From 1f3b7b5ba3d850ee043f0e6570aa5e0253975339 Mon Sep 17 00:00:00 2001
From: Eiichiro Adachi <addie@initig.com>
Date: Mon, 27 Apr 2020 19:49:04 +0900
Subject: [PATCH 1/2] Handle updateProgress for Android.

---
 lib/src/downloader.dart | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/src/downloader.dart b/lib/src/downloader.dart
index 267cd295..0fa8e62d 100644
--- a/lib/src/downloader.dart
+++ b/lib/src/downloader.dart
@@ -386,6 +386,22 @@ class FlutterDownloader {
   static registerCallback(DownloadCallback callback) {
     assert(_initialized, 'FlutterDownloader.initialize() must be called first');
 
+    if (callback != null) {
+      // remove previous setting
+      _channel.setMethodCallHandler(null);
+      _channel.setMethodCallHandler((MethodCall call) async {
+        if (call.method == 'updateProgress') {
+          String id = call.arguments['task_id'];
+          int status = call.arguments['status'];
+          int process = call.arguments['progress'];
+          callback(id, DownloadTaskStatus(status), process);
+        }
+        return null;
+      });
+    } else {
+      _channel.setMethodCallHandler(null);
+    }
+
     final callbackHandle = PluginUtilities.getCallbackHandle(callback);
     assert(callbackHandle != null,
         'callback must be a top-level or a static function');

From e99d85ddf50d8f5ffc920a6ce47953d48846fd49 Mon Sep 17 00:00:00 2001
From: Eiichiro Adachi <addie@initig.com>
Date: Tue, 7 Sep 2021 13:37:39 +0900
Subject: [PATCH 2/2] update README and example

---
 README.md             | 2 ++
 example/lib/main.dart | 1 +
 2 files changed, 3 insertions(+)

diff --git a/README.md b/README.md
index ed4ed365..43f4cc31 100644
--- a/README.md
+++ b/README.md
@@ -273,6 +273,7 @@ void initState() {
 
 @override
 void dispose() {
+  FlutterDownloader.registerCallback(null);
 	IsolateNameServer.removePortNameMapping('downloader_send_port');
 	super.dispose();
 }
@@ -284,6 +285,7 @@ static void downloadCallback(String id, DownloadTaskStatus status, int progress)
 
 ````
 
+- Note: set `callback` as `null` to remove listener. You should clean up callback to prevent from leaking references.
 
 #### Load all tasks:
 
diff --git a/example/lib/main.dart b/example/lib/main.dart
index d6b32106..a8cc011d 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -129,6 +129,7 @@ class _MyHomePageState extends State<MyHomePage> {
 
   @override
   void dispose() {
+    FlutterDownloader.registerCallback(null);
     _unbindBackgroundIsolate();
     super.dispose();
   }