legacy_gantt_chart 0.2.0

A flexible and performant Gantt chart widget for Flutter. Supports interactive drag-and-drop, resizing, dynamic data loading, and extensive theming.

Legacy Gantt Chart

A flexible and performant Gantt chart widget for Flutter. Supports interactive drag-and-drop, resizing, dynamic data loading, and extensive theming.

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Features

• Performant Rendering: Uses CustomPainter for efficient rendering of a large number of tasks and grid lines.
• Dynamic Data Loading: Fetch tasks asynchronously for the visible date range using a LegacyGanttController.
• Interactive Tasks: Built-in support for dragging, dropping, and resizing tasks.
• Task Stacking: Automatically stacks overlapping tasks within the same row.
• Customization:
  • Extensive theming support via LegacyGanttTheme.
  • Use custom builders (taskBarBuilder, taskContentBuilder) to render completely unique task widgets.
• Timeline Navigation: Includes a LegacyGanttTimelineScrubber widget for an intuitive overview and navigation of the entire timeline.
• Special Task Types: Support for summary bars, background highlights (e.g., for holidays), and conflict indicators.

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Installation

Add this to your package's pubspec.yaml file:

dependencies:
  legacy_gantt_chart: ^0.1.0 # Replace with the latest version

Then, you can install the package using the command-line:

flutter pub get

Now, import it in your Dart code:

import 'package:legacy_gantt_chart/legacy_gantt_chart.dart';

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Quick Start

Here is a minimal example of how to create a static Gantt chart.

import 'package:flutter/material.dart';
import 'package:legacy_gantt_chart/legacy_gantt_chart.dart';

class MinimalGanttChart extends StatelessWidget {
  const MinimalGanttChart({super.key});

  @override
  Widget build(BuildContext context) {
    // 1. Define your rows
    final List<LegacyGanttRow> rows = [
      LegacyGanttRow(id: 'dev', name: 'Development'),
      LegacyGanttRow(id: 'design', name: 'Design'),
    ];

    // 2. Define your tasks and assign them to rows
    final List<LegacyGanttTask> tasks = [
      LegacyGanttTask(
        id: 'task1',
        rowId: 'dev',
        name: 'Implement Feature A',
        startDate: DateTime.now().subtract(const Duration(days: 5)),
        endDate: DateTime.now().add(const Duration(days: 5)),
      ),
      LegacyGanttTask(
        id: 'task2',
        rowId: 'design',
        name: 'Create Mockups',
        startDate: DateTime.now().subtract(const Duration(days: 8)),
        endDate: DateTime.now(),
      ),
    ];

    // 3. Create the widget
    return LegacyGanttChartWidget(
      rows: rows,
      tasks: tasks,
    );
  }
}

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Running the Example

To see a full-featured demo of the legacy_gantt_chart in action, you can run the example application included in the repository.

1. Navigate to the example directory:

   cd example
   

2. Install dependencies:

   flutter pub get
   

3. Run the app:

   flutter run
   

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Advanced Usage

Dynamic Data Loading with LegacyGanttController

For real-world applications, you'll often need to load data from a server based on the visible date range. The LegacyGanttController is designed for this purpose.

class DynamicGanttChartPage extends StatefulWidget {
  @override
  _DynamicGanttChartPageState createState() => _DynamicGanttChartPageState();
}

class _DynamicGanttChartPageState extends State<DynamicGanttChartPage> {
  late final LegacyGanttController _controller;
  final List<LegacyGanttRow> _rows = [LegacyGanttRow(id: 'row1')];

  @override
  void initState() {
    super.initState();
    _controller = LegacyGanttController(
      initialVisibleStartDate: DateTime.now().subtract(const Duration(days: 15)),
      initialVisibleEndDate: DateTime.now().add(const Duration(days: 15)),
      tasksAsync: _fetchTasks, // Your data fetching function
    );
  }

  Future<List<LegacyGanttTask>> _fetchTasks(DateTime start, DateTime end) async {
    // In a real app, you would make a network request here.
    await Future.delayed(const Duration(seconds: 1));
    return [ /* ... your fetched tasks ... */ ];
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Dynamic Gantt Chart')),
      body: LegacyGanttChartWidget(
        controller: _controller,
        visibleRows: _rows,
        rowMaxStackDepth: const {'row1': 1},
      ),
    );
  }
}

Timeline Navigation with LegacyGanttTimelineScrubber

Combine the LegacyGanttController with the LegacyGanttTimelineScrubber to provide users with a powerful way to navigate the chart's timeline.

Column(
  children: [
    Expanded(
      child: LegacyGanttChartWidget(
        controller: _controller,
        // ... other properties
      ),
    ),
    LegacyGanttTimelineScrubber(
      totalStartDate: DateTime(2023, 1, 1),
      totalEndDate: DateTime(2024, 12, 31),
      visibleStartDate: _controller.visibleStartDate,
      visibleEndDate: _controller.visibleEndDate,
      tasks: _controller.tasks,
      onWindowChanged: (newStart, newEnd) {
        _controller.setVisibleRange(newStart, newEnd);
      },
    ),
  ],
)

Interactive Tasks (Drag & Drop, Resize)

Enable interactivity and listen for updates using the onTaskUpdate callback.

LegacyGanttChartWidget(
  // ... other properties
  enableDragAndDrop: true,
  enableResize: true,
  onTaskUpdate: (task, newStart, newEnd) {
    // Here you would update your state and likely call an API
    // to persist the changes.
  },
)

Custom Task Appearance

Use taskContentBuilder to replace the content inside the task bar, or taskBarBuilder to replace the entire task bar widget for full control.

LegacyGanttChartWidget(
  // ... other properties
  taskContentBuilder: (task) {
    return Text(task.name ?? '', style: const TextStyle(color: Colors.white));
  },
)

Theming

Customize colors, text styles, and more by providing a LegacyGanttTheme.

LegacyGanttChartWidget(
  // ... other properties
  theme: LegacyGanttTheme.fromTheme(Theme.of(context)).copyWith(
    barColorPrimary: Colors.green,
    gridColor: Colors.grey.shade800,
  ),
)

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Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

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License

This project is licensed under the MIT License.