Flutter-与-原生交互（Android），字节Android高工面试

在Flutter中与Android原生代码进行交互通常涉及以下步骤：

1. 在Flutter端定义一个方法，用于启动原生模块。
2. 在Android原生项目中创建相应的Java/Kotlin类和方法来响应Flutter调用。
3. 通过MethodChannel在Flutter和原生之间发送消息。

以下是一个简单的例子：

Flutter端（Dart代码）：

import 'package:flutter/services.dart';
 
const platform = MethodChannel('samples.flutter.dev/battery');
 
// 调用原生方法获取电池信息
Future<String> getBatteryInfo() async {
  String batteryInfo;
  try {
    final String result = await platform.invokeMethod('getBatteryInfo');
    batteryInfo = "Battery Info: $result";
  } on PlatformException catch (e) {
    batteryInfo = "Failed to get battery info: '${e.message}'.";
  }
  return batteryInfo;
}

Android原生端（Java或Kotlin代码）：

import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
 
public class BatteryPlugin implements FlutterPlugin, MethodChannel.MethodCallHandler {
  private MethodChannel channel;
 
  @Override
  public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
    channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "samples.flutter.dev/battery");
    channel.setMethodCallHandler(this);
  }
 
  @Override
  public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
    if (call.method.equals("getBatteryInfo")) {
      String batteryInfo = "Battery level: " + getBatteryLevel();
      result.success(batteryInfo);
    } else {
      result.notImplemented();
    }
  }
 
  private int getBatteryLevel() {
    // 实现获取电池信息的逻辑
    return 100; // 示例返回值
  }
 
  @Override
  public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
    channel.setMethodCallHandler(null);
  }
}

确保在AndroidManifest.xml中注册插件：

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <application>
        <activity>
            ...
        </activity>
        <meta-data android:name="io.flutter.embedding.engine.FlutterEngine" android:value="com.example.BatteryPlugin" />
    </application>
</manifest>

在这个例子中，Flutter端定义了一个名为getBatteryInfo的方法，而在Android原生端，BatteryPlugin类实现了MethodCallHandler接口，并响应名为getBatteryInfo的方法调用。当Flutter调用getBatteryInfo时，Android原生端的getBatteryInfo方法会被调用，并