How do design a slider for a blind person

Question

My question is related to this post

IMHO the user sliding the finger off the screen can easily take the finger to a place where the slider is no longer available. So, they will move their finger back towards the slider and then will only know they truly got there if the slider vibrates or rings.

My Android device has several UI elements (such the four volume slider controls which pop up when you hit the volume keys) UI sliders for blind people: as the person (who is blind), moves their hand along a phone surface, and comes in touch with the slider, the slider knob should immediately jump to the position where the user's finger is and make a sound.

Any ideas, comments, or suggestions?

Answer 1

You should experiment with Android's built in accessibility tool called TalkBack when designing for vision impaired users. Even as a sighted person you can enable TalkBack on your device and experience your app through the same interaction model vision impaired users use.

The first thing to realise though, is that once enabled users don't simply guess where on screen the interactive content is; they use a series of predefined gestures to navigate the app in the order defined by the app's developer and interact with each control as they encounter them (again, using gestures).

This approach is far more forgiving than trying to explain the impact of a user's input once it has already been received, and if you stick to the native controls and annotate them accordingly you should effectively get some reasonable accessibility support for free.