Hey there, let's tackle this login bypass issue step by step. I see you've already spent 8 hours trying to modify the app and hit some roadblocks—let's break down why your initial attempts didn't work and what you can try next.

First, let's address why moving the intent-filter to other activities didn't change the launch behavior: most modern apps have runtime login checks baked into their core activities. Even if you set MainActivity as the launcher in the manifest, the code inside MainActivity is almost certainly checking for an active user session, and immediately redirecting to AuthenticationActivity if it doesn't find one. Manifest changes alone can't bypass this logic—it's handled in the app's compiled code (Java/Kotlin converted to smali), not just the manifest file.

Here are actionable steps to get past the login screen:

1. Modify the MainActivity to Skip Login Redirects #

Since manifest tweaks aren't enough, you'll need to edit the app's code to disable the login check. Here's how:

• Use apktool to fully decompile the app:

  apktool d your-app.apk
  

• Navigate to the MainActivity smali files (look in smali/ro/umfquiz/umfquiz/presentation/main/ if the app isn't obfuscated; if it is, you'll need to identify the correct smali files by looking for references to AuthenticationActivity).
• Search for code that checks login status and launches the login activity. This might look like an if statement checking a shared preference, auth token, or user object.
• Comment out or remove the lines that trigger the redirect to AuthenticationActivity. For example, if you find smali code like:

  if-eqz v0, :cond_0
  # ... code that creates an intent for AuthenticationActivity and starts it
  

  You can either delete those lines or force the condition to skip the redirect entirely.
• Recompile the app with apktool b and re-sign it properly (more on signing below).

2. Fix the Signature Issue When Modifying Login Activities #

When you tried adding android:enabled="false" to login activities and couldn't sign the APK, that's likely because other parts of the app depend on those activities (e.g., references in code or manifest dependencies). Instead of disabling them, try this:

• Keep the login activities enabled, but modify their code to immediately redirect to your target activity (like ModeSelectionActivity or MainActivity) when they launch.
• Open the smali file for AuthenticationActivity, and add this code at the start of the onCreate method:

  .method protected onCreate(Landroid/os/Bundle;)V
      .locals 2
      invoke-super {p0, p1}, Landroid/app/Activity;->onCreate(Landroid/os/Bundle;)V
  
      # Add this block to redirect to ModeSelectionActivity
      const-class v0, Lro/umfquiz/umfquiz/presentation/ModeSelectionActivity;
      new-instance v1, Landroid/content/Intent;
      invoke-direct {v1, p0, v0}, Landroid/content/Intent;-><init>(Landroid/content/Context;Ljava/lang/Class;)V
      invoke-virtual {p0, v1}, Landroid/app/Activity;->startActivity(Landroid/content/Intent;)V
      invoke-virtual {p0}, Landroid/app/Activity;->finish()V
  
      return-void
  .end method
  

This way, when the app tries to launch the login screen, it will immediately jump to the learning environment instead.

3. Ensure Your Signing Process is Correct #

A common issue after modifying APKs is improper signing. Make sure you're using a valid keystore:

• Generate a keystore if you don't have one (using keytool):

  keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias my-alias
  

• Sign the recompiled APK with apksigner:

  apksigner sign --ks my-release-key.jks your-app-dist.apk
  

Or use jarsigner if you prefer:

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.jks your-app-dist.apk my-alias

4. Check for Obfuscation or Anti-Tampering #

If the app uses ProGuard obfuscation or anti-tampering tools, you'll need extra steps:

• Use tools like frida (requires a rooted device) to hook into login check functions at runtime and bypass them.
• Use smali analysis tools to trace references to AuthenticationActivity and identify the core login validation logic.

Reference: Your AndroidManifest.xml Snippet #

<application android:allowBackup="true" android:appComponentFactory="androidx.core.app.CoreComponentFactory" android:icon="@mipmap/ic_app" android:label="@string/app_name" android:name="ro.umfquiz.umfquiz.presentation.UMFQuizApp" android:supportsRtl="true" android:theme="@style/AppTheme">
 <meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/facebook_app_id"/>
 <meta-data android:name="com.google.android.gms.ads.APPLICATION_ID" android:value="@string/admob_app_id"/>
 <activity android:name="ro.umfquiz.umfquiz.presentation.login.AuthenticationActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden|adjustPan"/>
 <activity android:name="ro.umfquiz.umfquiz.presentation.login.FirstActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:name="ro.umfquiz.umfquiz.presentation.login.RegisterActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:name="ro.umfquiz.umfquiz.presentation.login.LoginActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:label="@string/app_name" android:name="ro.umfquiz.umfquiz.presentation.main.MainActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden">
 <intent-filter>
 <action android:name="android.intent.action.MAIN"/>
 <category android:name="android.intent.category.LAUNCHER"/>
 </intent-filter>
 </activity>
 <activity android:name="ro.umfquiz.umfquiz.presentation.ModeSelectionActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|screenSize" android:label="@string/app_name" android:name="com.facebook.FacebookActivity" android:theme="@style/com_facebook_activity_theme"/>
 <activity android:exported="true" android:name="com.facebook.CustomTabActivity" android:screenOrientation="portrait">
 <intent-filter>
 <action android:name="android.intent.action.VIEW"/>
 <category android:name="android.intent.category.DEFAULT"/>
 <category android:name="android.intent.category.BROWSABLE"/>
 <data android:scheme="@string/fb_login_protocol_scheme"/>
 </intent-filter>
 </activity>
 <activity android:label="@string/training_mode" android:name="ro.umfquiz.umfquiz.presentation.testselection.training.TrainingSelectActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:label="@string/exam_mode" android:name="ro.umfquiz.umfquiz.presentation.testselection.exam.ExamSelectActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
 <activity android:label="@string/title_activity_quiz" android:name="ro.umfquiz.umfquiz.presentation.quiz.types.exam.QuizExamActivity" android:screenOrientation="portrait" android:windowSoftInputMode="stateAlwaysHidden"/>
</application>

内容的提问来源于stack exchange，提问作者Panda YT CANAL VECHI