visibility_aware_state 0.9.1

A state for StatefulWidgets that is aware of its visiblity.

visibility_aware_state

A state for StatefulWidgets that is aware of its visiblity.

That can be useful for screen view tracking or e.g. if your app shows files it can be used to automatically refresh the files when the app is reopened again.

Features

Notice when:

• the app is put in the background or brought out of the background
• the widget initially becomes visible
• the widget becomes invisble (a new page is pushed)
• the widget is removed from stack
• the widget becomes visible again (e.g. back button on Android is pressed)

Getting started

In the pubspec.yaml of your flutter project, add the following dependency:

dependencies:
  ...
  visibility_aware_state: <latest_version>

In your library add the following import:

import 'package:visibility_aware_state/visibility_aware_state.dart';

For help getting started with Flutter, view the online documentation.

Example

class Example extends StatefulWidget {
  @override
  _ExampleState createState() => _ExampleState();
}

class _ExampleState extends VisibilityAwareState<Example> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Example app'),
      ),
      body: Center(
        child: Text('Welcome to visibility_aware_state example app.'),
      ),
    );
  }

  @override
  void onVisibilityChanged(WidgetVisibility visibility) {
    // TODO: Use visibility
    super.onVisibilityChanged(visibility);
  }
}

You can find more examples in the Example project.

Here is a specific example where the visibilty is used for screen view tracking:

import 'package:flutter/widgets.dart';
import 'package:visibility_aware_state/visibility_aware_state.dart';

import 'tracker.dart';

abstract class ScreenState<T extends StatefulWidget>
    extends VisibilityAwareState<T> with Screen {

  @override
  void onVisibilityChanged(WidgetVisibility visibility) {
    if (visibility == WidgetVisibility.VISIBLE) {
      Tracker().trackScreen(this);
    }
    super.onVisibilityChanged(visibility);
  }

  @override
  String screenName() {
    return runtimeType.toString();
  }

}

mixin Screen {

  String screenName();

}

Contributions

Feel free to contribute to this project.

If you find a bug or want a feature, but don't know how to fix/implement it, please fill an issue. If you fixed a bug or implemented a new feature, please send a pull request.