Android Oreo Might Be Fully Themeable, No Root Required
While Android is significantly more customizable than iOS in terms of appearance, for the most part, especially as far as stock Android is concerned, it's still pretty limited. Users who love to tweak every icon, button, color, or font on their device have to hope their OEM allows for some sort of theming, use a ROM that does, or, worst case scenario, root their device to let third-party apps do their magic. Starting Android 8.0 Oreo, however, that might no longer be necessary, as Google seems to have included just enough hooks for the Substratum theming engine to work without rooting your device. With some caveats, of course.
While you can tweak a lot more parts of the Android UI than iOS, in many cases they can only be applied to a limited parts of the interface. A dark theme, for example, usually only applies to the Settings app or other stock UI. Existing theming solutions required root access in order to override system files and settings. Thanks to Sony's open source efforts, however, Android gained a more configurable Runtime Resource Overlay (RRO) framework for themeing, which eventually evolved into the Overlay Manager Service (OMS).
The problem with RRO and even OMS is that they still required root access. Or so we all thought. That was until XDA did some digging and inspired a scavenge hunt that yielded an amazing discovery: you might not need a rooted device to install and use themes. Especially not if you use a new version of the Substratum framework that will be coming in a week or so.
But before you breakout the champagne, you should know that it's not a perfect solution. To some extent, Substratum still needs admin privileges to work but that can be given through a script without rooting the phone. That script, however, needs to be run on a computer and Substratum loses its privileged status at every reboot, meaning you have to grant it privilege again each time your restart your phone. That said, the themes remain installed and the current theme remains applied even when you restart your phone. Lastly due to this "pseudo-root" method, there will still be some things that Substratum will not be able to touch, like system-wide fonts for emojis. Sorry, yellow gum drop.
When the rootless Substratum does land next month, it won't come for free. That might be a shock to those used to getting the rooted version free of charge, but it might be an acceptable tradeoff to help fund an app that everyone wants but most often take for granted.
VIA: XDA