An old friend is better than two new ones: dual-screen Android

What is it about?

Dual-screen foldable Android smartphones such as Microsoft Surface Duo are emerging. However, due to its internal design, the Android framework cannot support combined mode, by which two screens can be integrated into one, without modifications, thus requiring new display management. Android introduces a new dual-screen display method, called presentation class, to handle this problem; however, existing apps need to be redesigned based on the new class. In this paper, we propose Dual-Screen Android (DSA), a semantics-aware display scheme for dual-screen foldable Android smartphones. DSA is transparent to apps, thus requiring no changes for existing apps, and incurs minimum modification to the Android framework. Specifically, inside Android, DSA duplicates and maps single-screen views provided by apps to dual screens and maps input events backward correspondingly, thus being transparent to apps. DSA also opens the door to store other hardware states (e.g., screen brightness, screen-touch events, etc.), which can be utilized to bridge other software/hardware semantic gaps for further system optimization. To demonstrate this, we design an effective Q-learning energy optimization scheme within DSA to control screen brightness based on predicted users' behaviors. We have implemented DSA based on Android 10 with real hardware and conducted a series of experiments. Experimental results show that based on DSA, without any modifications, existing apps can directly run and fully exploit dual screens with negligible time and memory overheads, and our energy optimization scheme can effectively reduce energy. We have released the open-source code of DSA for public access.

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Photo by Rami Al-zayat on Unsplash

Photo by Rami Al-zayat on Unsplash