Supporting Flexible and Transparent User Interface Distribution across Mobile Devices

The growing trend of multi-device ownerships creates opportunities to use applications across devices. However, the current methods of app development/usage remain in the single-device paradigm, which is far below user expectations. For example, it is currently impossible for users to dynamically partition an existing app across different devices to utilize multiple surfaces. We introduce FLUID, a novel multi-device platform that supports simultaneous operation of multiple devices. FLUID aims to i) distribute the user interfaces (UIs) of a single app across multiple devices, ii) support unmodified legacy apps without extra engineering, and iii) support numerous apps with customized UIs. Previous approaches, like screen mirroring and app migration, do not satisfy those goals altogether. However, FLUID is designed to satisfy the goals. It can efficiently deploy UI objects to different devices by identifying only UI states necessary for accurate rendering. And FLUID can execute the distributed UI objects by supporting cross-device method invocations transparently and synchronizing the replicated UIs across devices. Furthermore, FLUID automatically handles unexpected events that may degrade its usability by efficiently maintaining the distributed UIs up to date. Our evaluation using 20 legacy apps shows that FLUID can transparently support numerous apps and is fast enough for interactive use.