Applying Flutters app_plugin_loader Gradle plugin imperatively using the apply script method which is deprecated, will be removed in a future release

After Upgrading the Flutter version to 3.19.0 I am getting this warning when running the app:

You are applying Flutter's app_plugin_loader Gradle plugin imperatively using the apply script method, which is deprecated and will be removed in a future release. Migrate to applying Gradle plugins with the declarative plugins block: https://flutter.dev/go/flutter-gradle-plugin-apply

You are applying Flutter's main Gradle plugin imperatively using the apply script method, which is deprecated and will be removed in a future release. Migrate to applying Gradle plugins with the declarative plugins block: https://flutter.dev/go/flutter-gradle-plugin-apply

How to remove these deprecated gradle settings.

I have solved the problem by following instructions from Flutter Docs: https://docs.flutter.dev/release/breaking-changes/flutter-gradle-plugin-apply

Here is what i have done:

Firstly, I have completely replaced android/settings.gradle file like this:

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
}()

includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")

repositories {
    google()
    mavenCentral()
    gradlePluginPortal()
}
}

plugins {
    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
    id "com.android.application" version "{agpVersion}" apply false
    id "org.jetbrains.kotlin.android" version "{kotlinVersion}" apply false
}

include ":app"

Then, inside the android/settings.gradle file more specifically inside plugins{} I have changed {agpVersion} with 7.2.0 and {kotlinVersion} with 1.7.20

Then, i have removed the whole buildscript{} from android/build.gradle file. Now the android/build.gradle looks like this:

allprojects {
repositories {
    google()
    jcenter()
}
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

tasks.register("clean", Delete) {
    delete rootProject.buildDir
}

Then inside the android/app/build.gradle file i have deleted some lines. Those lines are,

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.")
}

and,

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

Then also in this file i have added some lines at the top. Those lines are,

plugins {
    id "com.android.application"
    id "kotlin-android"
    id "dev.flutter.flutter-gradle-plugin"
}

And lastly, inside dependencies{} of android/app/build.gradle i also replaced $kotlin_version with 1.7.20

So, Now the android/app/build.gradle file looks like this:

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()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
    localProperties.load(reader)
}
}


def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}


android {
    compileSdkVersion flutter.compileSdkVersion

sourceSets {
    main.java.srcDirs += 'src/main/kotlin'
}

lintOptions {
    disable 'InvalidPackage'
}

defaultConfig {
    // TODO: Specify your own unique Application ID 
    (https://developer.android.com/studio/build/application-id.html).
    applicationId "com.fahad.app"
    minSdkVersion 21
    targetSdkVersion flutter.targetSdkVersion
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
}

buildTypes {
    release {
        // TODO: Add your own signing config for the release build.
        // Signing with the debug keys for now, so `flutter run --release` works.
        signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

// See the updated portion of the answer if you're using a more recent version of Flutter and Dart.

dependencies {
    // Eliminate this line (or the entire dependencies block)
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20"
}

So, I just edited 3 files [android/settings.gradle], [android/build.gradle] and [android/app/build.gradle] and the issue is resolved. Hope this helps.

Updated

It's necessary to make one more small adjustment. You need to remove the dependency "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" from android/app/build.gradle after upgrading to Flutter 3.22 and Dart 3.4. Please refer to this section of the migration guide. Additionally, have a look at this line.