flutter和Android原生交互的三种方式

在Flutter中，与Android原生代码交互主要有三种方式：MethodChannel、EventChannel和BasicMessageChannel。

1. MethodChannel：用于传递方法调用（方法和回调）。

在Flutter端：

const platform = MethodChannel('samples.flutter.dev/battery');
 
String _getBatteryLevel() {
  String batteryLevel;
  try {
    final int result = await platform.invokeMethod('getBatteryLevel');
    batteryLevel = 'Battery level at $result% .';
  } on PlatformException catch (e) {
    batteryLevel = "Failed to get battery level: '${e.message}'.";
  }
  return batteryLevel;
}

在Android端：

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import android.os.Bundle;
 
public class MainActivity extends FlutterActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
 
    new MethodChannel(getFlutterView(), "samples.flutter.dev/battery").setMethodCallHandler(
      new MethodChannel.MethodCallHandler() {
        @Override
        public void onMethodCall(MethodCall call, MethodChannel.Result result) {
          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() {
    // ...获取电池电量的逻辑
    return 100; // 假设的返回值
  }
}

2. EventChannel：用于数据流的通信。

在Flutter端：

const EventChannel battery = EventChannel('samples.flutter.dev/batteryStatus');
 
Stream<String> get batteryState {
  return battery.receiveBroadcastStream().map((buffer) => _parseEvent(buffer));
}
 
String _parseEvent(dynamic event) {
  // 解析事件的逻辑
  return "Event: $event";
}

在Android端：

import io.flutter.plugin.common.EventChannel;
import io.flutter.view.FlutterView;
import android.os.Bundle;
 
public class MainActivity extends FlutterActivity {
  @Ov