lazy_load_scrollview 1.1.0

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  • Changelog
  • Example
  • Installing
  • 97

Lazy load scrollview #

A wrapper for a ScrollView that will enable lazy loading

Usage #

Add lazy_load_scrollview dependency to your pubspec.yaml:

dependencies:
  lazy_load_scrollview: 1.1.0

In your Dart code, import package:lazy_load_scrollview/lazy_load_scrollview.dart Then you can wrap your ListView, GridView, RefreshIndicator etc with the LazyLoadScrollView. Make sure you add an endOfPageListener which will receive the call when the bottom of the list has been reached.

import 'package:lazy_load_scrollview/lazy_load_scrollview.dart';


@override
Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: LazyLoadScrollView(
        endOfPageListener: () => loadMore(),
        child: ListView.builder(
          itemCount: data.length,
          itemBuilder: (context, position) {
            return Text("Position $position");
          },
        ),
      ),
    );
}

Class definition #


LazyLoadScrollView(
  endOfPageListener: () => loadMore(), // The callback when reaching the end of the list
  scrollOffset: 100 // Pixels from the bottom that should trigger a callback 
  child: Widget, // A subclass of `ScrollView`
);

[1.1.0] - 28-04-2020 #

  • Updates child to accept Widget. Allowing the use for example, a RefreshIndicator

Credit: Michal Bartnicki

[1.0.1] - 8-07-2019 #

  • Updates dependencies

[1.0.0] - 29-07-2018 #

  • Release stable version

[0.0.3] - 10-04-2019 #

  • Fixes issue where the callback was called multiple times

[0.0.1] - 29-07-2018 #

  • Initial release
  • Contains basic functionality

example/lib/main.dart

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

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Lazy Load Demo',
      home: new MyHomePage(title: 'Lazy Load Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<int> data = [];
  int currentLength = 0;

  final int increment = 10;
  bool isLoading = false;

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

  Future _loadMore() async {
    setState(() {
      isLoading = true;
    });

    // Add in an artificial delay
    await new Future.delayed(const Duration(seconds: 2));
    for (var i = currentLength; i <= currentLength + increment; i++) {
      data.add(i);
    }
    setState(() {
      isLoading = false;
      currentLength = data.length;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: LazyLoadScrollView(
        isLoading: isLoading,
        onEndOfPage: () => _loadMore(),
        child: ListView.builder(
          itemCount: data.length,
          itemBuilder: (context, position) {
            return DemoItem(position);
          },
        ),
      ),
    );
  }
}

class DemoItem extends StatelessWidget {
  final int position;

  const DemoItem(
    this.position, {
    Key key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              children: <Widget>[
                Container(
                  color: Colors.grey,
                  height: 40.0,
                  width: 40.0,
                ),
                SizedBox(width: 8.0),
                Text("Item $position"),
              ],
            ),
            Text(
                "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque sed vulputate orci. Proin id scelerisque velit. Fusce at ligula ligula. Donec fringilla sapien odio, et faucibus tortor finibus sed. Aenean rutrum ipsum in sagittis auctor. Pellentesque mattis luctus consequat. Sed eget sapien ut nibh rhoncus cursus. Donec eget nisl aliquam, ornare sapien sit amet, lacinia quam."),
          ],
        ),
      ),
    );
  }
}

Use this package as a library

1. Depend on it

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


dependencies:
  lazy_load_scrollview: ^1.1.0

2. Install it

You can install packages from the command line:

with Flutter:


$ flutter pub get

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:lazy_load_scrollview/lazy_load_scrollview.dart';
  
Popularity:
Describes how popular the package is relative to other packages. [more]
94
Health:
Code health derived from static analysis. [more]
100
Maintenance:
Reflects how tidy and up-to-date the package is. [more]
100
Overall:
Weighted score of the above. [more]
97
Learn more about scoring.

We analyzed this package on Jul 2, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.8.4
  • pana: 0.13.13
  • Flutter: 1.17.5

Analysis suggestions

Package not compatible with SDK dart

because of import path [lazy_load_scrollview] that is in a package requiring null.

Dependencies

Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.0.0 <3.0.0
flutter 0.0.0
Transitive dependencies
collection 1.14.12 1.14.13
meta 1.1.8
sky_engine 0.0.99
typed_data 1.1.6 1.2.0
vector_math 2.0.8
Dev dependencies
flutter_test