Unable to reduce APK size

Question

I am trying to reduce APK size by enabling minifyEnabled true and shrinkResources true in Gradle file and after enabling when I am building APK its size is not reducing its size is same as before.

Here is how I set my configuration:

apply plugin: 'com.android.application'

android {

compileSdkVersion 29

defaultConfig {
    applicationId "com.mobile.go"
    minSdkVersion 16
    targetSdkVersion 29
    versionCode 19
    versionName "1.18"
    multiDexEnabled true
    ndk.abiFilters 'armeabi-v7a','arm64-v8a'
}
dexOptions {
    javaMaxHeapSize "4g"
}
buildTypes {
 
    debug {
        minifyEnabled true
        shrinkResources true
        useProguard true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

configurations.all {
    resolutionStrategy.force 'com.android.support:multidex:1.0.3'
}
packagingOptions {
    exclude 'META-INF/DEPENDENCIES.txt'
    exclude 'META-INF/LICENSE.txt'
    exclude 'META-INF/NOTICE.txt'
    exclude 'META-INF/NOTICE'
    exclude 'META-INF/LICENSE'
    exclude 'META-INF/DEPENDENCIES'
    exclude 'META-INF/notice.txt'
    exclude 'META-INF/license.txt'
    exclude 'META-INF/dependencies.txt'
    exclude 'META-INF/LGPL2.1'
}
compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}
lintOptions {
    // Returns whether lint should be quiet (for example, not write informational messages such as paths to report files written)
    quiet true

    // Whether lint should set the exit code of the process if errors are found
    abortOnError false

    // Returns whether lint will only check for errors (ignoring warnings)
    ignoreWarnings true

    // Returns whether lint should check for fatal errors during release builds. Default is true.
    // If issues with severity "fatal" are found, the release build is aborted.
    checkReleaseBuilds false
  }

}

dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.12'
implementation project(':logging')
implementation project(':library')
implementation 'com.google.code.gson:gson:2.8.2'
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:design:28.0.0'
implementation 'com.android.support:support-v4:28.0.0'
implementation 'de.greenrobot:eventbus:2.4.0'
implementation 'com.mikepenz:iconics-core:2.5.10@aar'
implementation 'com.mikepenz:google-material-typeface:2.2.0.1.original@aar'
// implementation 'com.google.android.gms:play-services-gcm:15.0.1'
implementation 'com.google.android.gms:play-services-location:17.0.0'
implementation 'com.github.amlcurran.showcaseview:library:5.4.3'
implementation 'com.github.lecho:hellocharts-library:1.5.8@aar'
implementation 'com.android.support:cardview-v7:28.0.0'
implementation 'de.hdodenhof:circleimageview:2.0.0'
implementation 'com.android.support:recyclerview-v7:28.0.0'
implementation 'com.github.PhilJay:MPAndroidChart:v2.2.4'
implementation 'com.parse:parse-android:1.10.0'
implementation 'pl.bclogic:pulsator4droid:1.0.3'
implementation 'com.hedgehog.ratingbar:app:1.1.2'
implementation('com.inscripts:CometChat:7.33.+')
        {
            transitive = true;
            exclude module: 'gson'
        }
implementation('com.inscripts:CometChatUI:7.33.+')
        {
            transitive = true;
            exclude module: 'gson'
        }

implementation 'org.jsoup:jsoup:1.8.1'
implementation 'com.android.support:multidex:1.0.1'
implementation('com.crashlytics.sdk.android:crashlytics:2.8.0@aar') {
    transitive = true;
}
// for push notification
implementation 'com.google.firebase:firebase-core:17.2.1'
implementation 'com.google.firebase:firebase-messaging:20.0.1'
implementation 'com.google.firebase:firebase-auth:19.1.0'
implementation 'com.google.firebase:firebase-database:19.2.0'
implementation 'com.google.firebase:firebase-analytics:17.2.1'
implementation 'com.google.firebase:firebase-crashlytics:17.0.0-beta01'
// Required for Flurry Analytics integration
implementation 'com.flurry.android:analytics:12.0.3'

//Retrofit
implementation 'com.squareup.retrofit2:retrofit:2.5.0'
implementation 'com.squareup.retrofit2:converter-gson:2.5.0'
implementation 'com.squareup.okhttp3:okhttp:3.12.1'
implementation 'com.squareup.okhttp3:logging-interceptor:3.12.1'
}

repositories {
maven { url "https://jitpack.io" }
}
apply plugin: 'com.google.gms.google-services'
apply plugin: 'com.google.firebase.crashlytics'

What am I missing?

Answer 1

In gradle code above,minifyenabled and shrinkresources are true for debug build,please check if you are building apk in release variant.

Other mechanisms to reduce apk size is to convert drawables to webp format as below.

select drawables and right click to get as below.

Then select lossy or lossless encoding because some drawables can't be converted into webp with lossless.

For more techniques,

https://medium.com/@kevalpatel2106/how-you-can-decrease-application-size-by-60-in-only-5-minutes-47eff3e7874e