Focus on It is a Dart library that allows you to get notified when a Flutter widget is focused or unfocused and react to it.

It is a continuation of the Focus Detector project, which is no longer maintained.

About

Similar to the onResume()/onPause() methods on Android and the viewDidAppear()/viewDidDisappear() methods on iOS, Focus on It lets you know when a Flutter widget is focused or unfocused and gives you the opportunity to do something about it. You can use callbacks to get more control over your app and manage the events you want, such as:

• Pause a video when the user is not looking at it.
• Stop a camera preview when the user is not looking at it and start it again when the user looks at it.
• Turn off a resource-intensive feature when the user is not looking at it and turn it on again when the user looks at it.
• Sync data with an API when the user opens a screen.
• And much more!

Installation

To install Focus on It, you can use either of the following methods:

Method 1: flutter pub add

Use the flutter pub add command to install Focus on It:

flutter pub add focus_on_it

Method 2: pubspec.yaml

Alternatively, you can add the following line to your pubspec.yaml file:

dependencies:
  focus_on_it: ^VERSION

Replace VERSION with the latest version of Focus on It. You can find the latest version on the pub.dev page.

Then, run flutter pub get to install the library.

Import the library into your code by adding the following line at the top of your file:

import 'package:focus_on_it/focus_on_it.dart';

Events

Focus on It offers 6 events to help you manage your app:

• onFocus: Equivalent to onResume() on Android and viewDidAppear() on iOS. Triggered when the Flutter widget is focused after a route transition or when the widget is resumed from a paused state.
• onUnfocus: Equivalent to onPause() on Android and viewDidDisappear() on iOS. Triggered when the Flutter widget is unfocused after a route transition or when the widget is paused from a focused state.
• onForegroundGained: Triggered when the app is resumed from a paused state.
• onForegroundLost: Triggered when the app is paused from a resumed state.
• onVisibilityGained: Triggered when the Flutter widget is visible after a route transition.
• onVisibilityLost: Triggered when the Flutter widget is no longer visible after a route transition.

Usage

@override
Widget build(BuildContext context) =>
    FocusOnIt(
      onFocus: () {
        /// Equivalent to `onResume()` on Android and `viewDidAppear()` on iOS. 
        /// Triggered when the widget is focused after route transition or the widget resumed from a paused state.
        logger.i('Focus Gained.');
      },
      onUnfocus: () {
        /// Equivalent to `onPause()` on Android and `viewDidDisappear()` on iOS. 
        /// Triggered when the widget is unfocused after route transition or the widget paused from a focused state.
        logger.i('Focus Lost.');
      },
      onForegroundGained: () {
        /// Triggered when the app is resumed from a paused state.
        logger.i('Foreground Gained.');
      },
      onForegroundLost: () {
        /// Triggered when the app is paused from a resumed state.
        logger.i('Foreground Lost.');
      },
      onVisibilityGained: () {
        /// Triggered when the widget is visible after route transition.
        logger.i('Visibility Gained.');
      },
      onVisibilityLost: () {
        /// Triggered when the widget is no longer visible after route transition.
        logger.i('Visibility Lost.');
      },
      child: const Placeholder(),
    );

Example

To see an example of how to use Focus on It, check out the following file in this repository:

• Focus On It Example

Contributing

We welcome contributions to the Focus on It project! If you would like to contribute, please feel free to reach out to the current maintainers for more information.

Issues

If you encounter any issues while using Focus on It, please open a new issue in the issue tracker. Please include as much information as possible, such as the version of Focus on It you are using and steps to reproduce the issue.

License

Focus on It is licensed under the MIT license. See LICENSE for more information.