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LongPressDraggableCard

A customizable Flutter widget that allows users to drag a card horizontally to increase or decrease a count — perfect for cart quantities, counters, or any use case where a drag gesture adjusts a numeric value.

📽 Demo

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✨ Features

• 🔁 Horizontal drag gesture for count control
• 📈 Increase or decrease values dynamically
• ✅ Limit value using maxCount
• 🎨 Customizable feedback (fadeContainer) and UI (child)
• ⚡ Lightweight and easy to integrate

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📦 Installation

Add this to your pubspec.yaml:

dependencies:
  flutter_longpressdrag_fluctuation: ^1.0.0

Then run:

flutter pub get

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🚀 Usage

LongPressDraggableCard(
  axis: Axis.horizontal,
  count: quantity,
  maxCount: 50,
  onChanged: (value) {
    setState(() {
      quantity = value;
    });
  },
  fadeContainer: Container(
    height: 200,
    width: 500,
    margin: EdgeInsets.all(12),
    padding: EdgeInsets.all(16),
    child: Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text("", style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
        SizedBox(height: 8),
        Text("", style: TextStyle(fontSize: 14, color: Colors.grey[700])),
        SizedBox(height: 12),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text('', style: TextStyle(fontSize: 16)),
            Text('', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: Colors.green)),
          ],
        ),
      ],
    ),
  ),
  child: Container(
    height: 200,
    width: 500,
    margin: EdgeInsets.all(12),
    padding: EdgeInsets.all(16),
    child: Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text("name", style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
        SizedBox(height: 8),
        Text("description", style: TextStyle(fontSize: 14, color: Colors.grey[700])),
        SizedBox(height: 12),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text('Qty: $quantity', style: TextStyle(fontSize: 16)),
            Text('\$10', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: Colors.green)),
          ],
        ),
      ],
    ),
  ),
);

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🔧 Parameters

Property	Type	Description
axis	Axis	Direction of drag (default: Axis.horizontal)
count	int	Current value to display and update
maxCount	int	Maximum count limit
onChanged	Function(int)	Callback triggered when the count changes
fadeContainer	Widget	Transparent feedback widget shown while dragging
child	Widget	Main card widget shown to the user

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📌 How it Works

• LongPressDraggableCard listens for long press + horizontal drag.

• Internally, it uses onDragUpdate to check the offset.dx:

  • Positive → increase count
  • Negative → decrease count

• When the drag ends, onDragEnd resets the feedback offset.

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🧪 Example Use Cases

• Shopping cart item quantity control
• Rating widgets with adjustable values
• Custom counters

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💡 Tips

• Always include a transparent fadeContainer to ensure draggable feedback works.
• Use state management (like setState, Provider, etc.) to persist and respond to value changes.

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📄 License

MIT

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