From 0b1a41f3bd50443d3fb1ab5e2c93c27bccdc1412 Mon Sep 17 00:00:00 2001
From: Vishesh Handa <me@vhanda.in>
Date: Sat, 7 Dec 2019 16:21:28 +0100
Subject: [PATCH] FolderListing: Use Provider to fetch the NotesFolder

This is our first use case of trying to use 'Provider' for state
management. Right now, we're doing state management quite horribly as
all the widgets are rebuilt whenever the state of the app changes.

With this, we can now start to refactor and only rebuild the widgets
whose data has changed.

There we many many different state management solutions to choose from,
I've settled on Provider, as it seems like the simplest to integrate
into the code base. Bloc/Redux seemed like they would add too much
complexity for me.
---
 lib/app.dart                    |  6 +++++-
 lib/screens/folder_listing.dart | 10 +++++-----
 pubspec.lock                    |  7 +++++++
 pubspec.yaml                    |  1 +
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/lib/app.dart b/lib/app.dart
index 448f3d08..ccabb61e 100644
--- a/lib/app.dart
+++ b/lib/app.dart
@@ -5,6 +5,7 @@ import 'package:fimber/fimber.dart';
 import 'package:firebase_analytics/firebase_analytics.dart';
 import 'package:firebase_analytics/observer.dart';
 import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
 
 import 'package:gitjournal/apis/git.dart';
 import 'package:gitjournal/settings.dart';
@@ -46,7 +47,10 @@ class JournalApp extends StatelessWidget {
 
     runApp(StateContainer(
       appState: appState,
-      child: JournalApp(),
+      child: ChangeNotifierProvider(
+        child: JournalApp(),
+        create: (_) => appState.notesFolder,
+      ),
     ));
   }
 
diff --git a/lib/screens/folder_listing.dart b/lib/screens/folder_listing.dart
index 710b102c..c883c455 100644
--- a/lib/screens/folder_listing.dart
+++ b/lib/screens/folder_listing.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
 
 import 'package:gitjournal/widgets/app_bar_menu_button.dart';
 import 'package:gitjournal/widgets/app_drawer.dart';
@@ -18,11 +19,10 @@ class _FolderListingScreenState extends State<FolderListingScreen> {
 
   @override
   Widget build(BuildContext context) {
-    final container = StateContainer.of(context);
-    final appState = container.appState;
+    final notesFolder = Provider.of<NotesFolder>(context);
 
     var treeView = FolderTreeView(
-      rootFolder: appState.notesFolder,
+      rootFolder: notesFolder,
       onFolderEntered: (NotesFolder folder) {
         var route = MaterialPageRoute(
           builder: (context) => JournalListingScreen(
@@ -99,9 +99,9 @@ class _CreateFolderButtonState extends State<CreateFolderButton> {
             await showDialog(context: context, builder: _buildAlert);
         if (folderName is String) {
           final container = StateContainer.of(context);
-          final appState = container.appState;
+          final notesFolder = Provider.of<NotesFolder>(context);
 
-          container.createFolder(appState.notesFolder, folderName);
+          container.createFolder(notesFolder, folderName);
         }
       },
       child: Icon(Icons.add),
diff --git a/pubspec.lock b/pubspec.lock
index edb7c903..44292a66 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -399,6 +399,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.0.11"
+  provider:
+    dependency: "direct main"
+    description:
+      name: provider
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.2.0"
   pub_semver:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index 116032ff..2ff1ad9e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -29,6 +29,7 @@ dependencies:
   flushbar: ^1.9.0
   flutter_staggered_grid_view: ^0.3.0
   page_transition: "^1.1.5"
+  provider: ^3.2.0
 
 dev_dependencies:
   flutter_launcher_icons: "^0.7.2"