main.dart

import 'dart:typed_data';

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Tflite add',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _left = "1.2";
  String _right = "3.4";
  String _output = "";
  FirebaseModelInterpreter interpreter = FirebaseModelInterpreter.instance;
  FirebaseModelManager manager = FirebaseModelManager.instance;

  Future<void> initTflite() {
    return this.manager.registerRemoteModelSource(
          FirebaseRemoteModelSource(
            modelName: "add",
            enableModelUpdates: true,
          ),
        );
  }

  void _onLeftOpChanged(String op) {
    setState(() {
      _left = op;
    });
  }

  void _onRightOpChanged(String op) {
    setState(() {
      _right = op;
    });
  }

  @override
  void initState() {
    super.initState();
    initTflite();
  }

  void _onActionButtonPressed() async {
    final leftNum = double.parse(_left);
    final rightNum = double.parse(_right);

    const ROW = 2;
    const COLUMN = 5;

    const options = FirebaseModelInputOutputOptions([
      FirebaseModelIOOption(FirebaseModelDataType.FLOAT32, [ROW, COLUMN]),
      FirebaseModelIOOption(FirebaseModelDataType.FLOAT32, [ROW, COLUMN]),
    ], [
      FirebaseModelIOOption(FirebaseModelDataType.FLOAT32, [ROW, COLUMN]),
    ]);

    final left = List<double>(ROW * COLUMN);
    final right = List<double>(ROW * COLUMN);
    for (var i = 0; i < ROW; i++) {
      for (var j = 0; j < COLUMN; j++) {
        left[COLUMN * i + j] = leftNum;
        right[COLUMN * i + j] = rightNum;
      }
    }
    final concat = <double>[]..addAll(left)..addAll(right);
    print(concat);
    final input = float32ListToUint8List(Float32List.fromList(concat));
    print(input);

    final output = await this.interpreter.run("add", options, input);
    print(output);

    setState(() {
      _output = (output[0][0][0] as double).toStringAsFixed(2);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              TextField(
                decoration: InputDecoration(
                  labelText: 'left-hand operand',
                ),
                onChanged: _onLeftOpChanged,
                keyboardType: TextInputType.numberWithOptions(
                  signed: true,
                  decimal: true,
                ),
              ),
              TextField(
                decoration: InputDecoration(
                  labelText: 'right-hand operand',
                ),
                onChanged: _onRightOpChanged,
                keyboardType: TextInputType.numberWithOptions(
                  signed: true,
                  decimal: true,
                ),
              ),
              Padding(
                padding: const EdgeInsets.only(top: 32.0),
                child: Text(
                  _output,
                  style: Theme.of(context).textTheme.display1,
                ),
              ),
            ],
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _onActionButtonPressed,
        tooltip: 'Execute',
        child: Icon(Icons.add),
      ),
    );
  }
}

Uint8List float32ListToUint8List(Float32List list) {
  return list.buffer.asUint8List();
}