Samsung has adopted theming solutions within One UI by bundling its devices with a built-in theme engine and a theme store. For the most part, the theme store contains themes made by developers who have partnered with Samsung, which ends up limiting the options that are available on the store because of the approval process involved. But even with the limitations involved, there are workarounds that let users sideload themes of their choice. Now, with Hex Installer, users can build their own custom theme to be used on Samsung Galaxy smartphones running on One UI.
Hex Installer is a theming solution that utilizes the High Contrast theme that is pre-installed on all Samsung Galaxy devices running One UI on Android Pie, like the Samsung Galaxy S10 series, Samsung Galaxy Note 9, Samsung Galaxy S9, and more. Once the High Contrast theme is applied, Hex Installer then allows users to change several aspects of that theme, practically letting them mix and match different theme elements to build a theme that suits their exact preferences.
The app lets users change various color settings such as background color, primary color, accent color, text color, Quick Settings and Notification colors on the main UX. Further, you can also theme several popular third-party applications to a dark base. You can also tweak other settings such as navigation bar height, Quick Settings transparency, and font used. The fact that doing these does not require root or even ADB is just the cherry on top. You can also submit the theme you created, so others can also enjoy your work. There is also a plugin that lets you theme One UI with Android Q elements.
Do note that Hex Installer is a paid application. The app is claimed to work on Samsung Galaxy smartphones which are running on Android 9 Pie firmware with OneUI. The app cannot be used with Samsung Galaxy tablets.