Fix npe

android/app/build.gradle

@@ -72,5 +72,5 @@ dependencies {
  testImplementation 'junit:junit:4.12'
  androidTestImplementation 'androidx.test:runner:1.1.0-alpha4'
  androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha4'
- compile 'com.android.support:multidex:1.0.3'
+ implementation 'com.android.support:multidex:1.0.3'
 }

android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
  }
 
  dependencies {
- classpath 'com.android.tools.build:gradle:4.2.0'
+ classpath 'com.android.tools.build:gradle:7.3.1'
  }
 }
 

lib/screens/home.dart

@@ -122,7 +122,7 @@ class HomeState extends State<Home> {
  return null;
  }
 
- void _handleSubmitted(BuildContext context, Subject subject, String title,
+ void _handleSubmitted(BuildContext context, Subject? subject, String title,
  String description) async {
  updateModel(
  context,

lib/screens/subject_details.dart

@@ -158,10 +158,10 @@ class SubjectDetailsState extends State<SubjectDetails> {
  return null;
  }
 
- void _handleEdit(BuildContext context, Subject subject, String title,
+ void _handleEdit(BuildContext context, Subject? subject, String title,
  String description) async {
  updateModel(context, (model) {
- Subject s = model.subjects[model.subjects.indexOf(subject)];
+ Subject s = model.subjects[model.subjects.indexOf(subject!)];
  if (title.isNotEmpty) {
  s.title = title;
  }
@@ -180,11 +180,11 @@ class SubjectDetailsState extends State<SubjectDetails> {
  return null;
  }
 
- void _handleSubmitted(BuildContext context, Subject subject, String title,
+ void _handleSubmitted(BuildContext context, Subject? subject, String title,
  String description) async {
  updateModel(
  context,
- (model) => model.addTopic(subject,
+ (model) => model.addTopic(subject!,
  new Topic(title: title, description: description, indexes: [])));
  createDirs(title);
  Navigator.pop(context);

lib/screens/topic_details.dart

@@ -230,10 +230,10 @@ class TopicDetailsState extends State<TopicDetails> {
  return null;
  }
 
- void _handleEdit(BuildContext context, Subject subject, String title,
+ void _handleEdit(BuildContext context, Subject? subject, String title,
  String description) async {
  updateModel(context, (model) {
- Subject s = model.subjects[model.subjects.indexOf(subject)];
+ Subject s = model.subjects[model.subjects.indexOf(subject!)];
  Topic t = s.topics[s.topics.indexOf(widget.topic)];
  if (title.isNotEmpty) {
  String oldTitle = t.title;

lib/widgets/add_topic_form.dart

@@ -5,7 +5,7 @@ import 'package:study_snap/models/subject.dart';
 typedef String? ValidateCallback(
  BuildContext context, Subject? subject, String? value);
 typedef void SubmitCallback(
- BuildContext context, Subject subject, String title, String description);
+ BuildContext context, Subject? subject, String title, String description);
 
 class AddTopicForm extends StatefulWidget {
  final Subject? subject;
@@ -80,7 +80,7 @@ class AddTopicFormState extends State<AddTopicForm> {
  if (form != null && form.validate()) {
  form.save();
  widget.handleSubmitted(
- context, widget.subject!, title, description);
+ context, widget.subject, title, description);
  }
  },
  ),

pubspec.yaml

@@ -11,7 +11,7 @@ description: Flutter app for managing study materials in form of photos.
 # In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
-version: 1.1.1+5
+version: 1.1.1+6
 
 environment:
  sdk: ">=2.12.0 <3.0.0"