What do I use now that Obfuscated is not working in Kotlin or Java Code?

Question

I try to obfuscate my project so that I enable a few settings in Gradle. then I try to reverse the code but not fully obfuscate

I refer many sites I did not find an exact solution yet

I try to decompile very famous apps like any google app & Facebook from the play store (code seems fully obfuscated).

can anyone give a suggestion of what should I do exactly to make full code obfuscate

• Below 3 Steps No use for code obfuscate

Step 1: Gradle Properties:

# Kotlin code style for this project: "official" or "obsolete":
kotlin.code.style=obsolete
android.enableR8.fullMode=true

Step 2: App level Gradle:

 buildTypes {
        release {
            useProguard true
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

Step 3: proguard-rules.pro I also try proguard rules

# If you keep the line number information, uncomment this to
# hide the original source file name.
-renamesourcefileattribute SourceFile

Here is my kotlin code :

package com.android.myapplication
import android.os.Build
import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        Log.d("myTag","on create")
        try{
            val deviceInfo = " MOBILE: Android" +
                    " APP VERSION:" + BuildConfig.VERSION_NAME +
                    " MODEL:" + Build.MODEL +
                    " Manufacture:" + Build.MANUFACTURER +
                    " BRAND:" + Build.BRAND +
                    " SDK:" + Build.VERSION.SDK +
                    " OS: " + Build.VERSION.RELEASE
            //Sets the text to be displayed.
            android_info.text =deviceInfo
        } catch (e: Exception){
            android_info.text =e.message
        }

    }
}

here I try to reverse code my release build. Android Apk decompiler: http://www.javadecompilers.com/apk

Decompiler output:

package com.android.myapplication;

import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import java.util.HashMap;
import p000a.p002b.p003c.C0034n;
import p082c.p083a.p084a.C0741a;

public final class MainActivity extends C0034n {

    /* renamed from: o */
    public HashMap f2788o;

    /* renamed from: o */
    public View mo2896o(int i) {
        if (this.f2788o == null) {
            this.f2788o = new HashMap();
        }
        View view = (View) this.f2788o.get(Integer.valueOf(i));
        if (view != null) {
            return view;
        }
        View findViewById = findViewById(i);
        this.f2788o.put(Integer.valueOf(i), findViewById);
        return findViewById;
    }

    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView((int) R.layout.activity_main);
        Log.d("myTag", "on create");
        try {
            TextView textView = (TextView) mo2896o(R.id.android_info);
            C0741a.m1859a(textView, "android_info");
            textView.setText(" MOBILE: Android APP VERSION:1.0 MODEL:" + Build.MODEL + " Manufacture:" + Build.MANUFACTURER + " BRAND:" + Build.BRAND + " SDK:" + Build.VERSION.SDK + " OS: " + Build.VERSION.RELEASE);
        } catch (Exception e) {
            TextView textView2 = (TextView) mo2896o(R.id.android_info);
            C0741a.m1859a(textView2, "android_info");
            textView2.setText(e.getMessage());
        }
    }
}

Notes: After enabling the above Gradle setting:

• App size is reduced 40%
• It also removed unused classes & res files in my project.

Answer 1

It is not possible to obfuscate 100%, because the entry-points would get lost. For example, if you'd obfuscate MainActivity, then the reference in the AndroidManifest.xml would become invalid and you couldn't launch it anymore. This is working as intended, there's nothing to worry about.