The [Tecla Accessibility Service] (https://github.com/idrc/tecla-as) makes use of the Android Accessibility Service framework to provide universal switch access to Android devices. The Tecla Accessibility Service is compatible with devices running Android Ice Cream Sandwich (API Level 14) and above.

The [Tecla Accessibility Service] (https://github.com/idrc/tecla-as) represents a paradigm shift in the way Tecla resolves switch access to the Android framework. Starting from ICS (Android API Level 14), it is possible to perform programmatic navigation and activation of UI elements through the [AccessibilityNodeInfo class] (http://developer.android.com/reference/android/view/accessibility/AccessibilityNodeInfo.html). This has the potential to overcome some of the limitations with the keyboard injection method for control employed in the original [TeclaAccess repo] (https://github.com/idrc/TeclaAccess). Such limitations, like the inability to access modal windows, options menus and the notifications drop-down bar, should all be addressable using the Tecla Accessibility Service.

The proposed user experience paradigm for the Tecla Accessibility Service is based on a semi-transparent overlay similar to heads-up displays (HUD) available in fighter aircraft. The HUD would render sizable switch controls for interaction with the device. It is thus assumed this represents and advantage over the discrete navigation bottom row introduced with the original Tecla Access project for the following reasons:

• A HUD increases the space available for the arrangement of switch controls
• The HUD aims towards a look and feel that unifies switch controls and device navigation into a single integrated user experience.
• The HUD provides limitless visual interaction possibilities that are not tied to the keyboard interaction paradigm provided with the original Tecla Access project.

The image below shows the first mockup of a potential HUD overlay for the Tecla Accessibility Service.