made it null safety

example/.flutter-plugins-dependencies

@@ -0,0 +1 @@
+{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"thumbnails","path":"/Users/Macky/Downloads/Flutter_Thumbnails/","dependencies":[]}],"android":[{"name":"thumbnails","path":"/Users/Macky/Downloads/Flutter_Thumbnails/","dependencies":[]}],"macos":[],"linux":[],"windows":[],"web":[]},"dependencyGraph":[{"name":"thumbnails","dependencies":[]}],"date_created":"2021-09-25 00:21:14.941774","version":"2.2.3"}

example/ios/Flutter/Debug.xcconfig

@@ -1 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"

example/ios/Flutter/Release.xcconfig

@@ -1 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"

example/ios/Flutter/flutter_export_environment.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+# This is a generated file; do not edit or check into version control.
+export "FLUTTER_ROOT=/Users/Macky/Macky/applications/flutter"
+export "FLUTTER_APPLICATION_PATH=/Users/Macky/Downloads/Flutter_Thumbnails/example"
+export "COCOAPODS_PARALLEL_CODE_SIGN=true"
+export "FLUTTER_TARGET=lib/main.dart"
+export "FLUTTER_BUILD_DIR=build"
+export "SYMROOT=${SOURCE_ROOT}/../build/ios"
+export "FLUTTER_BUILD_NAME=1.0.0"
+export "FLUTTER_BUILD_NUMBER=1"
+export "DART_OBFUSCATION=false"
+export "TRACK_WIDGET_CREATION=false"
+export "TREE_SHAKE_ICONS=false"
+export "PACKAGE_CONFIG=.packages"

example/ios/Podfile

@@ -0,0 +1,38 @@
+# Uncomment this line to define a global platform for your project
+# platform :ios, '9.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_ios_podfile_setup
+
+target 'Runner' do
+  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_ios_build_settings(target)
+  end
+end

example/lib/main.dart

@@ -12,10 +12,11 @@ class _MyAppState extends State<MyApp> {
   // Fetch thumbnail and store in a specified output folder
   void _toUserFolder() async {
     String thumb = await Thumbnails.getThumbnail(
-        thumbnailFolder: '/storage/emulated/0/Videos/Thumbnails',
-        videoFile: '/storage/emulated/0/Videos/Testvideo.mp4',
-        imageType: ThumbFormat.PNG,
-        quality: 30);
+      thumbnailFolder: '/storage/emulated/0/Videos/Thumbnails',
+      videoFile: '/storage/emulated/0/Videos/Testvideo.mp4',
+      imageType: ThumbFormat.PNG,
+      quality: 30,
+    );
     print('path to File: $thumb');
   }
 
@@ -38,9 +39,9 @@ class _MyAppState extends State<MyApp> {
         body: new Center(
           child: Column(
             children: <Widget>[
-              RaisedButton(
+              ElevatedButton(
                   onPressed: _toUserFolder, child: Text('To Specified Folder')),
-              RaisedButton(
+              ElevatedButton(
                   onPressed: _noFolder, child: Text('No Folder Specified')),
             ],
           ),

lib/thumbnails.dart

@@ -1,5 +1,4 @@
 import 'dart:async';
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:thumbnails/validators.dart';
 
@@ -8,18 +7,19 @@ enum ThumbFormat { PNG, JPEG, WEBP }
 class Thumbnails {
   static const MethodChannel _channel = const MethodChannel('thumbnails');
 
-  static Future<String> getThumbnail(
-      {@required String videoFile,
-      String thumbnailFolder,
-      ThumbFormat imageType,
-      int quality}) async {
+  static Future<String?> getThumbnail(
+      {required String videoFile,
+      String? thumbnailFolder,
+      ThumbFormat? imageType,
+      required int? quality}) async {
     var utilMap = <String, dynamic>{
       'videoFilePath': videoFile,
       'thumbFilePath': thumbnailFolder,
       'thumbnailFormat': validateType(imageType),
       'thumbnailQuality': validateQuality(quality)
     };
-    String thumbnailPath = await _channel.invokeMethod('getThumbnail', utilMap);
+    String? thumbnailPath =
+        await _channel.invokeMethod('getThumbnail', utilMap);
     return thumbnailPath;
   }
 }

lib/validators.dart

@@ -3,23 +3,20 @@ import 'package:thumbnails/thumbnails.dart';
 const DEFAULT_THUMB_QUALITY = 50;
 const DEFAULT_IMAGE_TYPE = ThumbFormat.JPEG;
 
-int validateQuality(int choice) {
-  if (choice < 10 || choice > 100 || choice == null)
+int validateQuality(int? choice) {
+  if (choice == null || choice < 10 || choice > 100)
     return DEFAULT_THUMB_QUALITY;
   return choice;
 }
 
-int validateType(ThumbFormat type) {
+int validateType(ThumbFormat? type) {
   if (type == null) return 1;
   switch (type) {
     case ThumbFormat.JPEG:
       return 1;
-      break;
     case ThumbFormat.PNG:
       return 2;
-      break;
     case ThumbFormat.WEBP:
       return 3;
   }
-  return 1;
 }

pubspec.yaml

@@ -5,7 +5,7 @@ author: AsapJay <asapjayfroshcr9@gmail.com>
 homepage: https://github.com/asapJ/Flutter_Thumbnails
 
 environment:
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
@@ -19,6 +19,8 @@ flutter:
   plugin:
     androidPackage: com.asapjay.thumbnails
     pluginClass: ThumbnailsPlugin
+dev_dependencies: 
+  test: ^1.17.12
 
   # To add assets to your plugin package, add an assets section, like this:
   # assets: