Flutter 混合开发系列 包含以下：android
嵌入原生View-Android 嵌入原生View-iOS 与原生通讯-MethodChannel 与原生通讯-BasicMessageChannel 与原生通讯-EventChannel 添加 Flutter 到 Android Activity 添加 Flutter 到 Android Fragment 添加 Flutter 到 iOS 每一个工做日分享一篇，欢迎关注、点赞及转发。ios
平台通讯的3中方式
Flutter 与 Native 端通讯有以下3个方法：web
-
MethodChannel：Flutter 与 Native 端相互调用，调用后能够返回结果，能够 Native 端主动调用，也能够Flutter主动调用，属于双向通讯。此方式为最经常使用的方式， Native 端调用须要在主线程中执行。 -
BasicMessageChannel：用于使用指定的编解码器对消息进行编码和解码，属于双向通讯，能够 Native 端主动调用，也能够Flutter主动调用。 -
EventChannel：用于数据流（event streams）的通讯， Native 端主动发送数据给 Flutter，一般用于状态的监听，好比网络变化、传感器数据等。
Flutter 端
Flutter 端建立 MethodChannel 通道，用于与原生端通讯：微信
var channel = BasicMessageChannel('com.flutter.guide.BasicMessageChannel',StandardMessageCodec());
com.flutter.guide.BasicMessageChannel 是 BasicMessageChannel 的名称，原生端要与之对应。网络
发送消息：app
var result = await channel.send({'name': 'laomeng', 'age': 18});
-
参数类型任意，多个参数一般使用 Map。 -
返回 Future，原生端返回的数据。
完整代码：async
class BasicMessageChannelDemo extends StatefulWidget {
@override
_BasicMessageChannelDemoState createState() => _BasicMessageChannelDemoState();
}
class _BasicMessageChannelDemoState extends State<BasicMessageChannelDemo> {
var channel = BasicMessageChannel('com.flutter.guide.BasicMessageChannel',StandardMessageCodec());
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.send({'name': 'laomeng', 'age': 18});
var name = result['name'];
var age = result['age'];
setState(() {
_data = '$name,$age';
});
},
),
Text('原生返回数据：$_data'),
],
),
);
}
}
Android 端
android 下建立 BasicMessageChannelDemo：编辑器
class BasicMessageChannelDemo(messenger: BinaryMessenger) : BasicMessageChannel.MessageHandler<Any> {
private var channel: BasicMessageChannel<Any>
init {
channel = BasicMessageChannel(messenger, "com.flutter.guide.BasicMessageChannel", StandardMessageCodec())
channel.setMessageHandler(this)
}
override fun onMessage(message: Any?, reply: BasicMessageChannel.Reply<Any>) {
val name = (message as Map<String, Any>)["name"]
val age = (message as Map<String, Any>)["age"]
var map = mapOf("name" to "hello,$name",
"age" to "$age"
)
reply.reply(map)
}
}
onMessage 方法在 Flutter 端调用 send 方法后调用，解析方法以下：ide
override fun onMessage(message: Any?, reply: BasicMessageChannel.Reply<Any>) {
val name = (message as Map<String, Any>)["name"]
val age = (message as Map<String, Any>)["age"]
var map = mapOf("name" to "hello,$name",
"age" to "$age"
)
reply.reply(map)
}
-
message 是传入的参数，因为 Flutter 端传入的是 Map，因此上面的解析按照 Map 解析。 -
reply.reply() 是返回给 Flutter 的结果。
Flutter 端解析：flex
var result = await channel.send({'name': 'laomeng', 'age': 18});
var name = result['name'];
var age = result['age'];
两端的解析要相互对应。
在 MainActivity 启动：
class MainActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
BasicMessageChannelDemo(flutterEngine.dartExecutor.binaryMessenger)
flutterEngine.plugins.add(MyPlugin())
}
}
iOS 端
ios 下建立 MethodChannelDemo，按以下方式：
import Flutter
import UIKit
public class BasicMessageChannelDemo {
var channel:FlutterBasicMessageChannel
init(messenger: FlutterBinaryMessenger) {
channel = FlutterBasicMessageChannel(name: "com.flutter.guide.BasicMessageChannel", binaryMessenger: messenger)
channel.setMessageHandler { (message, reply) in
if let dict = message as? Dictionary<String, Any> {
let name:String = dict["name"] as? String ?? ""
let age:Int = dict["age"] as? Int ?? -1
reply(["name":"hello,\(name)","age":age])
}
}
}
}
在 AppDelegate 启动：
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)
BasicMessageChannelDemo(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.setMessageHandler((message) {
setState(() {
_nativeData = message['count'];
});
});
}
Android 发送数据
原生端启动定时器，每隔一秒向 Flutter 发送数据，Android 端代码：
class BasicMessageChannelDemo(var activity: Activity, messenger: BinaryMessenger) : BasicMessageChannel.MessageHandler<Any> {
private var channel: BasicMessageChannel<Any>
private var count = 0
init {
channel = BasicMessageChannel(messenger, "com.flutter.guide.BasicMessageChannel", StandardMessageCodec())
channel.setMessageHandler(this)
startTimer()
}
fun startTimer() {
var timer = Timer().schedule(timerTask {
activity.runOnUiThread {
var map = mapOf("count" to count++)
channel.send(map,object :BasicMessageChannel.Reply<Any>{
override fun reply(reply: Any?) {
}
})
}
}, 0, 1000)
}
override fun onMessage(message: Any?, reply: BasicMessageChannel.Reply<Any>) {
val name = (message as Map<String, Any>)["name"]
val age = (message as Map<String, Any>)["age"]
var map = mapOf("name" to "hello,$name",
"age" to "$age"
)
reply.reply(map)
}
}
注意：Android 端发送数据要在主现场中调用，即：
activity.runOnUiThread {
var map = mapOf("count" to count++)
channel.invokeMethod("timer", map)
}
启动修改以下：
class MainActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
BasicMessageChannelDemo(this,flutterEngine.dartExecutor.binaryMessenger)
flutterEngine.plugins.add(MyPlugin())
}
}
iOS 发送数据
iOS 端启动定时器代码以下：
import Flutter
import UIKit
public class BasicMessageChannelDemo {
var channel:FlutterBasicMessageChannel
var count = 0
init(messenger: FlutterBinaryMessenger) {
channel = FlutterBasicMessageChannel(name: "com.flutter.guide.BasicMessageChannel", binaryMessenger: messenger)
channel.setMessageHandler { (message, reply) in
if let dict = message as? Dictionary<String, Any> {
let name:String = dict["name"] as? String ?? ""
let age:Int = dict["age"] as? Int ?? -1
reply(["name":"hello,\(name)","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.sendMessage(args) { (reply) in
}
}
}
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