APK Service is ready

lib/services/apk_service.dart

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+import 'dart:async';
+import 'dart:io';
+import 'dart:isolate';
+import 'dart:ui';
+
+import 'package:flutter/material.dart';
+import 'package:file_picker/file_picker.dart';
+import 'package:install_plugin_v2/install_plugin_v2.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:permission_handler/permission_handler.dart';
+import 'package:flutter_downloader/flutter_downloader.dart';
+import 'package:app_installer/app_installer.dart';
+import 'package:flutter_fgbg/flutter_fgbg.dart';
+import 'package:flutter_local_notifications/flutter_local_notifications.dart';
+
+class APKService {
+  APKService() {
+    initializeDownloader();
+  }
+
+  // Notifications plugin for downloads
+  FlutterLocalNotificationsPlugin downloaderNotifications =
+      FlutterLocalNotificationsPlugin();
+
+  // Port for FlutterDownloader background/foreground communication
+  ReceivePort _port = ReceivePort();
+
+  // Variables to keep track of the app foreground status (installs can't run in the background)
+  bool isForeground = true;
+  StreamSubscription<FGBGType>? foregroundSubscription;
+
+  // Setup the FlutterDownloader plugin (call in main())
+  Future<void> initializeDownloader() async {
+    // Make sure FlutterDownloader can be used
+    await FlutterDownloader.initialize();
+    // Set up the status update callback for FlutterDownloader
+    FlutterDownloader.registerCallback(downloadCallbackBackground);
+    // The actual callback is in the background isolate
+    // So setup a port to pass the data to a foreground callback
+    IsolateNameServer.registerPortWithName(
+        _port.sendPort, 'downloader_send_port');
+    _port.listen((dynamic data) {
+      String id = data[0];
+      DownloadTaskStatus status = data[1];
+      int progress = data[2];
+      downloadCallbackForeground(id, status, progress);
+    });
+    // Initialize the notifications service
+    await downloaderNotifications.initialize(const InitializationSettings(
+        android: AndroidInitializationSettings('ic_launcher')));
+    // Subscribe to changes in the app foreground status
+    foregroundSubscription = FGBGEvents.stream.listen((event) async {
+      isForeground = event == FGBGType.foreground;
+    });
+  }
+
+  // Clean up after initializeDownloader() (call in dispose())
+  void dispose() {
+    IsolateNameServer.removePortNameMapping('downloader_send_port');
+    foregroundSubscription?.cancel();
+  }
+
+  // Callback that receives FlutterDownloader status and forwards to a foreground function
+  @pragma('vm:entry-point')
+  static void downloadCallbackBackground(
+      String id, DownloadTaskStatus status, int progress) {
+    final SendPort? send =
+        IsolateNameServer.lookupPortByName('downloader_send_port');
+    send!.send([id, status, progress]);
+  }
+
+  // Foreground function to act on FlutterDownloader status updates (install downloaded APK)
+  void downloadCallbackForeground(
+      String id, DownloadTaskStatus status, int progress) async {
+    if (status == DownloadTaskStatus.complete) {
+      // Wait for app to come to the foreground if not already, and notify the user
+      while (!isForeground) {
+        await downloaderNotifications.show(
+            1,
+            'Complete App Installation',
+            'Obtainium must be open to install Apps',
+            const NotificationDetails(
+                android: AndroidNotificationDetails(
+                    'COMPLETE_INSTALL', 'Complete App Installation',
+                    channelDescription:
+                        'Ask the user to return to Obtanium to finish installing an App',
+                    importance: Importance.max,
+                    priority: Priority.max,
+                    groupKey: 'dev.imranr.obtainium.COMPLETE_INSTALL')));
+        if (await FGBGEvents.stream.first == FGBGType.foreground) {
+          break;
+        }
+      }
+      FlutterDownloader.open(taskId: id);
+      downloaderNotifications.cancel(1);
+    }
+  }
+
+  // Given a URL (assumed valid), initiate an APK download (will trigger install callback when complete)
+  void downloadAndInstallAPK(String url, String appId) async {
+    var apkDir = Directory(
+        "${(await getExternalStorageDirectory())?.path as String}/$appId");
+    if (apkDir.existsSync()) apkDir.deleteSync(recursive: true);
+    apkDir.createSync();
+    await FlutterDownloader.enqueue(
+      url: url,
+      savedDir: apkDir.path,
+      showNotification: true,
+      openFileFromNotification: false,
+    );
+  }
+}