The following is the official Batman Injustice Edition theme pulled from a Galaxy S7 Injustice Edition smartphone. You can easily install this following instructions at HighOnAndroid.com. This will convert your Galaxy smartphone into Injustice Edition as far as the theme goes. You can also install on rooted Galaxy smartphone like older Galaxy S4, S5, S6, Note 4, or even Note 5 if you have a ported S7/S7 Edge ROM installed.
Make sure to sign into Samsung account before installing.
What is an APK File?
APK File is a file/app that can be installed on any Android smartphone or tablet. Using an APK file, you can install Android apps manually on your Android device.
You do not need a rooted Android device to install APK files. For installation instructions, please see below.
How to Install APK Files
You will need to make sure Unknown Sources is checked ON in Settings to install APK files. We do recommend you to use a file explorer app such as ES File Explorer, available on the Play Store for free, to install these apps.