = '${expanded ? "Expanded" : "Collapsed"}: $key';
    debugPrint(msg);
    Node node = _treeViewController.getNode(key);
    if (node != null) {
      List&lt;Node&gt; updated;
      if (key == 'docs') {
        updated = _treeViewController.updateNode(
            key,
            node.copyWith(
              expanded: expanded,
              icon: expanded ? Icons.folder_open : Icons.folder,
            ));
      } else {
        updated = _treeViewController.updateNode(
            key, node.copyWith(expanded: expanded));
      }
      setState(() {
        if (key == 'docs') docsOpen = expanded;
        _treeViewController = _treeViewController.copyWith(children: updated);
      });
    }
  }
}

class ModContainer extends StatelessWidget {
  final ExpanderModifier modifier;

  const ModContainer(this.modifier, {Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    double _borderWidth = 0;
    BoxShape _shapeBorder = BoxShape.rectangle;
    Color _backColor = Colors.transparent;
    Color _backAltColor = Colors.grey.shade700;
    switch (modifier) {
      case ExpanderModifier.none:
        break;
      case ExpanderModifier.circleFilled:
        _shapeBorder = BoxShape.circle;
        _backColor = _backAltColor;
        break;
      case ExpanderModifier.circleOutlined:
        _borderWidth = 1;
        _shapeBorder = BoxShape.circle;
        break;
      case ExpanderModifier.squareFilled:
        _backColor = _backAltColor;
        break;
      case ExpanderModifier.squareOutlined:
        _borderWidth = 1;
        break;
    }
    return Container(
      decoration: BoxDecoration(
        shape: _shapeBorder,
        border: _borderWidth == 0
            ? null
            : Border.all(
                width: _borderWidth,
                color: _backAltColor,
              ),
        color: _backColor,
      ),
      width: 15,
      height: 15,
    );
  }
}

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import 'package:example/states.dart';

import 'package:flutter/cupertino.dart';

import 'package:flutter/material.dart';

import 'package:flutter_treeview/flutter_treeview.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {

// This widget is the root of your application.

@override

Widget build(BuildContext context) {

return MaterialApp(

title: 'TreeView Example',

home: MyHomePage(title: 'TreeView Example'),

theme: ThemeData().copyWith(

accentColor: Colors.deepPurple,

hoverColor: Colors.red.shade100,

colorScheme: ThemeData().colorScheme.copyWith(primary: Colors.red),

);

}

class MyHomePage extends StatefulWidget {

MyHomePage({Key key, this.title}) : super(key: key);

final String title;

@override

_MyHomePageState createState() => _MyHomePageState();

}

class _MyHomePageState extends State<MyHomePage> {

String _selectedNode;

List<Node> _nodes;

TreeViewController _treeViewController;

bool docsOpen = true;

bool deepExpanded = true;

final Map<ExpanderPosition, Widget> expansionPositionOptions = const {

ExpanderPosition.start: Text('Start'),

ExpanderPosition.end: Text('End'),

};

final Map<ExpanderType, Widget> expansionTypeOptions = {

ExpanderType.none: Container(),

ExpanderType.caret: Icon(

Icons.arrow_drop_down,

size: 28,

ExpanderType.arrow: Icon(Icons.arrow_downward),

ExpanderType.chevron: Icon(Icons.expand_more),

ExpanderType.plusMinus: Icon(Icons.add),

};

final Map<ExpanderModifier, Widget> expansionModifierOptions = const {

ExpanderModifier.none: ModContainer(ExpanderModifier.none),

ExpanderModifier.circleFilled: ModContainer(ExpanderModifier.circleFilled),

ExpanderModifier.circleOutlined:

ModContainer(ExpanderModifier.circleOutlined),

ExpanderModifier.squareFilled: ModContainer(ExpanderModifier.squareFilled),

ExpanderModifier.squareOutlined:

ModContainer(ExpanderModifier.squareOutlined),

};

ExpanderPosition _expanderPosition = ExpanderPosition.start;

ExpanderType _expanderType = ExpanderType.caret;

ExpanderModifier _expanderModifier = ExpanderModifier.none;

bool _allowParentSelect = false;

bool _supportParentDoubleTap = false;

@override

void initState() {

_nodes = [

Node(

label: 'documents',

key: 'docs',

expanded: docsOpen,

icon: docsOpen ? Icons.folder_open : Icons.folder,

children: [

Node(

label: 'personal',

key: 'd3',

icon: Icons.input,

iconColor: Colors.red,

children: [

Node(

label: 'Poems.docx',

key: 'pd1',

icon: Icons.insert_drive_file,

Node(

label: 'Job Hunt',

key: 'jh1',

icon: Icons.input,

children: [

Node(

label: 'Resume.docx',

key: 'jh1a',

icon: Icons.insert_drive_file,

Node(

label: 'Cover Letter.docx',

key: 'jh1b',

icon: Icons.insert_drive_file,

Node(

label: 'Inspection.docx',

key: 'd1',

// icon: Icons.insert_drive_file),

Node(label: 'Invoice.docx', key: 'd2', icon: Icons.insert_drive_file),

Node(

label: 'MeetingReport.xls',

key: 'mrxls',

icon: Icons.insert_drive_file),

Node(

label: 'MeetingReport.pdf',

key: 'mrpdf',

iconColor: Colors.green.shade300,

selectedIconColor: Colors.white,

icon: Icons.insert_drive_file),

Node(label: 'Demo.zip', key: 'demo', icon: Icons.archive),

Node(

label: 'empty folder',

key: 'empty',

parent: true,

];

_treeViewController = TreeViewController(

children: _nodes,

selectedKey: _selectedNode,

);

super.initState();

}

ListTile _makeExpanderPosition() {

return ListTile(

title: Text('Expander Position'),

dense: true,

trailing: CupertinoSlidingSegmentedControl(

children: expansionPositionOptions,

groupValue: _expanderPosition,

onValueChanged: (ExpanderPosition newValue) {

setState(() {

_expanderPosition = newValue;

});

);

}

SwitchListTile _makeAllowParentSelect() {

return SwitchListTile.adaptive(

title: Text('Allow Parent Select'),

dense: true,

value: _allowParentSelect,

onChanged: (v) {

setState(() {

_allowParentSelect = v;

});

);

}

SwitchListTile _makeSupportParentDoubleTap() {

return SwitchListTile.adaptive(

title: Text('Support Parent Double Tap'),

dense: true,

value: _supportParentDoubleTap,

onChanged: (v) {

setState(() {

_supportParentDoubleTap = v;

});

);

}

ListTile _makeExpanderType() {

return ListTile(

title: Text('Expander Style'),

dense: true,

trailing: CupertinoSlidingSegmentedControl(

children: expansionTypeOptions,

groupValue: _expanderType,

onValueChanged: (ExpanderType newValue) {

setState(() {

_expanderType = newValue;

});

);

}

ListTile _makeExpanderModifier() {

return ListTile(

title: Text('Expander Modifier'),

dense: true,

trailing: CupertinoSlidingSegmentedControl(

children: expansionModifierOptions,

groupValue: _expanderModifier,

onValueChanged: (ExpanderModifier newValue) {

setState(() {

_expanderModifier = newValue;

});

);

}

@override

Widget build(BuildContext context) {

TreeViewTheme _treeViewTheme = TreeViewTheme(

expanderTheme: ExpanderThemeData(

type: _expanderType,

modifier: _expanderModifier,

position: _expanderPosition,

// color: Colors.grey.shade800,

size: 20,

color: Colors.blue),

labelStyle: TextStyle(

fontSize: 16,

letterSpacing: 0.3,

parentLabelStyle: TextStyle(

fontSize: 16,

letterSpacing: 0.1,

fontWeight: FontWeight.w800,

color: Colors.blue.shade700,

iconTheme: IconThemeData(

size: 18,

color: Colors.grey.shade800,

colorScheme: Theme.of(context).colorScheme,

);

return Scaffold(

appBar: AppBar(

title: Text(widget.title),

elevation: 0,

body: GestureDetector(

onTap: () {

FocusScope.of(context).requestFocus(FocusNode());

child: Container(

padding: EdgeInsets.all(20),

height: double.infinity,

child: Column(

children: <Widget>[

Container(

height: 160,

child: Column(

children: <Widget>[

_makeExpanderPosition(),

_makeExpanderType(),

_makeExpanderModifier(),

// _makeAllowParentSelect(),

// _makeSupportParentDoubleTap(),

Expanded(

child: Container(

decoration: BoxDecoration(

borderRadius: BorderRadius.circular(10),

padding: EdgeInsets.all(10),

child: TreeView(

controller: _treeViewController,

allowParentSelect: _allowParentSelect,

supportParentDoubleTap: _supportParentDoubleTap,

onExpansionChanged: (key, expanded) =>

_expandNode(key, expanded),

onNodeTap: (key) {

debugPrint('Selected: $key');

setState(() {

_selectedNode = key;

_treeViewController =

_treeViewController.copyWith(selectedKey: key);

});

theme: _treeViewTheme,

GestureDetector(

onTap: () {

debugPrint('Close Keyboard');

FocusScope.of(context).unfocus();

child: Container(

padding: EdgeInsets.only(top: 20),

alignment: Alignment.center,

child: Text(_treeViewController.getNode(_selectedNode) == null

? ''

: _treeViewController.getNode(_selectedNode).label),

)

bottomNavigationBar: SafeArea(

top: false,

child: ButtonBar(

alignment: MainAxisAlignment.spaceEvenly,

children: <Widget>[

CupertinoButton(

child: Text('Node'),

onPressed: () {

setState(() {

_treeViewController = _treeViewController.copyWith(

children: _nodes,

);

});

CupertinoButton(

child: Text('JSON'),

onPressed: () {

setState(() {

_treeViewController =

_treeViewController.loadJSON(json: US_STATES_JSON);

});

// CupertinoButton(

// child: Text('Toggle'),

// onPressed: _treeViewController.selectedNode != null &&

// _treeViewController.selectedNode.isParent

// ? () {

// setState(() {

// _treeViewController = _treeViewController

// .withToggleNode(_treeViewController.selectedKey);

// });

// }

// : null,

// ),

CupertinoButton(

child: Text('Deep'),

onPressed: () {

String deepKey = 'jh1b';

setState(() {

if (deepExpanded == false) {

List<Node> newdata =

_treeViewController.expandToNode(deepKey);

_treeViewController =

_treeViewController.copyWith(children: newdata);

deepExpanded = true;

} else {

_treeViewController =

_treeViewController.withCollapseToNode(deepKey);

deepExpanded = false;

}

});

CupertinoButton(

child: Text('Edit'),

onPressed: () {

TextEditingController editingController = TextEditingController(

text: _treeViewController.selectedNode.label);

showCupertinoDialog(

context: context,

builder: (context) {

return CupertinoAlertDialog(

title: Text('Edit Label'),

content: Container(

height: 80,

alignment: Alignment.center,

padding: EdgeInsets.all(10),

child: CupertinoTextField(

controller: editingController,

autofocus: true,

actions: <Widget>[

CupertinoDialogAction(

child: Text('Cancel'),

isDestructiveAction: true,

onPressed: () => Navigator.of(context).pop(),

CupertinoDialogAction(

child: Text('Update'),

isDefaultAction: true,

onPressed: () {

if (editingController.text.isNotEmpty) {

setState(() {

Node _node = _treeViewController.selectedNode;

_treeViewController =

_treeViewController.withUpdateNode(

_treeViewController.selectedKey,

_node.copyWith(

label: editingController.text));

});

debugPrint(editingController.text);

}

Navigator.of(context).pop();

);

});

);

}

_expandNode(String key, bool expanded) {

String msg = '${expanded ? "Expanded" : "Collapsed"}: $key';

debugPrint(msg);

Node node = _treeViewController.getNode(key);

if (node != null) {

List<Node> updated;

if (key == 'docs') {

updated = _treeViewController.updateNode(

key,

node.copyWith(

expanded: expanded,

icon: expanded ? Icons.folder_open : Icons.folder,

));

} else {

updated = _treeViewController.updateNode(

key, node.copyWith(expanded: expanded));

}

setState(() {

if (key == 'docs') docsOpen = expanded;

_treeViewController = _treeViewController.copyWith(children: updated);

});

}

class ModContainer extends StatelessWidget {

final ExpanderModifier modifier;

const ModContainer(this.modifier, {Key key}) : super(key: key);

@override

Widget build(BuildContext context) {

double _borderWidth = 0;

BoxShape _shapeBorder = BoxShape.rectangle;

Color _backColor = Colors.transparent;

Color _backAltColor = Colors.grey.shade700;

switch (modifier) {

case ExpanderModifier.none:

break;

case ExpanderModifier.circleFilled:

_shapeBorder = BoxShape.circle;

_backColor = _backAltColor;

break;

case ExpanderModifier.circleOutlined:

_borderWidth = 1;

_shapeBorder = BoxShape.circle;

break;

case ExpanderModifier.squareFilled:

_backColor = _backAltColor;

break;

case ExpanderModifier.squareOutlined:

_borderWidth = 1;

break;

}

return Container(

decoration: BoxDecoration(

shape: _shapeBorder,

border: _borderWidth == 0

? null

: Border.all(

width: _borderWidth,

color: _backAltColor,

color: _backColor,

width: 15,

height: 15,

);

}

Output:

Conclusion:

In this article, we have learned about tree view structure with a simple mobikul example app using flutter_treeview: ^1.0.7+1 plugin.

Thanks for reading the blog, for more such informative articles related to latest tech trend please visit our mobikul blog site.