Flutter CupertinoActivityIndicator – Progress

Flutter CupertinoActivityIndicator Progress

To set a specific progress to CupertinoActivityIndicator widget in Flutter, create CupertinoActivityIndicator widget using CupertinoActivityIndicator.partiallyRevealed() constructor and pass the progress as argument.

Syntax

A CupertinoActivityIndicator with specific radius.

CupertinoActivityIndicator(
  radius: 20,
),

Example

Flutter Application with a CupertinoActivityIndicator widget.

We declared a variable activityProgress with an initial value of 0.4 (40%), and assign it to progress property of CupertinoActivityIndicator widget.

main.dart

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

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

/// main application widget
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Application';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatefulWidget(),
      ),
    );
  }
}

/// stateful widget that the main application instantiates
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

/// private State class that goes with MyStatefulWidget
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  double activityProgress = 0.4;
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        children: <Widget>[
          const SizedBox(height: 30,),
          CupertinoActivityIndicator.partiallyRevealed(
            radius: 40,
            progress: activityProgress,
          ),
        ],
      ),
    );
  }
}

Screenshot

Now, let us include a button, in our application that increases the progress by 10% for each click, and resets to 10% after 100%.

main.dart

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

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

/// main application widget
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Application';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatefulWidget(),
      ),
    );
  }
}

/// stateful widget that the main application instantiates
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

/// private State class that goes with MyStatefulWidget
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  double activityProgress = 0.4;
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        children: <Widget>[
          const SizedBox(height: 30,),
          CupertinoActivityIndicator.partiallyRevealed(
            radius: 40,
            progress: activityProgress,
          ),
          CupertinoButton(
              child: const Text('Change Progress'),
              onPressed: () {
                setState(() {
                  if (activityProgress < 0.9) {
                    activityProgress = activityProgress + 0.1;
                  } else {
                    activityProgress = 0.1;
                  }
                });
              }
          ),
        ],
      ),
    );
  }
}

Video