Jelly Bean Accessibility Explained:Touch Exploration Augmented By Gestures

Jelly Bean Accessibility Explained:Touch Exploration Augmented By Gestures

1 Jelly Bean Accessibility Explained:Touch Exploration Augmented By Gestures

We announced a number of accessibility enhancements in Android Jelly Bean — see our Google IO 2012 announcements and our Android Accessibility talk from I/O 2012. This article gives a user-centric overview of the Jelly Bean interaction model as enabled by touch exploration and navigational gestures. Note that as with every release, Android Accesssibility continues to evolve, and so as before, what we have today is by no means the final word.

1.1 High-Level Concepts

First, here's some shared vocabulary to ensure that we're all talking of the same thing when explaining Jelly Bean access:

Random Access
Enable user to reach any part of the on-screen UI with equal ease. We enabled this as of ICS with touch exploration.
Deterministic Access
Enable user to reliably land on a desired item on the screen. We enable this in Jelly Bean with linear navigation.
Accessibility Focus
The item that the user most recently interacted with — either via touch exploaration or linear navigation receives accessibility focus.
User can activate item having accessibility focus by double-tapping anywhere on the screen.

1.2 Sample Interaction Scenarios We Enable

The combination of random access via touch exploration, backed up by linear navigation starting from the point the user just explored enables users to:

  • Touch explore an application to understand its screen layout,
  • Use muscle memory to quickly touch parts of the display to access familiar application screens,
  • Use linear navigation to reach the desired item when muscle memory is wrong by a small amount.

As an example, when using the Google Play Store, I can use muscle memory with touch exploration to find the Search button in the top action bar. Having found an application to install, I can once again use muscle memory to roughly touch in the vicinity of the Install button; If what I touch is not the Install button, I can typically find it with one or two linear navigation steps. Having found the Install button, I can double-tap anywhere on the screen.

The same use case in ICS where we lacked Accessibility Focus and linear navigation would have forced me to use touch exploration exclusively. In instances where muscle memory worked perfectly, this form of interaction was highly effective; but in our experience, it also tended to lead to breakdowns and consequent user frustration in instances where users almost found the control they were looking for but missed by a small amount.

Having introduced accessibility focus and linear navigation in Jelly Bean, we decided to eliminate the ICS requirement that the user tap on or near a control to activate it — we now enable users to activate the item with accessibility focus by tapping anywhere on the screen. To eliminate spurious taps --- especially on tablets, we made this a double-tap rather than a single tap. Note: based on user experience, we may optionally bring back single tap at some point in the future as an end-user customization.

1.3 Summary

Android Accessibility continues to move forward with Jelly Bean, and will continue to evolve rapidly along with the platform. Please use the Eyes-Free Google Group to provide constructive feedback on what works or doesn't work for you --- what is most effective is to objectively describe a given use case and your particular experience.


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