Add new useRefreshable hook

lib/hooks/refreshable.dart

@@ -0,0 +1,37 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+import 'memo_future.dart';
+
+class Refreshable<T> {
+  const Refreshable({@required this.snapshot, @required this.refresh})
+      : assert(snapshot != null),
+        assert(refresh != null);
+
+  final AsyncSnapshot<T> snapshot;
+  final AsyncCallback refresh;
+}
+
+Refreshable<T> useRefreshable<T>(AsyncValueGetter<T> fetcher,
+    [List<Object> keys = const <dynamic>[]]) {
+  final newData = useState<T>(null);
+  final snapshot = useMemoFuture(() async {
+    newData.value = null;
+    return fetcher();
+  }, keys);
+
+  final outSnapshot = () {
+    if (newData.value != null) {
+      return AsyncSnapshot.withData(ConnectionState.done, newData.value);
+    }
+    return snapshot;
+  }();
+
+  return Refreshable(
+    snapshot: outSnapshot,
+    refresh: () async {
+      newData.value = await fetcher();
+    },
+  );
+}

lib/pages/communities_tab.dart

@@ -8,7 +8,7 @@ import 'package:fuzzy/fuzzy.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 
 import '../hooks/delayed_loading.dart';
-import '../hooks/memo_future.dart';
+import '../hooks/refreshable.dart';
 import '../hooks/stores.dart';
 import '../util/extensions/api.dart';
 import '../util/extensions/iterators.dart';
@@ -60,14 +60,11 @@ class CommunitiesTab extends HookWidget {
     }
 
     // TODO: rebuild when instances/accounts change
-    final instancesSnap = useMemoFuture(getInstances);
+    final instancesRefreshable = useRefreshable(getInstances);
-    final communitiesSnap = useMemoFuture(getCommunities);
+    final communitiesRefreshable = useRefreshable(getCommunities);
 
-    final updatedCommunities =
+    if (communitiesRefreshable.snapshot.hasError ||
-        useState<List<List<CommunityFollowerView>>>(null);
+        instancesRefreshable.snapshot.hasError) {
-    final updatedInstances = useState<List<SiteView>>(null);
-
-    if (communitiesSnap.hasError || instancesSnap.hasError) {
       return Scaffold(
         appBar: AppBar(),
         body: Center(
@@ -77,15 +74,16 @@ class CommunitiesTab extends HookWidget {
               Padding(
                 padding: const EdgeInsets.all(8),
                 child: Text(
-                  communitiesSnap.error?.toString() ??
+                  communitiesRefreshable.snapshot.error?.toString() ??
-                      instancesSnap.error?.toString(),
+                      instancesRefreshable.snapshot.error?.toString(),
                 ),
               )
             ],
           ),
         ),
       );
-    } else if (!communitiesSnap.hasData || !instancesSnap.hasData) {
+    } else if (!communitiesRefreshable.snapshot.hasData ||
+        !instancesRefreshable.snapshot.hasData) {
       return Scaffold(
         appBar: AppBar(),
         body: const Center(
@@ -97,11 +95,10 @@ class CommunitiesTab extends HookWidget {
     refresh() async {
       await HapticFeedback.mediumImpact();
       try {
-        final i = getInstances();
+        await Future.wait([
-        final c = getCommunities();
+          instancesRefreshable.refresh(),
-        await Future.wait([i, c]);
+          communitiesRefreshable.refresh(),
-        updatedInstances.value = await i;
+        ]);
-        updatedCommunities.value = await c;
         // ignore: avoid_catches_without_on_clauses
       } catch (e) {
         Scaffold.of(context)
@@ -109,8 +106,8 @@ class CommunitiesTab extends HookWidget {
       }
     }
 
-    final instances = updatedInstances.value ?? instancesSnap.data;
+    final instances = instancesRefreshable.snapshot.data;
-    final communities = updatedCommunities.value ?? communitiesSnap.data
+    final communities = communitiesRefreshable.snapshot.data
       ..forEach(
           (e) => e.sort((a, b) => a.communityName.compareTo(b.communityName)));
 
@@ -239,6 +236,7 @@ class CommunitiesTab extends HookWidget {
                             ],
                           ),
                           trailing: _CommunitySubscribeToggle(
+                            key: ValueKey(comm.communityId),
                             instanceHost: comm.instanceHost,
                             communityId: comm.communityId,
                           ),
@@ -258,9 +256,10 @@ class _CommunitySubscribeToggle extends HookWidget {
   final String instanceHost;
 
   const _CommunitySubscribeToggle(
-      {@required this.instanceHost, @required this.communityId})
+      {@required this.instanceHost, @required this.communityId, Key key})
       : assert(instanceHost != null),
-        assert(communityId != null);
+        assert(communityId != null),
+        super(key: key);
 
   @override
   Widget build(BuildContext context) {

lib/pages/full_post.dart

@@ -6,7 +6,7 @@ import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 
 import '../hooks/logged_in_action.dart';
-import '../hooks/memo_future.dart';
+import '../hooks/refreshable.dart';
 import '../hooks/stores.dart';
 import '../util/more_icon.dart';
 import '../widgets/comment_section.dart';
@@ -19,10 +19,8 @@ class FullPostPage extends HookWidget {
   final int id;
   final String instanceHost;
   final PostView post;
-  final GlobalKey<RefreshIndicatorState> _refreshIndicatorKey =
-      GlobalKey<RefreshIndicatorState>();
 
-  FullPostPage({@required this.id, @required this.instanceHost})
+  const FullPostPage({@required this.id, @required this.instanceHost})
       : assert(id != null),
         assert(instanceHost != null),
         post = null;
@@ -33,23 +31,22 @@ class FullPostPage extends HookWidget {
   @override
   Widget build(BuildContext context) {
     final accStore = useAccountsStore();
-    final fullPostSnap = useMemoFuture(() => LemmyApi(instanceHost)
+    final fullPostRefreshable = useRefreshable(() => LemmyApi(instanceHost)
         .v1
         .getPost(id: id, auth: accStore.defaultTokenFor(instanceHost)?.raw));
     final loggedInAction = useLoggedInAction(instanceHost);
     final newComments = useState(const <CommentView>[]);
-    final updatedPost = useState<FullPostView>(null);
-    // FALLBACK VIEW
 
-    if (!fullPostSnap.hasData && this.post == null) {
+    // FALLBACK VIEW
+    if (!fullPostRefreshable.snapshot.hasData && this.post == null) {
       return Scaffold(
         appBar: AppBar(),
         body: Center(
           child: Column(
             mainAxisAlignment: MainAxisAlignment.center,
             children: [
-              if (fullPostSnap.hasError)
+              if (fullPostRefreshable.snapshot.hasError)
-                Text(fullPostSnap.error.toString())
+                Text(fullPostRefreshable.snapshot.error.toString())
               else
                 const CircularProgressIndicator(),
             ],
@@ -60,10 +57,11 @@ class FullPostPage extends HookWidget {
 
     // VARIABLES
 
-    final post = updatedPost.value?.post ??
+    final post = fullPostRefreshable.snapshot.hasData
-        (fullPostSnap.hasData ? fullPostSnap.data.post : this.post);
+        ? fullPostRefreshable.snapshot.data.post
+        : this.post;
 
-    final fullPost = updatedPost.value ?? fullPostSnap.data;
+    final fullPost = fullPostRefreshable.snapshot.data;
 
     // FUNCTIONS
 
@@ -71,9 +69,7 @@ class FullPostPage extends HookWidget {
       await HapticFeedback.mediumImpact();
 
       try {
-        return await LemmyApi(instanceHost)
+        await fullPostRefreshable.refresh();
-            .v1
-            .getPost(id: id, auth: accStore.defaultTokenFor(instanceHost)?.raw);
         // ignore: avoid_catches_without_on_clauses
       } catch (e) {
         Scaffold.of(context).showSnackBar(SnackBar(
@@ -110,23 +106,22 @@ class FullPostPage extends HookWidget {
             child: const Icon(Icons.comment)),
         body: RefreshIndicator(
           onRefresh: refresh,
-          key: _refreshIndicatorKey,
           child: ListView(
             physics: const AlwaysScrollableScrollPhysics(),
             children: [
               Post(post, fullPost: true),
-              if (fullPostSnap.hasData)
+              if (fullPostRefreshable.snapshot.hasData)
                 CommentSection(
                     newComments.value.followedBy(fullPost.comments).toList(),
                     postCreatorId: fullPost.post.creatorId)
-              else if (fullPostSnap.hasError)
+              else if (fullPostRefreshable.snapshot.hasError)
                 Padding(
                   padding:
                       const EdgeInsets.symmetric(horizontal: 10, vertical: 30),
                   child: Column(
                     children: [
                       const Icon(Icons.error),
-                      Text('Error: ${fullPostSnap.error}')
+                      Text('Error: ${fullPostRefreshable.snapshot.error}')
                     ],
                   ),
                 )