fix: properly close app on back gesture (#1570)

app/assets/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.16.0 (unreleased)
+
+- fix(android): properly close app on back gesture (@Tienisto)
+
 ## 1.15.2 (2024-07-25)
 
 - feat: extract network scanning to separate threads, scanning should not cause UI lags anymore (@Tienisto)

app/lib/main.dart

@@ -1,3 +1,4 @@
+import 'package:common/isolate.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:localsend_app/gen/strings.g.dart';
@@ -38,8 +39,17 @@ class LocalSendApp extends StatelessWidget {
       child: WindowWatcher(
         child: LifeCycleWatcher(
           onChangedState: (AppLifecycleState state) {
-            if (state == AppLifecycleState.resumed) {
-              ref.redux(localIpProvider).dispatch(InitLocalIpAction());
+            switch (state) {
+              case AppLifecycleState.resumed:
+                ref.redux(localIpProvider).dispatch(InitLocalIpAction());
+                break;
+              case AppLifecycleState.detached:
+                // The main isolate is only exited when all child isolates are exited.
+                // https://github.com/localsend/localsend/issues/1568
+                ref.redux(parentIsolateProvider).dispatch(IsolateDisposeAction());
+                break;
+              default:
+                break;
             }
           },
           child: ShortcutWatcher(

common/lib/src/isolate/parent/parent_isolate_provider.dart

@@ -96,3 +96,13 @@ class IsolateSetupAction extends AsyncReduxAction<IsolateController, ParentIsola
     );
   }
 }
+
+class IsolateDisposeAction extends ReduxAction<IsolateController, ParentIsolateState> {
+  @override
+  ParentIsolateState reduce() {
+    state.httpScanDiscovery?.isolate.kill();
+    state.httpTargetDiscovery?.isolate.kill();
+    state.multicastDiscovery?.isolate.kill();
+    return state;
+  }
+}