平台通信的3中方式
-
MethodChannel：Flutter 与 Native 端相互调用，调用后可以返回结果，可以 Native 端主动调用，也可以Flutter主动调用，属于双向通信。此方式为最常用的方式， Native 端调用需要在主线程中执行。
-
BasicMessageChannel：用于使用指定的编解码器对消息进行编码和解码，属于双向通信，可以 Native 端主动调用，也可以Flutter主动调用。
-
EventChannel：用于数据流（event streams）的通信， Native 端主动发送数据给 Flutter，通常用于状态的监听，比如网络变化、传感器数据等。
通信架构图
通信与平台线程
Handler(Looper.getMainLooper()).post {
}
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
}
});
activity.runOnUiThread {
}
dispatch_async(dispatch_get_main_queue(),^{
});
DispatchQueue.main.async {
}
MethodChannel
Flutter 端
var channel = MethodChannel('com.flutter.guide.MethodChannel');
var result = await channel.invokeMethod('sendData',{'name': 'laomeng','age': 18})
- 第一个参数表示method，方法名称，原生端会解析此参数。
- 第二个参数表示参数，类型任意，多个参数通常使用Map。
- 返回 Future，原生端返回的数据。
class MethodChannelDemo extends StatefulWidget {
@override
_MethodChannelDemoState createState() => _MethodChannelDemoState();
}
class _MethodChannelDemoState extends State<MethodChannelDemo> {
var channel = MethodChannel('com.flutter.guide.MethodChannel');
var _data;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),body: Column(
children: [
SizedBox(
height: 50,),RaisedButton(
child: Text('发送数据到原生'),onPressed: () async {
var result = await channel
.invokeMethod('sendData','age': 18});
var name = result['name'];
var age = result['age'];
setState(() {
_data = '$name,$age';
});
},Text('原生返回数据：$_data')
],);
}
}
Android 端
package com.flutter.guide
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
/**
* des:
*/
class MethodChannelDemo(messenger: BinaryMessenger): MethodChannel.MethodCallHandler {
private var channel: MethodChannel
init {
channel = MethodChannel(messenger,"com.flutter.guide.MethodChannel")
channel.setMethodCallHandler(this)
}
override fun onMethodCall(call: MethodCall,result: MethodChannel.Result) {
}
}
override fun onMethodCall(call: MethodCall,result: MethodChannel.Result) {
if (call.method == "sendData") {
val name = call.argument("name") as String?
val age = call.argument("age") as Int?
var map = mapOf("name" to "hello,$name","age" to "$age"
)
result.success(map)
}
}
-
call.method 字符串就是 invokeMethod 方法传入的 method。
-
call.argument 是 invokeMethod 传入的参数，由于 Flutter 端传入的是 Map，所以上面的解析按照 Map 解析。
-
result.success() 是返回给 Flutter 的结果。
var result = await channel
.invokeMethod('sendData','age': 18});
var name = result['name'];
var age = result['age'];
class MainActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
MethodChannelDemo(flutterEngine.dartExecutor.binaryMessenger)
}
}
iOS 端
import Flutter
import UIKit
public class MethodChannelDemo {
init(messenger: FlutterBinaryMessenger) {
let channel = FlutterMethodChannel(name: "com.flutter.guide.MethodChannel",binaryMessenger: messenger)
channel.setMethodCallHandler { (call:FlutterMethodCall,result:@escaping FlutterResult) in
if (call.method == "sendData") {
if let dict = call.arguments as? Dictionary<String,Any> {
let name:String = dict["name"] as? String ?? ""
let age:Int = dict["age"] as? Int ?? -1
result(["name":"hello,\(name)","age":age])
}
}
}
}
}
import UIKit
import Flutter
@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
override func application(
_ application: UIApplication,didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
MethodChannelDemo(messenger: controller.binaryMessenger)
GeneratedPluginRegistrant.register(with: self)
return super.application(application,didFinishLaunchingWithOptions: launchOptions)
}
}
原生端主动发送消息给Flutter
Flutter 端接收数据
@override
void initState() {
super.initState();
channel.setMethodCallHandler((call) {
setState(() {
_nativeData = call.arguments['count'];
});
});
}
Android 发送数据
class MethodChannelDemo(var activity: Activity,messenger: BinaryMessenger) : MethodChannel.MethodCallHandler {
private var channel: MethodChannel
private var count = 0
init {
channel = MethodChannel(messenger,"com.flutter.guide.MethodChannel")
channel.setMethodCallHandler(this)
startTimer()
}
fun startTimer() {
var timer = Timer().schedule(timerTask {
activity.runOnUiThread {
var map = mapOf("count" to count++)
channel.invokeMethod("timer",map)
}
},1000)
}
override fun onMethodCall(call: MethodCall,result: MethodChannel.Result) {
if (call.method == "sendData") {
val name = call.argument("name") as String?
val age = call.argument("age") as Int?
var map = mapOf("name" to "hello,"age" to "$age"
)
result.success(map)
}
}
}
class MainActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
MethodChannelDemo(this,flutterEngine.dartExecutor.binaryMessenger)
flutterEngine.plugins.add(MyPlugin())
}
}
iOS 发送数据
import Flutter
import UIKit
public class MethodChannelDemo {
var count = 0
var channel:FlutterMethodChannel
init(messenger: FlutterBinaryMessenger) {
channel = FlutterMethodChannel(name: "com.flutter.guide.MethodChannel","age":age])
}
}
}
startTimer()
}
func startTimer() {
var timer = Timer.scheduledTimer(timeInterval:1,target: self,selector:#selector(self.tickDown),userInfo:nil,repeats: true)
}
@objc func tickDown(){
count += 1
var args = ["count":count]
channel.invokeMethod("timer",arguments:args)
}
}
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