Flutter和原生之间进行通信可以通过以下几种方式：
Flutter MethodChannel：Flutter提供了MethodChannel来实现Flutter与原生平台的双向方法调用。我们可以在Flutter中创建一个MethodChannel对象，并定义方法的名称和参数。然后在原生代码中注册相应的方法处理程序，当Flutter调用该方法时，原生代码会执行相应的操作，并返回结果给Flutter。
Flutter EventChannel：EventChannel用于在Flutter和原生之间传递事件流。我们可以在Flutter中创建一个EventChannel对象，并定义事件的名称和参数。然后在原生代码中监听该事件，并在特定条件下发送事件给Flutter。
PlatformView：如果你需要在Flutter中使用原生控件或视图，可以使用PlatformView。它允许我们在Flutter中嵌入原生视图，并与其进行交互。
Flutter Plugin：如果需要更复杂的功能或者想要封装一些原生功能为Flutter插件，可以创建一个Flutter插件。Flutter插件允许我们在Flutter和原生之间建立更高级的通信机制，并提供一致的API给Flutter开发者使用。
这些是常见的Flutter和原生通信方式，具体的选择取决于实际需求和场景。
下面是简单的demo实现：
首先是MethodChannel的方式：
在Flutter中，可以使用MethodChannel来实现与原生平台（如安卓和iOS）的通信。下面是一个简单的代码示例：
首先，在Flutter端创建一个MethodChannel对象，并定义与原生平台通信的方法：
首先dart代码实现：
import 'package:flutter/services.dart';
// 创建MethodChannel对象
MethodChannel _channel = MethodChannel('com.example.channel');
// 定义与原生平台通信的方法
Future<void> sendMessageToNative(String message) async {
try {
// 调用原生平台的方法
await _channel.invokeMethod('sendMessage', {'message': message});
} catch (e) {
print('Error: $e');
}
}
然后，在原生平台的代码中注册MethodChannel，并处理Flutter端发送的消息：
在安卓端（Java）的代码示例：
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
public class MainActivity extends FlutterActivity {
private static final String CHANNEL = "com.example.channel";
// 创建MethodChannel对象
private MethodChannel methodChannel;
@Override
public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
super.configureFlutterEngine(flutterEngine);
// 注册MethodChannel
methodChannel = new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL);
//接受flutter消息
methodChannel.setMethodCallHandler(new MethodCallHandler() {
@Override
public void onMethodCall(MethodCall call, Result result) {
if (call.method.equals("sendMessage")) {
String message = call.argument("message");
// 处理Flutter端发送的消息
handleSendMessage(message);
result.success(null); // 返回结果给Flutter端
} else {
result.notImplemented();
}
}
});
/*
//发送给flutter消息
String message = "Hello from Android";
// 发送消息给Flutter端
methodChannel.invokeMethod("sendMessage", message);
*/
}
private void handleSendMessage(String message) {
// 处理接收到的消息
System.out.println("Received message from Flutter: " + message);
}
}
在iOS端（Objective-C）的代码示例：
#import "AppDelegate.h"
#import <Flutter/Flutter.h>
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
FlutterViewController* flutterViewController = (FlutterViewController*)self.window.rootViewController;
// 注册MethodChannel
FlutterMethodChannel* channel = [FlutterMethodChannel
methodChannelWithName:@"com.example.channel"
binaryMessenger:flutterViewController.binaryMessenger];
[channel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
if ([call.method isEqualToString:@"sendMessage"]) {
NSString* message = call.arguments[@"message"];
// 处理Flutter端发送的消息
[self handleSendMessage:message];
result(nil); // 返回结果给Flutter端
} else {
result(FlutterMethodNotImplemented);
}
}];
/*
// 发送消息给Flutter端
[channel invokeMethod:@"sendMessage" arguments:message];
*/
return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
- (void)handleSendMessage:(NSString*)message {
// 处理接收到的消息
NSLog(@"Received message from Flutter: %@", message);
}
@end
//
//
//
然后是使用EventChannel进行通信
dart代码：
import 'package:flutter/services.dart';
// 创建EventChannel对象
EventChannel _eventChannel = EventChannel('com.example.channel');
// 定义与原生平台通信的事件流
Stream<dynamic> receiveMessageFromNative() {
// 监听原生平台发送的事件
return _eventChannel.receiveBroadcastStream();
}
安卓代码：
import io.flutter.plugin.common.EventChannel;
public class MainActivity extends FlutterActivity {
private static final String CHANNEL = "com.example.channel";
@Override
public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
super.configureFlutterEngine(flutterEngine);
// 注册EventChannel
new EventChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL)
.setStreamHandler(new EventChannel.StreamHandler() {
private EventChannel.EventSink eventSink;
@Override
public void onListen(Object arguments, EventChannel.EventSink sink) {
eventSink = sink;
// 发送事件给Flutter端
sendMessageToFlutter("Hello from Android");
}
@Override
public void onCancel(Object arguments) {
eventSink = null;
}
private void sendMessageToFlutter(String message) {
if (eventSink != null) {
eventSink.success(message); // 发送事件给Flutter端
}
}
});
}
}
iOS代码：
#import "AppDelegate.h"
#import <Flutter/Flutter.h>
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
FlutterViewController* flutterViewController = (FlutterViewController*)self.window.rootViewController;
// 注册EventChannel
FlutterEventChannel* channel = [FlutterEventChannel
eventChannelWithName:@"com.example.channel"
binaryMessenger:flutterViewController.binaryMessenger];
[channel setStreamHandler:self];
return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
#pragma mark - FlutterStreamHandler
- (FlutterError *)onListenWithArguments:(id)arguments eventSink:(FlutterEventSink)eventSink {
// 发送事件给Flutter端
[self sendMessageToFlutter:@"Hello from iOS" eventSink:eventSink];
return nil;
}
- (FlutterError *)onCancelWithArguments:(id)arguments {
return nil;
}
- (void)sendMessageToFlutter:(NSString *)message eventSink:(FlutterEventSink)eventSink {
if (eventSink) {
eventSink(message); // 发送事件给Flutter端
}
}
@end
然后是使用PlatformView与原生进行通信
它本质上也是用的MethodChannel或者EventChannel进行通信
首先，在Flutter端创建一个PlatformView，并定义与原生通信的方法：
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
class NativeView extends StatefulWidget {
@override
_NativeViewState createState() => _NativeViewState();
}
class _NativeViewState extends State<NativeView> {
// 创建MethodChannel对象
MethodChannel _methodChannel = MethodChannel('com.example.native_view');
// 定义与原生通信的方法
Future<void> sendMessageToNative(String message) async {
try {
// 调用原生平台的方法
await _methodChannel.invokeMethod('sendMessage', {'message': message});
} catch (e) {
print('Error: $e');
}
}
@override
Widget build(BuildContext context) {
return AndroidView(
viewType: 'com.example.native_view',
creationParamsCodec: const StandardMessageCodec(),
onPlatformViewCreated: (int id) {
// 原生视图创建完成后，可以进行一些初始化操作
},
);
}
}
然后，在原生平台的代码中创建并注册PlatformView，并处理Flutter端发送的消息：
在安卓端（Java）的代码示例：
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.StandardMessageCodec;
public class MainActivity extends FlutterActivity {
private static final String CHANNEL = "com.example.native_view";
@Override
public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
super.configureFlutterEngine(flutterEngine);
// 注册PlatformView
flutterEngine.getPlatformViewsController().getRegistry().registerViewFactory(CHANNEL, new NativeViewFactory());
// 创建MethodChannel对象
MethodChannel methodChannel = new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL);
methodChannel.setMethodCallHandler((call, result) -> {
if (call.method.equals("sendMessage")) {
String message = call.argument("message");
// 处理Flutter端发送的消息
handleSendMessage(message);
result.success(null); // 返回结果给Flutter端
} else {
result.notImplemented();
}
});
}
private void handleSendMessage(String message) {
// 处理接收到的消息
System.out.println("Received message from Flutter: " + message);
}
}
在iOS端（Objective-C）的代码示例
#import "AppDelegate.h"
#import <Flutter/Flutter.h>
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
FlutterViewController* flutterViewController = (FlutterViewController*)self.window.rootViewController;
// 注册PlatformView
[flutterViewController.platformViewRegistry registerViewFactory:@"com.example.native_view" withBlock:^(id<FlutterBinaryMessenger> messenger, id arguments) {
return [[NativeView alloc] initWithMessenger:messenger];
}];
// 创建MethodChannel对象
FlutterMethodChannel* methodChannel = [FlutterMethodChannel methodChannelWithName:@"com.example.native_view" binaryMessenger:flutterViewController.binaryMessenger];
[methodChannel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
if ([call.method isEqualToString:@"sendMessage"]) {
NSString* message = call.arguments[@"message"];
// 处理Flutter端发送的消息
[self handleSendMessage:message];
result(nil); // 返回结果给Flutter端
} else {
result(FlutterMethodNotImplemented);
}
}];
return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
- (void)handleSendMessage:(NSString*)message {
// 处理接收到的消息
NSLog(@"Received message from Flutter: %@", message);
}
@end
//
//
//
最后是使用Flutter Plugin进行通信
首先，在Flutter端创建一个Flutter插件，并定义与原生通信的方法：
import 'package:flutter/services.dart';
class MyPlugin {
static const MethodChannel _channel = MethodChannel('my_plugin');
static Future<String> getPlatformVersion() async {
final String version = await _channel.invokeMethod('getPlatformVersion');
return version;
}
static Future<void> sendMessageToNative(String message) async {
await _channel.invokeMethod('sendMessage', {'message': message});
}
}
然后，在原生平台（安卓或iOS）的代码中实现Flutter插件的功能：
在安卓端（Java）的代码示例：
import io.flutter.embedding.engine.plugins.FlutterPlugin;
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;
public class MyPlugin implements FlutterPlugin, MethodCallHandler {
private MethodChannel methodChannel;
@Override
public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
methodChannel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "my_plugin");
methodChannel.setMethodCallHandler(this);
}
@Override
public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
if (call.method.equals("getPlatformVersion")) {
String version = "Android " + android.os.Build.VERSION.RELEASE;
result.success(version);
} else if (call.method.equals("sendMessage")) {
String message = call.argument("message");
// 处理Flutter端发送的消息
handleSendMessage(message);
result.success(null);
} else {
result.notImplemented();
}
}
private void handleSendMessage(String message) {
// 处理接收到的消息
System.out.println("Received message from Flutter: " + message);
}
@Override
public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
methodChannel.setMethodCallHandler(null);
}
}
在iOS端（Objective-C）的代码示例：
#import <Flutter/Flutter.h>
@interface MyPlugin : NSObject<FlutterPlugin>
@end
@implementation MyPlugin
+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
FlutterMethodChannel* channel = [FlutterMethodChannel
methodChannelWithName:@"my_plugin"
binaryMessenger:[registrar messenger]];
MyPlugin* instance = [[MyPlugin alloc] init];
[registrar addMethodCallDelegate:instance channel:channel];
}
- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
if ([call.method isEqualToString:@"getPlatformVersion"]) {
NSString* version = [NSString stringWithFormat:@"iOS %@", [[UIDevice currentDevice] systemVersion]];
result(version);
} else if ([call.method isEqualToString:@"sendMessage"]) {
NSString* message = call.arguments[@"message"];
// 处理Flutter端发送的消息
[self handleSendMessage:message];
result(nil);
} else {
result(FlutterMethodNotImplemented);
}
}
- (void)handleSendMessage:(NSString*)message {
// 处理接收到的消息
NSLog(@"Received message from Flutter: %@", message);
}
@end
