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Mobile Applications

Applications are no longer limited to just running on a desktop PC or laptop. Instead, we now have

a plethora of devices on which applications can live. Specifically, we will be thinking about smart

phones and tablets. These devices have something in common … they are consumer items that are

generally small enough to be carried with a person. Unlike classic PC desktops which are

physically cumbersome and remain static in a person's office or home, the phone and tablet travel

with people. In other words, they are "mobile". Applications written specifically for phones and

tablets are termed "mobile applications".

How does a "mobile application" differ from a "regular application"? The answer to that is not

always so clear. There are some obvious thoughts. First, the phone and the tablet don't commonly

have keyboards or mice attached. As such, user interaction is primarily performed through touch

and gestures. This changes the way in which UI styling is built. Next, the screen sizes of the

devices and their resolutions vary. This is typically called the devices "form factor". Screens vary

from a few inches to a dozen or more. Tablets and phones often have additional hardware

technologies in them including accelerometers, GPS and other sensors. The network connections

on these devices should not be considered to be "always available" or may be too costly to maintain.

For these reasons and many more, when one is considering an application to be hosted by one of

these devices, there are considerations to be taken into account which are not present for desktop

applications that simply run Windows. Because of the wide variety of new areas to be covered,

there is the need for new frameworks, platforms and tools to support such new application

development. It is for this purpose that IBM built Worklight.

Types of Mobile App architectures

When looking at a Mobile app, there are number of high level architectures that can be employed.

The first is the Web or HTML5 type. In this style, the app is written purely as a web page using a

combination of standardized technologies HTML, DOM, JavaScript and CSS. A key benefit to a

web app is that it can run without modification on a variety of platforms without modification.

Unfortunately, pure web-apps typically require a network connection in order to run as they must be

downloaded for execution. In addition, the browser environment hosting the application is not

commonly as rich in functions that are available to the native applications. Finally, a browser

hosted application may be slower than a native application is the logic has longer "path lengths"

than native apps.

The next type of app is what is termed a "native app". These apps are written using the

programming language native to the device on which it will run. For example, Java for Android.

The user interface is also native. A native app can't be run on a platform for which it was not

designed. For example, an Android native app can't run on iOS. The benefit of a native app is that

it is likely to perform as quickly as possible and will usually appear seamless to other apps on the

platform. The down-side is that the time cost of developing a single app that is to run on a variety

of platforms increases as very little of the code built for one platform can be re-used on a different

platform.

The last type of app is called the "hybrid app" which is a combination or mix of web app

technology and native app technology. In this story, the core of the development remains web app

based however that app is "wrappered" in a natively installable framework. This means that it can

installed in exactly the same fashion as native apps and will be available while disconnected from

the network.

Design guidelines for Mobile Apps

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