Flutter插件开发：原生发送Event

目录

 

1、新建一个FlutterPlugin工程

2、编辑android原生工程

3、编辑ios原生工程

4、发布插件

1、新建一个FlutterPlugin工程

打开Android Studio后依次File-->New-->New Flutter Project-->Flutter Plugin，工程lib文件夹默认实现了一个FlutterPlugin，并且main.dart中有使用代码段。按照业务需求进行增加、修改。

FlutterPlugin类

import 'dart:async';

import 'package:flutter/services.dart';

class FlutterPlugin {
  
  StreamSubscription _event;

  initEvent() {
    //注册事件监听，设置event回调
    _event = new EventChannel("event")
        .receiveBroadcastStream()
        .listen(eventData, onError: eventError, onDone: eventDone);
  }

  /**
   *关闭并发送完成事件流，回调
   */
  void eventDone() {
    print("eventDone");
  }

  /**
   * 出错回调
   */
  void eventError(error) {
    print("eventError:$error");
  }

  /**
   * 接收数据回调
   */
  void eventData(event) {
    print("eventData:$event");
  }


  //其它代码
}

main.dart类

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

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

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State {
   @override
  void initState() {
    super.initState();
    //注册event接收
    FlutterPlugin().initEvent();
  }
//其它代码
}

2、编辑android原生工程

插件工程右键找到Flutter菜单，点击“Open Android module in Android studio”在android studio中打开Android原生工程。新版本android studio默认使用kotlin语言，使用java语言请注意区别。工程打开后flutter_plugin中找到FlutterPlugin类，工程结构如下

FlutterPlugin类

package plugin.flutter.zhou.com.flutter_plugin

import io.flutter.plugin.common.EventChannel
import io.flutter.plugin.common.EventChannel.EventSink
import io.flutter.plugin.common.EventChannel.StreamHandler
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.MethodChannel.MethodCallHandler
import io.flutter.plugin.common.MethodChannel.Result
import io.flutter.plugin.common.PluginRegistry.Registrar

class FlutterPlugin : MethodCallHandler {


    //*****************flutter调用原生******************************
    companion object {
       
        @JvmStatic
        fun registerWith(registrar: Registrar) {
            //实例化插件对象
            val plugin = FlutterPlugin()
            //调用方法注册event  handler
            plugin.register(registrar)
        }
    }

    private var eventSink: EventSink? = null;
    private val streamHandler = object : StreamHandler {
        override fun onListen(obj: Any?, sink: EventSink?) {
            eventSink = sink
        }

        override fun onCancel(obj: Any?) {
            //取消时候清空sink
            eventSink = null
        }
    }

    /**
     * 注册event Handler
     */
    fun register(registrar: Registrar) {
        //event字符串为自定义名称flutter、android、ios三端一致即可
        val eventChannel = EventChannel(registrar.messenger(), "event")
        //设置handler
        eventChannel.setStreamHandler(streamHandler)
        //测试event发送
        sendEvent("Send event data")
    }

    /**
     * 发送event,注意数据类型三端一致
     */
    fun sendEvent(event: Any) {
        eventSink?.success(event)
    }

    /*
     *处理method
     */
    override fun onMethodCall(call: MethodCall, result: Result) {
       //todo
    }
}

3、编辑ios原生工程

插件工程右键找到Flutter菜单，点击“Open IOS module in Xcode”在xcode中打开IOS原生工程。自动创建的工程没有设置Vsersion和Build，编译请注意相关错误。工程结构如下图

SwiftFlutterPlugin类

import Flutter
import UIKit

public class SwiftFlutterPlugin: NSObject,Flutter.FlutterPlugin {
    let instance = SwiftFlutterPlugin()
    //注册event
    instance.registrarEvent(registrar: registrar)
  }

   //EventStreamHandler为自定义类
   private let eventStreamHandler = EventStreamHandler()
   func registrarEvent(registrar: FlutterPluginRegistrar)  {
        //event字符串为自定义名称flutter、android、ios三端一致即可
        let eventChannel = FlutterEventChannel.init(name: "event", binaryMessenger:registrar.messenger())
        //设置handler，初学swift，是不是有其它写法？
        eventChannel.setStreamHandler((eventStreamHandler as! FlutterStreamHandler & NSObjectProtocol))
    }
 //处理method，原始工程没有if-else，笔者增加
  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    //todo
  }
}

EventStreamHandler类

//
//  EventStreamHandler.swift
//  flutter_plugin
//
//

import Foundation
class EventStreamHandler: FlutterStreamHandler {
    private var eventSink:FlutterEventSink? = nil
    func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
        eventSink = events
        return nil
    }
    
    func onCancel(withArguments arguments: Any?) -> FlutterError? {
        eventSink = nil
        return nil
    }
    
    //发送event
    public func sendEvent(event:Any) {
        eventSink?(event)
    }
}

4、发布插件

请参考社区教程