[example][android] Add foreground service example

example/android/app/src/main/AndroidManifest.xml

@@ -1,8 +1,11 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="io.agora.agora_rtc_ng_example">
+
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+
    <application
         android:label="agora_rtc_ng_example"
-        android:name="${applicationName}"
+        android:name=".MyApplication"
         android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"
@@ -30,5 +33,11 @@
         <meta-data
             android:name="flutterEmbedding"
             android:value="2" />
+
+       <service
+           android:name=".ExampleService"
+           android:exported="false"
+           android:foregroundServiceType="mediaPlayback|microphone"
+           android:stopWithTask="false" />
     </application>
 </manifest>

example/android/app/src/main/kotlin/io/agora/agora_rtc_flutter_example/ExampleService.kt

@@ -0,0 +1,158 @@
+package io.agora.agora_rtc_ng_example
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.os.Binder
+import android.os.Build
+import android.os.Bundle
+import android.os.IBinder
+import androidx.core.app.NotificationCompat
+import androidx.core.content.ContextCompat
+
+class ExampleService: Service() {
+
+    private val binder: Binder by lazy {
+        Binder()
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        return if (intent?.action == ACTION_START_FOREGROUND_SERVICE) {
+            startForegroundService()
+            START_REDELIVER_INTENT
+        } else {
+            stopForegroundService()
+            START_NOT_STICKY
+        }
+    }
+
+    override fun onTaskRemoved(rootIntent: Intent?) {
+        super.onTaskRemoved(rootIntent)
+        // If we receive the `onTaskRemoved`, we consider that the user want to close the APP, so
+        // destroy the `FlutterEngine` here.
+        (applicationContext as MyApplication).destroyFlutterEngine()
+
+        stopForegroundService()
+    }
+
+    override fun onBind(intent: Intent): IBinder? {
+        return binder
+    }
+
+    private fun createNotificationChannel(
+        context: Context,
+        channelId: String,
+        name: String,
+        des: String
+    ) {
+        val notificationManager =
+            ContextCompat.getSystemService(
+                context,
+                NotificationManager::class.java
+            ) as NotificationManager
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            if (notificationManager.getNotificationChannel(channelId) == null) {
+                val notificationChannel = NotificationChannel(
+                    channelId,
+                    name,
+                    NotificationManager.IMPORTANCE_DEFAULT
+                )
+                notificationChannel.setSound(null, null)
+                notificationChannel.enableLights(false)
+                notificationChannel.enableVibration(false)
+                notificationChannel.description = des
+                notificationManager.createNotificationChannel(notificationChannel)
+            }
+        }
+    }
+
+    private fun startForegroundService() {
+        createNotificationChannel(
+            applicationContext,
+            "MyChannelId",
+            "agora_rtc_engine_example",
+            "agora_rtc_engine_example running"
+        )
+
+        val notificationBuilder =
+            NotificationCompat
+                .Builder(this, "MyChannelId")
+                .setSmallIcon(R.mipmap.ic_launcher)
+                .setContentTitle("agora_rtc_engine_example")
+                .setContentText("agora_rtc_engine_example running")
+                .setWhen(System.currentTimeMillis())
+                .setPriority(NotificationCompat.PRIORITY_LOW)
+                .setContentIntent(getContentIntent())
+                .setShowWhen(false)
+
+        startForeground(NOTIFICATION_ID_DAEMON_SERVICE, notificationBuilder.build())
+    }
+
+    private fun getContentIntent(): PendingIntent? {
+        val intent = Intent(this, MainActivity::class.java).apply {
+            action = "NOTIFICATION_OPEN"
+        }
+        return PendingIntent.getActivity(
+            this,
+            0,
+            intent,
+            PendingIntent.FLAG_IMMUTABLE
+        )
+    }
+
+    private fun stopForegroundService() {
+        stopForeground(true)
+        stopSelf()
+    }
+
+    companion object {
+        const val ACTION_START_FOREGROUND_SERVICE = "ACTION_START_FOREGROUND_SERVICE"
+        private const val ACTION_STOP_FOREGROUND_SERVICE = "ACTION_STOP_FOREGROUND_SERVICE"
+
+        const val NOTIFICATION_ID_DAEMON_SERVICE = 123
+
+        private var isServiceRunning = false
+
+        fun startDaemonService(context: Context) {
+            if (isServiceRunning) {
+                return
+            }
+            try {
+                val intent = Intent(context, ExampleService::class.java)
+                intent.action = ACTION_START_FOREGROUND_SERVICE
+
+
+                val bundle = Bundle()
+                intent.putExtras(bundle)
+
+                // Crash: startForegroundService must call start startForeground
+                // This crash usually happens when background global configuration changes(like: Debug DisplayCut configuration changes)
+                context.startService(intent)
+                isServiceRunning = true
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+
+        fun stopDaemonService(context: Context) {
+            if (!isServiceRunning) {
+                return
+            }
+            try {
+                val intent = Intent(context, ExampleService::class.java)
+                intent.action = ACTION_STOP_FOREGROUND_SERVICE
+
+                // Crash: startForegroundService must call start startForeground
+                // This crash usually happens when background global configuration changes(like: Debug DisplayCut configuration changes)
+                context.startService(intent)
+                isServiceRunning = false
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+    }
+}

example/android/app/src/main/kotlin/io/agora/agora_rtc_flutter_example/MainActivity.kt

@@ -1,6 +1,41 @@
 package io.agora.agora_rtc_ng_example
 
+import android.content.Context
 import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodChannel
 
 class MainActivity: FlutterActivity() {
+    private lateinit var methodChannel: MethodChannel
+
+    override fun provideFlutterEngine(context: Context): FlutterEngine? {
+        return (context.applicationContext as MyApplication).getFlutterEngine()
+    }
+
+    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+        super.configureFlutterEngine(flutterEngine)
+
+        methodChannel = MethodChannel(flutterEngine.dartExecutor, "agora_rtc_ng_example/foreground_service")
+        methodChannel.setMethodCallHandler { call, result ->
+            when (call.method) {
+                "start_foreground_service" -> {
+                    ExampleService.startDaemonService(MainActivity@this.applicationContext)
+                    result.success(true)
+                }
+                "stop_foreground_service" -> {
+                    ExampleService.stopDaemonService(MainActivity@this.applicationContext)
+                    result.success(true)
+                }
+                else -> {
+                    result.notImplemented()
+                }
+            }
+        }
+    }
+
+    override fun detachFromFlutterEngine() {
+        super.detachFromFlutterEngine()
+
+        methodChannel.setMethodCallHandler(null)
+    }
 }

example/android/app/src/main/kotlin/io/agora/agora_rtc_flutter_example/MyApplication.kt

@@ -0,0 +1,17 @@
+package io.agora.agora_rtc_ng_example
+
+import io.flutter.app.FlutterApplication
+import io.flutter.embedding.engine.FlutterEngine
+
+class MyApplication : FlutterApplication() {
+    private var flutterEngine: FlutterEngine? = null
+
+    fun getFlutterEngine(): FlutterEngine {
+        return flutterEngine ?: FlutterEngine(this).also { flutterEngine = it }
+    }
+
+    fun destroyFlutterEngine() {
+        flutterEngine?.destroy()
+        flutterEngine = null
+    }
+}

example/android/build.gradle

@@ -27,6 +27,6 @@ subprojects {
     project.evaluationDependsOn(':app')
 }
 
-task clean(type: Delete) {
+tasks.register("clean", Delete) {
     delete rootProject.buildDir
 }

example/lib/components/android_foreground_service_widget.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class AndroidForegroundServiceWidget extends StatefulWidget {
+  const AndroidForegroundServiceWidget({Key? key, required this.child}) : super(key: key);
+
+  final Widget child;
+
+  @override
+  State<AndroidForegroundServiceWidget> createState() => _AndroidForegroundServiceWidgetState();
+}
+
+class _AndroidForegroundServiceWidgetState extends State<AndroidForegroundServiceWidget> {
+
+  final MethodChannel _channel = const MethodChannel('agora_rtc_ng_example/foreground_service');
+
+  @override
+  void initState() {
+    super.initState();
+
+    _channel.invokeMethod('start_foreground_service');
+  }
+
+  @override
+  void dispose() {
+    _channel.invokeMethod('stop_foreground_service');
+    super.dispose();
+  }
+
+
+  @override
+  Widget build(BuildContext context) {
+    return widget.child;
+  }
+}

example/lib/main.dart

@@ -1,3 +1,6 @@
+import 'dart:io';
+
+import 'package:agora_rtc_engine_example/components/android_foreground_service_widget.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:permission_handler/permission_handler.dart';
@@ -87,19 +90,24 @@ class _MyAppState extends State<MyApp> {
                         )
                       : ListTile(
                           onTap: () {
-                            Navigator.push(
-                                context,
-                                MaterialPageRoute(
-                                    builder: (context) => Scaffold(
-                                          appBar: AppBar(
-                                            title: Text(
-                                                _data[index]['name'] as String),
-                                            // ignore: prefer_const_literals_to_create_immutables
-                                            actions: [const LogActionWidget()],
-                                          ),
-                                          body:
-                                              _data[index]['widget'] as Widget?,
-                                        )));
+                            Navigator.push(context,
+                                MaterialPageRoute(builder: (context) {
+                              Widget widget = Scaffold(
+                                appBar: AppBar(
+                                  title: Text(_data[index]['name'] as String),
+                                  // ignore: prefer_const_literals_to_create_immutables
+                                  actions: [const LogActionWidget()],
+                                ),
+                                body: _data[index]['widget'] as Widget?,
+                              );
+
+                              if (Platform.isAndroid) {
+                                widget = AndroidForegroundServiceWidget(
+                                    child: widget);
+                              }
+
+                              return widget;
+                            }));
                           },
                           title: Text(
                             _data[index]['name'] as String,