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 toi)distribute the user interfaces (UIs) of a single app across multiple devices,ii)support unmodified legacy apps without extra engineering, andiii)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.

Being able to use a single app across multiple devices can bring novel experiences to the users in various domains including entertainment and productivity. For instance, a user of a video editing app would be able to use a smart pad as a canvas and a smartphone as a remote toolbox so that the toolbox does not occlude the canvas during editing. However, existing approaches do not properly support the single-app multi-device execution due to several limitations, including high development cost, device heterogeneity, and high performance requirement. In this paper, we introduce FLUID-XP, a novel cross-platform multi-device system that enables UIs of a single app to be executed across heterogeneous platforms, while overcoming the limitations of previous approaches. FLUID-XP provides flexible, efficient, and seamless interactions by addressing three main challenges: i) how to transparently enable a single-display app to use multiple displays, ii) how to distribute UIs across heterogeneous devices with minimal network traffic, and iii) how to optimize the UI distribution process when multiple UIs have different distribution requirements. Our experiments with a working prototype of FLUID-XP on Android confirm that FLUID-XP successfully supports a variety of unmodified real-world apps across heterogeneous platforms (Android, iOS, and Linux). We also conduct a lab study with 25 participants to demonstrate the effectiveness of FLUID-XP with real users.

The growing trend of multi-device ownerships creates a need and an opportunity to use applications across multiple devices. However, in general, the current app development and usage still remain within the single-device paradigm, falling far short of user expectations. For example, it is currently not possible for a user to dynamically partition an existing live streaming app with chatting capabilities across different devices, such that she watches her favorite broadcast on her smart TV while real-time chatting on her smartphone. In this paper, we present FLUID, a new Android-based multi-device platform that enables innovative ways of using multiple devices. FLUID aims to i) allow users to migrate or replicate individual user interfaces (UIs) of a single app on multiple devices (high flexibility), ii) require no additional development effort to support unmodified, legacy applications (ease of development), and iii) support a wide range of apps that follow the trend of using custom-made UIs (wide applicability). Previous approaches, such as screen mirroring, app migration, and customized apps utilizing multiple devices, do not satisfy those goals altogether. FLUID, on the other hand, meets the goals by carefully analyzing which UI states are necessary to correctly render UI objects, deploying only those states on different devices, supporting cross-device function calls transparently, and synchronizing the UI states of replicated UI objects across multiple devices. Our evaluation with 20 unmodified, real-world Android apps shows that FLUID can transparently support a wide range of apps and is fast enough for interactive use.

The growing trend of multi-device ownerships creates a need and an opportunity to use applications across multiple devices. However, in general, the current app development and usage still remain within the single-device paradigm, falling far short of user expectations. We present FLUID, a new multi-device platform that allows users to migrate or replicate individual user interfaces (UIs) of a single app on multiple devices. In addition, FLUID aims to require no extra development effort to support a wide range of legacy apps that follow the trend of using custom-made UIs. To this end, FLUID analyzes which UI states are necessary to correctly render UI objects, deploys only those states on different devices, and supports cross-device function calls transparently. In this demo, we demonstrate several interesting use cases supported by our Android-based FLUID prototype.