Stroke Dialler For Android

Video: Stroke Dialer For Android

1 Video: Stroke Dialer For Eyes-Free Keypad Input

Device Used: T-Mobile G1 from HTC

The stroke dialer enables one-handed keypad input using thetouch-screen --- and that without having to even look at thescreen. Here is how it works --- we start with a briefdescription of the problem that asks the rightquestion. The answer becomes self-evident as you follow thisvideo.

1.1 The Problem

On-screen keyboards typically show some buttons on the screenthat you activate by touching the screen. To activate suchbuttons, one needs to look at the screen, because the buttons areplaced at specific points on the screen, i.e., they areabsolutely positioned. So what if you want to activate suchbuttons without looking at the screen?From the foregoing description, it's clear that the only reasonone is forced to look at an on-screen keyboard is because thebuttons are absolutely positioned. So let's relax thatconstraint, let's use relative positioning to place thebuttons.

We'll start with a keyboard we're all familiar with, thetelephone keypad. Since we're using relative positioning,let's place the center of the keypad wherever you firsttouch the screen.So, to dial a 5, you just touch the screen.

Now, you know where 5 is --- it's where you first touchdown. But look, since you know the layout of a phone keypad, youcan now find all the other digits relative to the 5. So forexample, 2 is directly above 5 --- so to press 2, youtouch down on the screen, and stroke up before lifting yourfinger.similarly, you stroke down for an 8, or diagonally up for a1.

In real life, we both hear and feel as we press physicalbuttons. This form of synchronized auditory and tactile feedbackis essential for creating user interfaces that feelrealistic. The stroke dialer produces a slight vibration as thefinger moves over the various buttons that is synchronized withan auditory tick to achieve this effect. It also producesspoken feedback to indicate the button that was pressed.

To conclude this video, let's dial a few numbers.

Author: T.V Raman<raman@google.com>