Infinite List in Flutter Application

Question

I am migrating my application from android to flutter and till now I have used ListView in a flutter. my question is, is there any specialized technique to handle a large amount of data in the flutter? for reference, you can look at android RecyclerView. it handles in-memory views and recycles its runtime. so how to achieve functionality like RecyclerView in Flutter? or it's not necessary for the flutter?

Answer 1

The easiest way is to use a ListView.builder without specifying the itemCount parameter.

Here is the simplest example:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text("Infinite List"),
      ),
      body: ListView.builder(
        itemBuilder: (context, index) {
          return Text("$index");
        },
      ),
    );
  }
}

Later, you can enhance this by fetching real data. You could show a 'CircularProgressIndicator' in the last item of the list while waiting for the new data.

  body: ListView.builder(
    itemBuilder: (context, index) {
      if (index < data.length) {
        // Show your info
        Text("$index");
      } else {
        getMoreData();
        return Center(child: CircularProgressIndicator());
      }
    },
    itemCount: data.length + 1,
  ),

You can see that we trick the list by adding an index, and calling for more data when displaying that final index.

getMoreData() would include a call to setState() to force a rebuild and to take into account the new data.