### Draggable GridView Example

Source: https://github.com/mindinventory/flutter_draggable_gridview/blob/main/README.md

Demonstrates how to use the DraggableGridViewBuilder widget to create a grid with drag-and-drop functionality. It includes configurations for grid layout, drag completion, feedback, and placeholder widgets.

```dart
DraggableGridViewBuilder(
        gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 2,
          childAspectRatio: MediaQuery.of(context).size.width / (MediaQuery.of(context).size.height / 3),
        ),
        children: _listOfDraggableGridItem,
        isOnlyLongPress: false,
        dragCompletion: (List<DraggableGridItem> list, int beforeIndex, int afterIndex) {
          print( 'onDragAccept: $beforeIndex -> $afterIndex');
        },
        dragFeedback: (List<DraggableGridItem> list, int index) {
          return Container(
            child: list[index].child,
            width: 200,
            height: 150,
          );
        },
        dragPlaceHolder: (List<DraggableGridItem> list, int index) {
          return PlaceHolderWidget(
            child: Container(
              color: Colors.white,
            ),
          );
        },
      );
```

--------------------------------

### DraggableGridViewBuilder Parameters

Source: https://github.com/mindinventory/flutter_draggable_gridview/blob/main/README.md

Details the required and optional parameters for the DraggableGridViewBuilder widget, explaining their purpose and usage in implementing drag-and-drop grid functionality.

```APIDOC
DraggableGridViewBuilder:
  gridDelegate: SliverGridDelegateWithFixedCrossAxisCount
    A delegate that controls the layout of the children within the GridView.
  children: List<DraggableGridItem>
    This property contains list of [DraggableGridItem] and it is use to show the widget inside the GridView.builder to provide the drag & drop functionality. Also, it contains isDraggable parameter which manages enable/disable the drag & drop functionality.
  dragCompletion: (List<DraggableGridItem> list, int beforeIndex, int afterIndex) => void
    This callback provides updated list and old and new indexes.
  isOnlyLongPress: bool (optional, default: true)
    If this property is false then it works with simple press draggable or else it works with long press.
  dragFeedback: (List<DraggableGridItem> list, int index) => Widget (optional)
    With this callback, you have to return a Widget and we will use this widget in feedback. Learn more about feedback from [Draggable](https://api.flutter.dev/flutter/widgets/Draggable-class.html#:~:text=Draggable%20class%20Null%20safety,user's%20finger%20across%20the%20screen) class.
  dragPlaceHolder: (List<DraggableGridItem> list, int index) => PlaceHolderWidget (optional)
    With this callback, you have to return a PlaceHolderWidget and we will use this widget in place holder.
  dragChildWhenDragging: (List<DraggableGridItem> list, int index) => Widget (optional)
    With this callback, you have to return a Widget and we will display this widget instead of child when drags are under way. Learn more about childWhenDragging from [Draggable](https://api.flutter.dev/flutter/widgets/Draggable-class.html#:~:text=Draggable%20class%20Null%20safety,user's%20finger%20across%20the%20screen) class.

Note: You can use all the GridView.builder properties with DraggableGridViewBuilder class.
```

--------------------------------

### Service Worker Registration for Flutter App

Source: https://github.com/mindinventory/flutter_draggable_gridview/blob/main/example/web/index.html

This JavaScript snippet demonstrates how to register a service worker for a Flutter web application. It listens for the 'flutter-first-frame' event to ensure the service worker is registered after the initial frame is rendered, which is a common practice for optimizing Flutter web performance.

```javascript
if ('serviceWorker' in navigator) {
  window.addEventListener('flutter-first-frame', function () {
    navigator.serviceWorker.register('flutter_service_worker.js');
  });
}
```

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