SIF will normally detect if you are running on a rooted device and will refuse to run (it will flash a small message at the bottom of the screen which basically says “illegal access detected.”) You have four options on how to deal with this.
Use Magisk Hide
If you rooted using Magisk, you already have a built-in root hiding mechanism. Simply launch the Magisk Manager app, tap the menu button (at the upper left of the screen, looks like three horizontal lines stacked on top of each other) and from the menu that appears, choose “Magisk Hide.” Scroll through the list of apps and make sure to check the box next to each version of SIF you have installed.
Install the Xposed Framework and use RootCloak
The Xposed Framework is a set of tools and plugins that allow you to tweak many parts of Android. Of particular interest is RootCloak, a module that prevents programs from detecting that your device is rooted.
Xposed can be downloaded here. To install, follow these instructions. Once you have it installed, run the Xposed Installer app, tap the “hamburger button” to access the Xposed menu, and tap “Download.” Use the search button (magnifying lens icon,) search for “RootCloak” and tap it. Then tap “modules” and tap “download” next to the latest available version (this will be the one at the top of the list.) When the downlaod finishes tap “install.” A notification will appear stating that you need to activate the module before it will work; tap on “Activate and Restart.” Once your device has finished restarting, find the RootCloak app and run it. Tap “manage apps,” then tap the + sign on the upper right. Find and tap on the versions(s) of the app you want to RootCloak (they will be listed both by name (e.g. “Love Live,” "ラブライブ！”, etc.) and Android package name (e.g. “klb.android.lovelive_en”, “klb.android.lovelive.”) Repeat for each version of SIF you have installed.
Install suhide
There is now an experimental hack that adds RootCloak-like root hiding. If you are unable to install Xposed/RootCloak then this might work for you. In particular, it is the only root hiding system that I am aware of that is compatible with Android 7.x. It’s called suhide and can be downloaded here. It needs to be configured via the command line (details are in the same post where you found the download) or you can use this unofficial suhide GUI app.
Use a rootpatched APK
If you are having trouble installing Xposed and/or suhide or don’t want to install them for whatever reason, or if you have a device/Android version that Xposed and/or suhide isn’t yet compatible with, then your only other option is to use a rootpatched APK. This is an APK file (Android application file) that somebody has modified to remove the code that checks for root. You can download rootpatched APKs for EN and JP here.
Note that you will not be able to make any in-app purchases if you are using a rootpatched APK (this includes ALL SIF IAPs such as love gems, starter packs, etc.)
IMPORTANT NOTE ABOUT ROOTPATCHED APKS: With the recent crackdown on hackers and hacked accounts, KLab has put out a clear statement about what actions they consider as unacceptable and could result in an account ban. In particular these restrictions include using non-official versions of the SIF app, including rootpatched APKs. Using a rootpatched APK puts your account at great risk for banning, and I highly recommend you switch to the official (as downloaded from the Play Store) version of the app, and use one of the root hiding methods described above.
