How to obfuscate the source code while building APK of your Android App? – API 34|Android 14

Steps in this session:
1. Create a simple App
2. Build normal APK (non-obfuscated)
3. Build Obfuscated APK

In this video it shows the source code in the APK file for 3 types of APKs built:
1. Debug variant
2. Release non-obfuscated variant
3. Release obfuscated

In this video it refers to the below pages:
– Android developer page: https://developer.android.com/build/shrink-code#kts
– Programmer World page: https://programmerworld.co/android/how-to-get-source-code-from-apk-file-of-an-android-app-api-34android-14/

I hope you like this video. For any questions, suggestions or appreciation please contact us at: https://programmerworld.co/contact/ or email at: programmerworld1990@gmail.com

Details:

Gradle setting:

    buildTypes {
        release {
            isMinifyEnabled = true
            isShrinkResources = true
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }

Complete gradle code:

plugins {
    id("com.android.application")
}

android {
    namespace = "com.programmerworld.obfuscatedcode"
    compileSdk = 34

    defaultConfig {
        applicationId = "com.programmerworld.obfuscatedcode"
        minSdk = 34
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"

        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            isMinifyEnabled = true
            isShrinkResources = true
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation("androidx.appcompat:appcompat:1.6.1")
    implementation("com.google.android.material:material:1.9.0")
    implementation("androidx.constraintlayout:constraintlayout:2.1.4")
    testImplementation("junit:junit:4.13.2")
    androidTestImplementation("androidx.test.ext:junit:1.1.5")
    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
}

Java code of the App:

package com.programmerworld.obfuscatedcode;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);
    }

    public void buttonSet(View view){
        textView.setText("This is programmer world App");
    }

    public void buttonClear(View view){
        textView.setText("Hello Programmer World!!!");
    }

}

XML layout file:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/t"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="38dp"
        android:layout_marginTop="55dp"
        android:onClick="buttonSet"
        android:text="set"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="87dp"
        android:layout_marginTop="50dp"
        android:onClick="buttonClear"
        android:text="Clear"
        app:layout_constraintStart_toEndOf="@+id/button"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Screenshots:

Debug – non-obfuscated code:

Release – non-obfuscated code:

Release – obfuscated code:

APK to JAR conversion command:

C:\Tools\JDK_to_Code\dex-tools-2.1>d2j-dex2jar apk\app-debug.apk
dex2jar apk\app-debug.apk -> .\app-debug-dex2jar.jar

C:\Tools\JDK_to_Code\dex-tools-2.1>d2j-dex2jar apk\app-release-unsigned_non_obfuscated.apk
dex2jar apk\app-release-unsigned_non_obfuscated.apk -> .\app-release-unsigned_non_obfuscated-dex2jar.jar

C:\Tools\JDK_to_Code\dex-tools-2.1>d2j-dex2jar apk\app-release-unsigned_obfuscated.apk
dex2jar apk\app-release-unsigned_obfuscated.apk -> .\app-release-unsigned_obfuscated-dex2jar.jar

C:\Tools\JDK_to_Code\dex-tools-2.1>

Tools used in this session:

Dex2Jar:

https://drive.google.com/file/d/1BaFRPTbhDD7BlPnmToq9AJxB0IAWpwmn/view?usp=drive_link

JD-GUI/ Java decompiler:

https://drive.google.com/file/d/1eZOX6USPyy4Uq6YSXPFZN43OiF5ze75J/view?usp=drive_link