rust_in_flutter 4.8.1

"Rust as your Flutter backend, Flutter as your Rust frontend"

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:rust_in_flutter/rust_in_flutter.dart';
import 'package:example_app/messages/counter_number.pb.dart' as counterNumber;
import 'package:example_app/messages/mandelbrot.pb.dart' as mandelbrot;

void main() async {
  // Wait for Rust initialization to be completed first.
  await RustInFlutter.ensureInitialized();
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'RIF Example',
      theme: ThemeData(
        useMaterial3: true,
        brightness: MediaQuery.platformBrightnessOf(context),
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});
  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() async {
    final requestMessage = counterNumber.ReadRequest(
      letter: "Hello from Dart!",
      beforeNumber: _counter,
      dummyOne: 1,
      dummyTwo: counterNumber.SampleSchema(
        sampleFieldOne: true,
        sampleFieldTwo: false,
      ),
      dummyThree: [3, 4, 5],
    );
    final rustRequest = RustRequest(
      resource: counterNumber.ID,
      operation: RustOperation.Read,
      message: requestMessage.writeToBuffer(),
    );
    // Use `requestToRust` from `rust_in_flutter.dart`
    // to send the request to Rust and get the response.
    final rustResponse = await requestToRust(rustRequest);
    if (rustResponse.successful) {
      final responseMessage = counterNumber.ReadResponse.fromBuffer(
        rustResponse.message!,
      );
      setState(() {
        _counter = responseMessage.afterNumber;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            // `StreamBuilder` listens to a stream
            // and rebuilds the widget accordingly.
            StreamBuilder<RustSignal>(
              // Receive signals from Rust
              // with `rustBroadcaster` from `rust_in_flutter.dart`,
              // For better performance, filter signals
              // by checking the `resource` field with the `where` method.
              // This approach allows the builder to rebuild its widget
              // only when there are signals
              // with the specific address it is interested in.
              stream: rustBroadcaster.stream.where((rustSignal) {
                return rustSignal.resource == mandelbrot.ID;
              }),
              builder: (context, snapshot) {
                // If the app has just started and widget is built
                // without receiving a Rust signal,
                // the snapshot's data will be null.
                final rustSignal = snapshot.data;
                if (rustSignal == null) {
                  // Return a black container if the received data is null.
                  return Container(
                    margin: const EdgeInsets.all(20),
                    width: 256,
                    height: 256,
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(24.0),
                      color: Colors.black,
                    ),
                  );
                } else {
                  // Return an image container if some data is received.
                  final imageData = rustSignal.blob!;
                  return Container(
                    margin: const EdgeInsets.all(20),
                    width: 256,
                    height: 256,
                    child: ClipRRect(
                      borderRadius: BorderRadius.circular(24.0),
                      child: FittedBox(
                        fit: BoxFit.contain,
                        child: Image.memory(
                          imageData,
                          width: 64,
                          height: 64,
                          gaplessPlayback: true,
                        ),
                      ),
                    ),
                  );
                }
              },
            ),
            Text(
              "Current value is $_counter",
            ),
          ],
        ),
      ),
      // This is a button that calls the increment method.
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}