Developing Android Applications with Adobe AIR [36]
The keyboard and the mouse that we have grown accustomed to using to communicate with our digital tools are perhaps now becoming outdated. The human hand, and even the entire human body, may be the interaction method of the future.
This is what we will cover in this chapter.
A Brief History
The first multitouch system designed for human input was developed in 1982 by Nimish Mehta of the University of Toronto. Bell Labs, followed by other research labs, soon picked up on Mehta’s idea. Apple’s 2007 launch of the iPhone, which is still the point of reference today for multitouch experiences and gestures, popularized a new form of user interaction.
More recently, Microsoft launched Windows 7, Adobe added multitouch and gesture capability to Flash Player and AIR, and a range of smartphones, tablets, and laptops that include multitouch sensing capability have become available or are just entering the market. Common devices such as ATMs, DVD rental kiosks, and even maps at the local mall are increasingly equipped with touch screens.
For an in-depth chronology, please read Bill Buxton’s article at http://www.billbuxton.com/multitouchOverview.html.
Exploring the use of alternate input devices in computing is often referred to as physical computing. For the past 20 years, this research has advanced considerably, but only recently has it been reserved for exhibitions or isolated equipment installations. These advances are now starting to crop up in many consumer electronics devices, such as the Nintendo Wii, Microsoft Xbox, and Sony PlayStation Move.
A playful example of a human–computer interface is the Mud Tub. Created by Tom Gerhardt in an effort to close the gap between our bodies and the digital world, the Mud Tub uses mud to control a computer. For more information, go to http://tomgerhardt.com/mudtub/.
For our purposes, we will only use clean fingers and fairly predictable touch sensors.
What Is Multitouch and Gesture?
Multitouch is a technology that is capable of detecting one or more touches (typically via a finger) and movements on a surface simultaneously. A gesture is a series of touches recognized as a pattern and registered as a single event. The reading and interpretation of touches is a task an ambitious developer can tackle, but luckily, platforms are increasingly doing the job for us.
How Does It Work?
The number of touch screen manufacturers is growing rapidly and their engineers are constantly researching new and improved ways to detect touches. The technology is a combination of ingenious hardware and clever software.
Resistive technology requires two flexible sheets, electrically conductive, with vertical and horizontal lines for precision location. The sheets are separated by an air gap or microdots. When pressed firmly, they make contact and a change in the electrical current is registered and sent to a controller. This technology is very accurate and fairly inexpensive, but it does not support multitouch and does not work well with gestures.
Capacitive technology uses a surface made of insulator-like glass, also called a ground plane, and coated with a transparent conductor. Voltage is applied to the surface. The finger works as the capacitor that modifies the surface’s electrostatic field—more specifically, the coupling between row and column electrodes. The controller can determine the location of the touch from the change in capacitance as measured from the four corners of the surface. This technology is durable and accurate, except when the screen is small or the user is wearing gloves, and it is used in many modern PDAs, such as the iPhone and Android-based devices.
Other technologies, used in nonmobile devices or equipment in a controlled environment, include infrared, acoustic digitizer, and in-cell.
The Multitouch Class
The Flash platform synthesizes gestures across platforms. It also provides the tools needed to access the raw touch data. While support for individual APIs can vary, some level of touch capability is currently compatible with