<aside> 💡 flutter stable channel 에서 테스트 하자.

아래 3단계를 거치면 된다. flutter channel stable

flutter clean flutter pub get

</aside>

1. 프로젝트 생성

native_channel_test1 프로젝트 생성

꼭 언어는 Java 선택!!

2. MainActivity

package com.example.native_channel_test1;

import androidx.annotation.NonNull;
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugin.common.MethodChannel;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.BatteryManager;
import android.content.ContextWrapper;
import android.content.Intent;
import android.content.IntentFilter;

// <https://docs.flutter.dev/platform-integration/platform-channels>
public class MainActivity extends FlutterActivity {
    private static final String CHANNEL = "samples.flutter.dev/battery";

    @Override
    public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
        super.configureFlutterEngine(flutterEngine);
        new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL)
                .setMethodCallHandler(
                        (call, result) -> {
                            // This method is invoked on the main thread.
                            if (call.method.equals("getBatteryLevel")) {
                                int batteryLevel = getBatteryLevel();

                                if (batteryLevel != -1) {
                                    result.success(batteryLevel);
                                } else {
                                    result.error("UNAVAILABLE", "Battery level not available.", null);
                                }
                            } else {
                                result.notImplemented();
                            }
                        }
                );
    }

    private int getBatteryLevel() {
        int batteryLevel = -1;
        if (VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP) {
            BatteryManager batteryManager = (BatteryManager) getSystemService(BATTERY_SERVICE);
            batteryLevel = batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY);
        } else {
            Intent intent = new ContextWrapper(getApplicationContext()).
                    registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
            batteryLevel = (intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) * 100) /
                    intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
        }

        return batteryLevel;
    }
}

3. lib/main.dart

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

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {

  static const platform = MethodChannel('samples.flutter.dev/battery');

  String _batteryLevel = 'Unknown battery level.';

  Future<void> _getBatteryLevel() async {
    String batteryLevel;
    try {
      final result = await platform.invokeMethod<int>('getBatteryLevel');
      batteryLevel = 'Battery level at $result % .';
    } on PlatformException catch (e) {
      batteryLevel = "Failed to get battery level: '${e.message}'.";
    }

    setState(() {
      _batteryLevel = batteryLevel;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Material(
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            ElevatedButton(
              onPressed: _getBatteryLevel,
              child: const Text('Get Battery Level'),
            ),
            Text(_batteryLevel),
          ],
        ),
      ),
    );
  }
}

4. 배터리 레벨 낮춰서 테스트해보기