feat(messaging/android): pass events to Flutter

ReactNativeApp/App.tsx

@@ -15,9 +15,10 @@ import {
   ScrollView,
   StatusBar,
   Text,
+  TextInput,
   View,
 } from 'react-native';
-import { NavigationContainer, ParamListBase } from '@react-navigation/native';
+import { NavigationContainer } from '@react-navigation/native';
 import {
   createNativeStackNavigator,
   NativeStackScreenProps,
@@ -38,13 +39,14 @@ const Stack = createNativeStackNavigator();
 
 type RootStackParamList = {
   Home: { counter: number };
-  Flutter: undefined;
+  Flutter: { initialCounterValue: number };
 };
 
 function HomeScreen({
   navigation,
   route,
 }: NativeStackScreenProps<RootStackParamList, 'Home'>) {
+  const [initialCounterValue, setCounter] = useState<number>(0);
   const backgroundStyle = {
     backgroundColor: Colors.lighter,
     flex: 1,
@@ -57,13 +59,28 @@ function HomeScreen({
         style={backgroundStyle}>
         <Button
           title={'Start Flutter Screen'}
-          onPress={() => navigation.navigate('Flutter')}
+          onPress={() =>
+            navigation.navigate({
+              name: 'Flutter',
+              params: { initialCounterValue },
+              merge: true,
+            })
+          }
         />
+        <View>
+          <Text>Enter initial counter value</Text>
+          <TextInput
+            keyboardType="numeric"
+            onChangeText={text => setCounter(Number(text))}
+            value={initialCounterValue.toString()}
+            maxLength={10}
+          />
+        </View>
         <View style={{ alignSelf: 'center' }}>
           <Text>
             You have pushed the button on the Flutter screen this many times:
           </Text>
-          <Text style={{ textAlign: 'center' }}>{route.params?.counter}</Text>
+          <Text style={{ textAlign: 'center' }}>{route.params.counter}</Text>
         </View>
       </ScrollView>
     </SafeAreaView>
@@ -72,7 +89,8 @@ function HomeScreen({
 
 function FlutterScreenWrapper({
   navigation,
-}: NativeStackScreenProps<ParamListBase>) {
+  route,
+}: NativeStackScreenProps<RootStackParamList, 'Flutter'>) {
   const [counter, setCounter] = useState<number>(0);
   const onCounterIncrement = (value: number) => {
     console.log(`onCounterIncrement: ${value}`);
@@ -84,6 +102,7 @@ function FlutterScreenWrapper({
   }, [counter, navigation]);
   return (
     <FlutterScreen
+      initialCounterValue={route.params.initialCounterValue}
       onCounterIncrement={onCounterIncrement}
       onScreenClose={onScreenClose}
     />
@@ -99,7 +118,11 @@ const App: React.FC = () => {
           component={HomeScreen}
           initialParams={{ counter: 0 }}
         />
-        <Stack.Screen name="Flutter" component={FlutterScreenWrapper} />
+        <Stack.Screen
+          name="Flutter"
+          component={FlutterScreenWrapper}
+          initialParams={{ initialCounterValue: 0 }}
+        />
       </Stack.Navigator>
     </NavigationContainer>
   );

flutter_module_rn/android-rn/src/main/java/com/reactlibrary/FlutterModuleActivity.java

@@ -1,5 +1,7 @@
 package com.reactlibrary;
 
+import android.os.Bundle;
+
 import androidx.annotation.NonNull;
 import io.flutter.embedding.android.FlutterActivity;
 import io.flutter.embedding.engine.FlutterEngine;
@@ -11,6 +13,9 @@
 public class FlutterModuleActivity extends FlutterActivity {
     private static final String CHANNEL = "pavel/flutter";
 
+    public static final String INITIAL_EVENT = "INITIAL_EVENT";
+    public static final String INITIAL_ARGS = "INITIAL_ARGS";
+
     // React Native event emitter. Uset to send events to the host React Native app
     private DeviceEventManagerModule.RCTDeviceEventEmitter reactNativeEventEmitter = null;
 
@@ -39,4 +44,16 @@ public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
                 }
         );
     }
+
+    @Override
+    public void onFlutterUiDisplayed() {
+        Bundle extras = this.getIntent().getExtras();
+        String eventName = extras.getString(INITIAL_EVENT);
+        String args = extras.getString(INITIAL_ARGS);
+        sendEventToFlutter(eventName, args);
+    }
+
+    public void sendEventToFlutter(String eventName, String args) {
+        channel.invokeMethod(eventName, args);
+    }
 }

flutter_module_rn/android-rn/src/main/java/com/reactlibrary/FlutterModuleRnModule.java

@@ -30,14 +30,34 @@ public String getName() {
     }
 
     @ReactMethod
-    public void startFlutterActivity(String stringArgument, int numberArgument, Callback callback) {
+    public void startFlutterActivity(String eventName, String args, Callback callback) {
         Activity currentActivity = reactContext.getCurrentActivity();
         // we can pass arguments to the Intent
         currentActivity.startActivity(
                 new FlutterActivity
                         .NewEngineIntentBuilder(FlutterModuleActivity.class)
                         .build(currentActivity)
+                        .putExtra(FlutterModuleActivity.INITIAL_EVENT, eventName)
+                        .putExtra(FlutterModuleActivity.INITIAL_ARGS, args)
         );
-        callback.invoke("Received numberArgument: " + numberArgument + " stringArgument: " + stringArgument);
+        callback.invoke("Received eventName: " + eventName + ", args: " + args);
+    }
+
+    @ReactMethod
+    public void sendEvent(String eventName, String args) {
+        Activity currentActivity = reactContext.getCurrentActivity();
+        if (currentActivity instanceof FlutterModuleActivity) {
+            ((FlutterModuleActivity) currentActivity).sendEventToFlutter(eventName, args);
+        }
+    }
+
+    @ReactMethod
+    public void addListener(String eventName) {
+        // Keep: Required for RN built in Event Emitter Calls.
+    }
+
+    @ReactMethod
+    public void removeListeners(Integer count) {
+        // Keep: Required for RN built in Event Emitter Calls.
     }
 }

flutter_module_rn/lib/main.dart

@@ -49,6 +49,20 @@ class _MyHomePageState extends State<MyHomePage> {
   static const platform = MethodChannel('pavel/flutter');
 
   int _counter = 0;
+  bool _received = false;
+
+  @override
+  void initState() {
+    platform.setMethodCallHandler((call) async {
+      if (call.method == 'setCounterValue') {
+        setState(() {
+          _received = true;
+          _counter = int.parse(call.arguments as String);
+        });
+      }
+    });
+    super.initState();
+  }
 
   void _incrementCounter() {
     setState(() {
@@ -107,6 +121,7 @@ class _MyHomePageState extends State<MyHomePage> {
             const Text(
               'You have pushed the button this many times:',
             ),
+            if (_received) const Text('(counter set from initial value)'),
             Text(
               '$_counter',
               style: Theme.of(context).textTheme.headline4,

flutter_module_rn/src/FlutterScreen/index.d.ts

@@ -1,12 +1,14 @@
 import * as React from 'react'
 
 interface FlutterModuleRn {
-  startFlutterActivity: (arg1: string, arg2: number, callback: (text: string) => void) => void;
+  startFlutterActivity: (initialEvent: string, args: string, callback: (text: string) => void) => void;
+  sendEvent: (event: string, args?: string) => void;
 }
 
 interface FlutterScreenProps {
   onCounterIncrement: (value: number) => void;
   onScreenClose: () => void;
+  initialCounterValue: number;
 }
 
 declare const FlutterScreen: React.FC<FlutterScreenProps>

flutter_module_rn/src/FlutterScreen/index.js

@@ -2,15 +2,15 @@ import { ActivityIndicator, NativeEventEmitter, NativeModules, Platform, Text, V
 import React, { useEffect } from 'react'
 
 const { FlutterModuleRn } = NativeModules;
+const eventEmitter = new NativeEventEmitter(FlutterModuleRn);
 
-const FlutterScreen = ({ onCounterIncrement, onScreenClose }) => {
+const FlutterScreen = ({ initialCounterValue, onCounterIncrement, onScreenClose }) => {
   useEffect(() => {
-    FlutterModuleRn.startFlutterActivity('', 0, (text) => {
+    FlutterModuleRn.startFlutterActivity('setCounterValue', initialCounterValue.toString(), (text) => {
       console.log(text);
     });
   }, [])
   useEffect(() => {
-    const eventEmitter = new NativeEventEmitter(FlutterModuleRn);
     const listener1 = eventEmitter.addListener('incrementCounter', (event) => {
       onCounterIncrement(event);
     });