flutter_post_frame 0.0.1

A lightweight Flutter package that provides utilities to execute callbacks after the first frame is rendered. Perfect for getting widget sizes or performing post-build operations.

flutter_post_frame

A lightweight Flutter package that provides utilities to execute callbacks after the first frame is rendered. Perfect for getting widget sizes or performing post-build operations.

Features

• FlutterPostFrameMixin: A mixin for StatefulWidget states that calls onAfterBuildFrame() after the first frame is rendered.
• PostFrameBuilder: A widget wrapper that provides a callback with the BuildContext and rendered widget's Size after the first frame.

Getting started

Add the package to your pubspec.yaml:

dependencies:
  flutter_post_frame: ^0.0.1

Then run:

flutter pub get

Usage

Using FlutterPostFrameMixin

Add the mixin to your State class to execute code after the first frame:

import 'package:flutter_post_frame/flutter_post_frame.dart';

class MyWidgetState extends State<MyWidget> with FlutterPostFrameMixin<MyWidget> {
  @override
  FutureOr<void> onAfterBuildFrame(BuildContext context) {
    // This runs after the first frame is rendered
    print('Widget has been rendered!');
  }

  @override
  Widget build(BuildContext context) {
    return Container();
  }
}

Using PostFrameBuilder

Wrap your widget with PostFrameBuilder to get the widget's size after rendering:

import 'package:flutter_post_frame/post_frame_builder.dart';

PostFrameBuilder(
  onAfterBuildFrame: (context, size) {
    print('Widget size: $size');
  },
  child: Container(
    width: 200,
    height: 100,
    color: Colors.blue,
  ),
)

initState-like behavior in StatelessWidget

Use PostFrameBuilder to execute one-time initialization logic in a StatelessWidget, similar to initState in StatefulWidget:

import 'package:flutter_post_frame/post_frame_builder.dart';

class MyStatelessWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return PostFrameBuilder(
      onAfterBuildFrame: (context, size) {
        // This runs once after the first frame - like initState!
        // Perfect for:
        // - Showing a dialog or snackbar
        // - Triggering navigation
        // - Fetching data based on widget size
        // - Starting animations
        print('Widget initialized with size: $size');
      },
      child: YourContentWidget(),
    );
  }
}

This is especially useful when you want to keep your widget stateless but still need to perform post-build operations.

Supported Platforms

Android	iOS	Linux	macOS	Web	Windows
✅	✅	✅	✅	✅	✅

Additional information

This package uses WidgetsBinding.instance.endOfFrame to ensure callbacks are executed after the widget tree has been fully rendered. This is particularly useful when you need to:

• Get the actual rendered size of a widget
• Perform navigation or show dialogs after the initial build
• Execute animations or scroll operations that depend on layout completion

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

• Repository
• Issue Tracker

License

This project is licensed under the MIT License - see the LICENSE file for details.