Techniques for Unreachable Objects on the Touchscreen

Validation level: 5. CHI, UIST, CSCW and TOCHI paper publication

Large-screen mobile devices have recently been introduced. While they can display more information on the screen, they have raised the issue of thumb reachability during one-handed use. To solve this problem, four factorial combinations of two triggering techniques (Edge and Large touch) and two selection techniques (Sliding screen and Extendible cursor) were designed.
Four one-handed interaction techniques were designed and evaluated to solve the short-thumb problem.

Copy Bibtex Kim, S.; Yu, J. and Lee, G. Interaction Techniques for Unreachable Objects on the Touchscreen. In Proceedings of the 24th Australian Computer-Human Interaction Conference, pages 295-298, ACM, New York, NY, USA, OzCHI '12 , 2012.
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All new methods were preferred, especially with Landscape orientation.
Notwithstanding the additional burden of support interfaces, most of them showed similar task completion time than the Direct method.
In terms of performance, Extendible Cursor methods showed the same or better performance than the Direct method in terms of the accuracy and error count. Sliding screen methods were more erroneous. Reverse movements such as LC and ES are not very favored.
All proposed methods were shown to have a significant advantage for far targets and to be especially helpful in landscape orientations. Most participants agreed that grips were more stable with the new methods. Overall, Edge triggering with Extendible cursor (EC) is proven to the best combination.

There are two triggering methods (Edge and Large touch) and two selection methods (Sliding Screen and Extendible Cursor). Thus, four combinational configurations were proposed by combining two triggers with two selection methods. The configurations names: ES, LS, EC, and LC. For all support interfaces, Direct touch method was always provided by default: participants can choose whether to use support interface or not