drag_and_drop_lists 0.4.1

A flutter package to allow drag-and-drop reordering of two-level lists.

drag_and_drop_lists

Two-level drag and drop reorderable lists.

Features

• Reorder elements between multiple lists
• Reorder lists
• Drag and drop new elements from outside of the lists
• Vertical or horizontal layout
• Use with drag handles, long presses, or short presses
• Expandable lists
• Can be used in slivers
• Prevent individual lists/elements from being able to be dragged
• Easy to extend with custom layouts

Known Issues

There is currently (as of flutter v. 1.24.0-1.0.pre) an issue only on web where dragging an item with some descendant that includes an InkWell widget with an onTap method will throw an exception. This includes having a ListTile with an onTap method defined.

This seems to be resolved by using a GestureDetector and its onTap method instead of the InkWell.

See the following issues:

• #14
• Flutter #69774
• Flutter #67044
• Flutter #66887

Usage

To use this plugin, add drag_and_drop_lists as a dependency in your pubspec.yaml file. For example:

dependencies:
  drag_and_drop_lists: ^0.2.1

Now in your Dart code, you can use: import 'package:drag_and_drop_lists/drag_and_drop_lists.dart';

To add the lists, add a DragAndDropLists widget. Set its children to a list of DragAndDropList. Likewise, set the children of DragAndDropList to a list of DragAndDropItem. For example:

  // Outer list
  List<DragAndDropList> _contents;

  @override
  void initState() {
    super.initState();

    // Generate a list
    _contents = List.generate(10, (index) {
      return DragAndDropList(
        header: Text('Header $index'),
        children: <DragAndDropItem>[
          DragAndDropItem(
            child: Text('$index.1'),
          ),
          DragAndDropItem(
            child: Text('$index.2'),
          ),
          DragAndDropItem(
            child: Text('$index.3'),
          ),
        ],
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    // Add a DragAndDropLists. The only required parameters are children,
    // onItemReorder, and onListReorder. All other parameters are used for
    // styling the lists and changing its behaviour. See the samples in the
    // example app for many more ways to configure this.
    return DragAndDropLists(
      children: _contents,
      onItemReorder: _onItemReorder,
      onListReorder: _onListReorder,
    );
  }

  _onItemReorder(int oldItemIndex, int oldListIndex, int newItemIndex, int newListIndex) {
    setState(() {
      var movedItem = _contents[oldListIndex].children.removeAt(oldItemIndex);
      _contents[newListIndex].children.insert(newItemIndex, movedItem);
    });
  }

  _onListReorder(int oldListIndex, int newListIndex) {
    setState(() {
      var movedList = _contents.removeAt(oldListIndex);
      _contents.insert(newListIndex, movedList);
    });
  }

For further examples, see the example app or view the example code directly.