Android Login Form in Java

Yet another login form only written in Java that we made last year 2019. No need okhttp dependency

This project is for experienced modders and programmers only and must be able to search on Google for help. We will not explain here

Keep in mind that it is mainly for APK modding and not for general app development purposes

PHP

Add login.php to your server that supports PHP, use 000webhost.com for free webserver. Repo based hosting such as Github does not support PHP

Change URL on public String sUrl on MainActivity.java file

Merging into your project

It's easy, just copy and paste the code into your project and make some changes

See the example folder how the login code was merged into the mod menu project on MainActivity.java file

How to implement to APK:

This is quite different to implement because the code depends on Activity, you can't just call static method via game's onCreate like invoke-static {p0}, Luk/lgl/MainActivity;->Start(Landroid/content/Context;)V so make sure you follow this steps

First, know the game's launch activity/main activity

You can either use APK Easy Tool to view main activity like screenshot below:

Or decompile your game APK using apktool.jar, or any 3rd party CLI or GUI tools, and open androidmanifest.xml and search after <action android:name="android.intent.action.MAIN"/>

In this case, my game's main activity was com.unity3d.player.UnityPlayerActivity

On Android Studio, put main activity of your game APK to public String sGameActivity

Build the project to APK file.

Build -> Build Bundle(s)/APK(s) -> Build APK(s)

If no errors occured, you did everything right and build will succeded. You will be notified that it build successfully

Click on locate to show you the location of build.apk. It is stored at (your-project)\app\build\outputs\apk\app-debug.apk

Now decompile your app-debug.apk.

Copy your decompiled app-debug.apk smali to the game's smali folder. Example ours is com.example.loginform2, we would copy the com folder from (app-debug\smali\com) to the game's decompiled directory (game name)\smali. If the game have multidexes, add your smali to the last classes dex if possible to prevent compilation errors such as Unsigned short value out of range: xxxxx

On the game's androidmanifest.xml, besure that <uses-permission android:name="android.permission.INTERNET"/> exist

Remove the <action android:name="android.intent.action.MAIN"/> like this:

Near the end of application tag, add your new main activity above </application>. com.example.loginform2.MainActivity is your main activity

<activity android:configChanges="keyboardHidden|orientation|screenSize" android:name="com.example.loginform2.MainActivity" android:screenOrientation="portrait">
     <intent-filter>
         <action android:name="android.intent.action.MAIN"/>
         <category android:name="android.intent.category.LAUNCHER"/>
     </intent-filter>
</activity>

Now compile the game APK

It should launch the login screen and successfully launch the activity after login :)

Simple protection in lib

See Main.cpp for example how to check if the user has logged in

There are the codes called Check() and loadLibrary. They are commented out

You may need to protect your dex and lib files for that