Migrate to null safety

example/android/app/build.gradle

@@ -22,20 +22,21 @@ if (flutterVersionName == null) {
 }
 
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 30
 
-    lintOptions {
-        disable 'InvalidPackage'
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
     }
 
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId "com.rohansohonee.equalizer_example"
+        applicationId "com.rohansohonee.example"
         minSdkVersion 16
-        targetSdkVersion 28
+        targetSdkVersion 30
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
     }
@@ -52,3 +53,7 @@ android {
 flutter {
     source '../..'
 }
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}

example/android/app/src/debug/AndroidManifest.xml

@@ -1,5 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.rohansohonee.equalizer_example">
+    package="com.rohansohonee.example">
     <!-- Flutter needs it to communicate with the running application
          to allow setting breakpoints, to provide hot reload, etc.
     -->

example/android/app/src/main/AndroidManifest.xml

@@ -1,41 +1,37 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.rohansohonee.equalizer_example">
-
+    package="com.rohansohonee.example">
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
-    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
-         calls FlutterMain.startInitialization(this); in its onCreate method.
-         In most cases you can leave this as-is, but you if you want to provide
-         additional functionality it is fine to subclass or reimplement
-         FlutterApplication and put your custom class here. -->
-    <application
-        android:name="io.flutter.app.FlutterApplication"
-        android:icon="@mipmap/ic_launcher"
-        android:label="equalizer_example">
+
+   <application
+        android:label="example"
+        android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"
-            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
-            android:hardwareAccelerated="true"
             android:launchMode="singleTop"
             android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
             android:windowSoftInputMode="adjustResize">
             <!-- Specifies an Android theme to apply to this Activity as soon as
                  the Android process has started. This theme is visible to the user
                  while the Flutter UI initializes. After that, this theme continues
                  to determine the Window background behind the Flutter UI. -->
             <meta-data
-                android:name="io.flutter.embedding.android.NormalTheme"
-                android:resource="@style/NormalTheme" />
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
             <!-- Displays an Android View that continues showing the launch screen
                  Drawable until Flutter paints its first frame, then this splash
                  screen fades out. A splash screen is useful to avoid any visual
                  gap between the end of Android's launch screen and the painting of
                  Flutter's first frame. -->
             <meta-data
-                android:name="io.flutter.embedding.android.SplashScreenDrawable"
-                android:resource="@drawable/launch_background" />
+              android:name="io.flutter.embedding.android.SplashScreenDrawable"
+              android:resource="@drawable/launch_background"
+              />
             <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
         <!-- Don't delete the meta-data below.

example/android/app/src/main/kotlin/com/rohansohonee/example/MainActivity.kt

@@ -0,0 +1,6 @@
+package com.rohansohonee.example
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity: FlutterActivity() {
+}

example/android/app/src/main/res/drawable-v21/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="?android:colorBackground" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

example/android/app/src/main/res/values-night/styles.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is on -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             Flutter draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+         
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
+</resources>

example/android/app/src/main/res/values/styles.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <!-- Theme applied to the Android Window while the process is starting -->
-    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
         <!-- Show a splash screen on the activity. Automatically removed when
              Flutter draws its first frame -->
         <item name="android:windowBackground">@drawable/launch_background</item>
@@ -12,7 +12,7 @@
          running.
 
          This Theme is only used starting with V2 of Flutter's Android embedding. -->
-    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
-        <item name="android:windowBackground">@android:color/white</item>
+    <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
     </style>
 </resources>

example/android/app/src/profile/AndroidManifest.xml

@@ -1,5 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.rohansohonee.equalizer_example">
+    package="com.rohansohonee.example">
     <!-- Flutter needs it to communicate with the running application
          to allow setting breakpoints, to provide hot reload, etc.
     -->

example/android/build.gradle

@@ -1,11 +1,13 @@
 buildscript {
+    ext.kotlin_version = '1.3.50'
     repositories {
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:4.1.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
 

example/android/gradle.properties

@@ -1,4 +1,3 @@
 org.gradle.jvmargs=-Xmx1536M
-android.enableR8=true
 android.useAndroidX=true
 android.enableJetifier=true

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip

example/ios/Runner/AppDelegate.swift

@@ -0,0 +1,13 @@
+import UIKit
+import Flutter
+
+@UIApplicationMain
+@objc class AppDelegate: FlutterAppDelegate {
+  override func application(
+    _ application: UIApplication,
+    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+  ) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+  }
+}

example/ios/Runner/Runner-Bridging-Header.h

@@ -0,0 +1 @@
+#import "GeneratedPluginRegistrant.h"

example/lib/main.dart

@@ -1,9 +1,9 @@
 import 'dart:async';
-
 import 'package:equalizer/equalizer.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_xlider/flutter_xlider.dart';
+// import 'package:flutter_xlider/flutter_xlider.dart';
 
 void main() => runApp(MyApp());
 
@@ -74,7 +74,7 @@ class _MyAppState extends State<MyApp> {
                 },
               ),
             ),
-            FutureBuilder<List<int>>(
+            FutureBuilder<List<int>?>(
               future: Equalizer.getBandLevelRange(),
               builder: (context, snapshot) {
                 return snapshot.connectionState == ConnectionState.done
@@ -93,38 +93,38 @@ class CustomEQ extends StatefulWidget {
   const CustomEQ(this.enabled, this.bandLevelRange);
 
   final bool enabled;
-  final List<int> bandLevelRange;
+  final List<int>? bandLevelRange;
 
   @override
   _CustomEQState createState() => _CustomEQState();
 }
 
 class _CustomEQState extends State<CustomEQ> {
-  double min, max;
-  String _selectedValue;
-  Future<List<String>> fetchPresets;
+  double? min, max;
+  String? _selectedValue;
+  Future<List<String>?>? fetchPresets;
 
   @override
   void initState() {
     super.initState();
-    min = widget.bandLevelRange[0].toDouble();
-    max = widget.bandLevelRange[1].toDouble();
+    min = widget.bandLevelRange![0].toDouble();
+    max = widget.bandLevelRange![1].toDouble();
     fetchPresets = Equalizer.getPresetNames();
   }
 
   @override
   Widget build(BuildContext context) {
     int bandId = 0;
 
-    return FutureBuilder<List<int>>(
+    return FutureBuilder<List<int>?>(
       future: Equalizer.getCenterBandFreqs(),
       builder: (context, snapshot) {
         return snapshot.connectionState == ConnectionState.done
             ? Column(
                 children: [
                   Row(
                     mainAxisAlignment: MainAxisAlignment.center,
-                    children: snapshot.data
+                    children: snapshot.data!
                         .map((freq) => _buildSliderBand(freq, bandId++))
                         .toList(),
                   ),
@@ -145,7 +145,7 @@ class _CustomEQState extends State<CustomEQ> {
       children: [
         SizedBox(
           height: 250.0,
-          child: FutureBuilder<int>(
+          child: FutureBuilder<int?>(
             future: Equalizer.getBandLevel(bandId),
             builder: (context, snapshot) {
               return FlutterSlider(
@@ -154,7 +154,7 @@ class _CustomEQState extends State<CustomEQ> {
                 rtl: true,
                 min: min,
                 max: max,
-                values: [snapshot.hasData ? snapshot.data.toDouble() : 0],
+                values: [snapshot.hasData ? snapshot.data!.toDouble() : 0],
                 onDragCompleted: (handlerIndex, lowerValue, upperValue) {
                   Equalizer.setBandLevel(bandId, lowerValue.toInt());
                 },
@@ -168,11 +168,11 @@ class _CustomEQState extends State<CustomEQ> {
   }
 
   Widget _buildPresets() {
-    return FutureBuilder<List<String>>(
+    return FutureBuilder<List<String>?>(
       future: fetchPresets,
       builder: (context, snapshot) {
         if (snapshot.hasData) {
-          final presets = snapshot.data;
+          final presets = snapshot.data!;
           if (presets.isEmpty) return Text('No presets available!');
           return DropdownButtonFormField(
             decoration: InputDecoration(
@@ -181,8 +181,8 @@ class _CustomEQState extends State<CustomEQ> {
             ),
             value: _selectedValue,
             onChanged: widget.enabled
-                ? (String value) {
-                    Equalizer.setPreset(value);
+                ? (String? value) {
+                    Equalizer.setPreset(value!);
                     setState(() {
                       _selectedValue = value;
                     });
@@ -196,7 +196,7 @@ class _CustomEQState extends State<CustomEQ> {
             }).toList(),
           );
         } else if (snapshot.hasError)
-          return Text(snapshot.error);
+          return Text(snapshot.error as String);
         else
           return CircularProgressIndicator();
       },

example/pubspec.yaml

@@ -6,7 +6,7 @@ description: Demonstrates how to use the equalizer plugin.
 publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
@@ -22,8 +22,10 @@ dependencies:
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^0.1.3
-  flutter_xlider: ^3.4.0
+  cupertino_icons: ^1.0.2
+  # flutter_xlider: ^3.4.0
+  flutter_xlider: 
+    path: ../../flutter_xlider/
 
 dev_dependencies:
   flutter_test:

example/test/widget_test.dart

@@ -19,7 +19,7 @@ void main() {
     expect(
       find.byWidgetPredicate(
         (Widget widget) => widget is Text &&
-                           widget.data.startsWith('Running on:'),
+                           widget.data!.startsWith('Running on:'),
       ),
       findsOneWidget,
     );