chore: Update Android gradle config, resolve some linting issues (#67)

Followed this guide to update Android gradle config to new recommended settings:
https://docs.flutter.dev/release/breaking-changes/flutter-gradle-plugin-apply

Updated sdk version in example app's pubspec.

Fixed some linting issues after locally updating the flutter_lints package to 5.0.0,
most notably using super parameters. However, that change to use version 5.0.0 could
not be committed because we still support Dart 2.19, which is tied to flutter_lints 2.0.3.

example/android/app/build.gradle

@@ -1,3 +1,9 @@
+plugins {
+    id "com.android.application"
+    id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
+}
+
 def localProperties = new Properties()
 def localPropertiesFile = rootProject.file('local.properties')
 if (localPropertiesFile.exists()) {
@@ -6,11 +12,6 @@ if (localPropertiesFile.exists()) {
     }
 }
 
-def flutterRoot = localProperties.getProperty('flutter.sdk')
-if (flutterRoot == null) {
-    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
-}
-
 def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
 if (flutterVersionCode == null) {
     flutterVersionCode = '1'
@@ -21,10 +22,6 @@ if (flutterVersionName == null) {
     flutterVersionName = '1.0'
 }
 
-apply plugin: 'com.android.application'
-apply plugin: 'kotlin-android'
-apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
-
 android {
     compileSdkVersion flutter.compileSdkVersion
 
@@ -62,7 +59,3 @@ android {
 flutter {
     source '../..'
 }
-
-dependencies {
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
-}

example/android/build.gradle

@@ -1,16 +1,3 @@
-buildscript {
-    ext.kotlin_version = '1.6.10'
-    repositories {
-        google()
-        mavenCentral()
-    }
-
-    dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.0'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-    }
-}
-
 allprojects {
     repositories {
         google()

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-6.7-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.1-all.zip

example/android/settings.gradle

@@ -1,11 +1,25 @@
-include ':app'
+pluginManagement {
+    def flutterSdkPath = {
+        def properties = new Properties()
+        file("local.properties").withInputStream { properties.load(it) }
+        def flutterSdkPath = properties.getProperty("flutter.sdk")
+        assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+        return flutterSdkPath
+    }()
 
-def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
-def properties = new Properties()
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
 
-assert localPropertiesFile.exists()
-localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
 
-def flutterSdkPath = properties.getProperty("flutter.sdk")
-assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
-apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"
+plugins {
+    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
+    id "com.android.application" version "7.3.0" apply false
+    id "org.jetbrains.kotlin.android" version "1.7.10" apply false
+}
+
+include ":app"

example/lib/async_demo_page.dart

@@ -3,10 +3,10 @@ import 'package:flutter/material.dart';
 
 /// Simple example of how to use EasyImageViewer with a FutureBuilder
 class AsyncDemoPage extends StatefulWidget {
-  const AsyncDemoPage({Key? key}) : super(key: key);
+  const AsyncDemoPage({super.key});
 
   @override
-  _AsyncDemoPageState createState() => _AsyncDemoPageState();
+  State<AsyncDemoPage> createState() => _AsyncDemoPageState();
 }
 
 class _AsyncDemoPageState extends State<AsyncDemoPage> {

example/lib/main.dart

@@ -5,7 +5,7 @@ import 'package:flutter/material.dart';
 void main() => runApp(const MyApp());
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key? key}) : super(key: key);
+  const MyApp({super.key});
 
   @override
   Widget build(BuildContext context) {
@@ -25,12 +25,12 @@ class MyHomePage extends StatefulWidget {
   final String title;
 
   const MyHomePage({
-    Key? key,
+    super.key,
     required this.title,
-  }) : super(key: key);
+  });
 
   @override
-  _MyHomePageState createState() => _MyHomePageState();
+  State<MyHomePage> createState() => _MyHomePageState();
 }
 
 class _MyHomePageState extends State<MyHomePage> {

example/pubspec.yaml

@@ -18,7 +18,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.16.1 <3.0.0"
+  sdk: ">=2.19.0 <4.0.0"  # This implies at least Dart 2.19, which comes with Flutter 3.7.0
 
 # Dependencies specify other packages that your package needs in order to work.
 # To automatically upgrade your package dependencies to the latest versions

lib/easy_image_viewer.dart

@@ -1,6 +1,6 @@
 /// A library to easily display images in a full-screen dialog.
 /// It supports pinch & zoom, and paging through multiple images.
-library easy_image_viewer;
+library;
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';

lib/src/easy_image_view.dart

@@ -39,12 +39,12 @@ class EasyImageView extends StatefulWidget {
   /// The optional [doubleTapZoomable] boolean defaults to false and allows double tap to zoom.
   const EasyImageView.imageWidget(
     this.imageWidget, {
-    Key? key,
+    super.key,
     this.minScale = 1.0,
     this.maxScale = 5.0,
     this.doubleTapZoomable = false,
     this.onScaleChanged,
-  }) : super(key: key);
+  });
 
   @override
   State<EasyImageView> createState() => _EasyImageViewState();

lib/src/easy_image_view_pager.dart

@@ -27,13 +27,13 @@ class EasyImageViewPager extends StatefulWidget {
   /// and the [pageController] to control the initial image index to display.
   /// The optional [doubleTapZoomable] boolean defaults to false and allows double tap to zoom.
   const EasyImageViewPager({
-    Key? key,
+    super.key,
     required this.easyImageProvider,
     required this.pageController,
     this.doubleTapZoomable = false,
     this.onScaleChanged,
     this.infinitelyScrollable = false,
-  }) : super(key: key);
+  });
 
   @override
   State<EasyImageViewPager> createState() => _EasyImageViewPagerState();

lib/src/easy_image_viewer_dismissible_dialog.dart

@@ -22,7 +22,7 @@ class EasyImageViewerDismissibleDialog extends StatefulWidget {
 
   /// Refer to [showImageViewerPager] for the arguments
   const EasyImageViewerDismissibleDialog(this.imageProvider,
-      {Key? key,
+      {super.key,
       this.immersive = true,
       this.onPageChanged,
       this.onViewerDismissed,
@@ -31,8 +31,7 @@ class EasyImageViewerDismissibleDialog extends StatefulWidget {
       this.infinitelyScrollable = false,
       required this.backgroundColor,
       required this.closeButtonTooltip,
-      required this.closeButtonColor})
-      : super(key: key);
+      required this.closeButtonColor});
 
   @override
   State<EasyImageViewerDismissibleDialog> createState() =>