Data entry on mobile devices is particularly tricky because of our fat fingers and the devices’ smaller screens. There are literally hundreds of data entry patterns currently in use, and you could write an entire book specifically on this subject. Actually, my friend and mentor Luke Wroblewski did exactly that by writing an excellent book called Web Form Design: Filling In the Blanks (2008, Rosenfeld Media). In this chapter, rather than covering every conceivable input strategy currently in use, we concentrate on the trickiest aspects of Android forms, which people most often get wrong.
Web page developers for years tried to popularize sliders and make them part of the standard HTML development toolkit. Many rejoiced that sliders came standard with the Android data entry widgets because, frankly, sliders are cool. Unfortunately, along with the sliders came a whole scope of issues that can sometimes be hard to pinpoint.
Sliders come in two types: single and double. In addition to that, each type of slider can enable a continuous adjustment or have a set of predefined positions that customers can select from.
To see how these two types of sliders work, it is instructive to compare two different apps: Trulia and Zillow. Trulia (see Figure 10-1) solves the price data entry problem using a dual slider.
On the other hand, Zillow offers the same price entry but has two ...