Android Main codes

 Here are the steps to generate aab file 1. Create your Keystore  Keystore is the file you should have to sign your AAB file.  Run the following command in Terminal at your project's root directory.  keytool -genkey -v -keystore ttwenty.jks -keyalg RSA -keysize 2048 -validity 10000 -alias ttwenty  After entering this command, you will be asked to fill key's password and some information. 2. Create a reference file to Keystore  Create a file named key.properties at [project root]/android/  storePassword=password from previous step  keyPassword=password from previous step  keyAlias=ttwenty  storeFile=../../ttwenty.jks  if you create with different key alias, please specify it in keyAlias.  For storeFile if you choose to put Keystore file at the root of your Flutter's project directory. This file's path would work. 3. Modify app/build.gradle  Load keystore's properties   Open [project]/android/app/build.gradle, look for android block, and put following code at the top