Flutter ListView lazy loading

Lazy loading in Flutter is a technique used to load only the necessary items into a ListView as the user scrolls, rather than loading all items at once. This can improve the performance of your app, especially when loading large amounts of data.

Here’s an example of how to implement lazy loading in a ListView in Flutter:

1. Create a ListView.builder widget instead of a regular ListView. The ListView.builder widget is a more efficient way to create a list, as it only creates the items that are visible on the screen.

ListView.builder(
  itemCount: _items.length,
  itemBuilder: (BuildContext context, int index) {
    return ListTile(
      title: Text(_items[index]),
    );
  },
),

Load more items into the list as the user scrolls. This can be done by using the scrollController of the ListView and checking if the user has scrolled to the end of the list.

ScrollController _scrollController = ScrollController();

...

ListView.builder(
  controller: _scrollController,
  itemCount: _items.length,
  itemBuilder: (BuildContext context, int index) {
    // Load more items if the user has scrolled to the end of the list
    if (index == _items.length - 1) {
      _loadMoreItems();
    }

    return ListTile(
      title: Text(_items[index]),
    );
  },
),

Implement the _loadMoreItems method to load more items into the list. This can be done by making an API call, or by reading from a database, for example.

void _loadMoreItems() {
  setState(() {
    _items.addAll(...);
  });
}

In this example, the _loadMoreItems method adds more items to the list, and the setState method is called to rebuild the ListView with the new data.

Note: This is just a basic implementation of lazy loading in a ListView, and you may need to make modifications to this code to fit your specific use case.