Selected Topics in Computer Engineering ENC-360 Dr. Feda AlShahwan Computer Section Electronic Engineering Department College of Technological Studies

@Feda AlShahwan 1

Selected Topics in Computer EngineeringENC-360

Dr. Feda AlShahwanComputer SectionElectronic Engineering DepartmentCollege of Technological StudiesPublic Authority for Applied Education and Training

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Chapter 2Mobile Applications

Mobile Applications:• Computer programs that are designed and developed to run on small

wireless mobile devicesMobile Apps Development:• Developing apps for mobile devices requires considering the constraints and

demands of the devices and also taking advantage of the capabilities and features of these devices. Mobile devices run on battery, have limited storage capacity and have less powerful processors than personal computers and also have more features such as location detection and cameras. . Moreover, a gaming app, for example, might take advantage of the iPhone's accelerometer.

• Developers also have to consider a wide array of screen sizes, hardware specifications and configurations because of intense competition in mobile software and changes within each of the platforms.

• Mobile application development requires use of specialized integrated development environments.

• Mobile apps are first tested within the development environment using emulators and later subjected to field testing. Emulators provide an inexpensive way to test applications on mobile phones to which developers may not have physical access.

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Chapter 2Mobile Applications

Mobile User Interface Development:• As part of the development process, Mobile User Interface (UI) Design is

also an essential in the creation of mobile apps. Mobile UI considers constraints & contexts, screen, input and mobility as outlines for design. The user is often the focus of interaction with their device, and the interface entails components of both hardware and software. User input allows for the users to manipulate a system, and device's output allows the system to indicate the effects of the users' manipulation. Mobile UI design constraints include limited form factors, such as a mobile device's screen size for a user's hand(s). Mobile UI contexts signal cues from user activity, such as location and scheduling that can be shown from user interactions within a mobile application. Overall, mobile UI design's goal is primarily for an understandable, user-friendly interface. The UI of mobile apps should: consider users' limited form factor, minimize keystrokes, and be task-oriented with a minimum set of functions.

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Chapter 2Types of Mobile Applications

Types of Mobile Applications:Mobile apps are categorized to : Web-based, native apps or hybrid apps.

Native Apps:• A native application (native app) is an application program that has been developed for use

on a particular platform or device.• The term "native app" is often mentioned in the context of mobile computing because mobile

applications have traditionally been written to work on a specific device platform (Apple’s iOS, Google’s Android, Windows Phone or (decreasingly) BlackBerry OS). A native app is installed directly on a mobile device and developers create a separate app version for each mobile device.

• The native app may be stored on the mobile device out of the box, or it can be downloaded from an online store or marketplace such as the App Store or Android Apps on Google Play and installed on the mobile device. Data associated with the native app is also stored on the device, although data can be stored remotely and accessed by the native app.

• Depending on the nature of the native app, Internet connectivity may not be required. • Examples of native apps are Camera+ for iOS devices and KeePassDroid for Android devices.• Ingress is an example of native apps, which is available only in the Google Play Store, it uses

multiple hardware functions on your device, and its interface exists independently from a web browser.

• Another good example of a native app would be Instagram. Although this app is available on both Android and iOS operating systems, each variant is unique to its OS, and incompatible with any other system.

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Native Apps:• There are different programming languages and developing tools for each

platform– If building for Apple’s iOS, your developer will need to use the Objective-C

language—one of the hardest programming languages to master, even for professionals with experience. The good news is that Apple provides its developer community with very good tools. The main one, Xcode, is the tool your developer will use to create your native app.

– Building for Android requires Java. Java is a more common language than Objective-C and has less of a learning curve, so it’s not as challenging to find proven developers. However, the tools available to create apps for Android—including the most popular tool, Eclipse—aren’t as good as Xcode; but a new tool called Android Studio could eventually deliver the same quality of development support as Apple’s tool.

– Windows Phone, while still more popular than BlackBerry, is back in third place. However, it’s strongly supported by Microsoft and is particularly worth considering if building an enterprise app. Apps for Windows Phone are made using the C# or VB.NET languages. Microsoft’s Visual Studio is a great tool for building an app—it’s probably the most developer-friendly of the three main platforms.

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• If a computer application program is compiled to run with a particular processor and its set of instructions, the result can be referred to as native code . If the same program is run on a computer with a different processor, software can be provided so that the computer emulates the old processor. In this case, the same application runs in "emulation mode" and almost certainly more slowly than in native mode on the original processor. (The application can be rewritten and recompiled so that it runs on the new processor in native mode.)

• Minimal computational overhead and additional components.• Because native apps are written for a specific platform, they can interact with and

take advantage of operating system features and other software that is typically installed on that platform.

• Because a native app is built for a particular device and its operating system, it has the ability to use device-specific hardware and software, meaning that native apps can take advantage of the latest technology available on mobile devices such as a global positioning system (GPS) and camera. This can be construed as an advantage for native apps over Web apps or mobile cloud apps.

• The principal advantage of a native app is that it is fast and the app will operate more quickly because native app requires compilation, which is faster than interpretation. Moreover, it is developed for a specific platform.

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Chapter 2

What is Interpreted Software:• An interpreted language is a programming language for which most of

its implementations execute instructions directly, without previously compiling a program into machine-language instructions. The interpreter executes the program directly, translating each statement into a sequence of one or more subroutines already compiled into machine code.

• Does not produce native binary code; at least not in general. Instead, an interpreter converts a program to an intermediate representation, usually a tree, and uses an algorithm to traverse this tree emulating the semantics of each of its nodes.

• With interpreted languages, the code is saved in the same format that you entered.

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Chapter 2

Native vs Interpreted Software• Native software need to be compiled to run in a mobile system

– Often relies on APIs defined in the system– Compiled programs generally run faster than interpreted ones because

interpreted programs must be reduced to machine instructions at runtime. – … Therefore well-suited in situations when developing the system on top

of well-formalized and documented platform?• Interpreted software requires an interpreter that executes a

downloaded program– Often requires APIs defined in language standard– Can modify themselves by adding or changing functions at runtime. It is

also usually easier to develop applications in an interpreted environment because you do not have to recompile your application each time you want to test a small section.

– … Therefore well-suited in situations where software downloading support is added to a proprietary system that does not have a clean architecture, static APIs, memory protection, etc.

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Web Apps:• A Web application (Web app) is an application program that is stored on a remote server

and delivered over the Internet through a browser interface. • Web applications are generalized for multiple platforms and not installed locally but

made available over the Internet through a browser.• They require internet connectivity.• Mobile web apps are Internet-enabled apps that have specific functionality for mobile

devices. They are accessed through the mobile device’s web browser (i.e. on the iPhone, this is Safari by default) and they do not need to be downloaded and installed on the device.

Hybrid Apps:• Hybrid application is one that combines elements of both native and Web applications.• Most applications could be considered hybrid apps. Web apps, such as online banking

services, typically store some content locally; The iOS Facebook app is a hybrid, it uses Three20 as the core UI along with the Facebook SDK but HTML5 for feeds.

• There are actually three types of web apps: traditional, responsive and adaptive.• Traditional web apps include any website. • A responsive web app takes on a different design when it’s opened on a mobile device

(i.e. phone or tablet), altering its design to suit the device it is viewed on.• An adaptive web app, in contrast, doesn’t change its design. It will display the same

design, but will adjust it to fit the different screen size of a mobile device.

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Hybrid Apps:• A ready example of a responsive web app is the oDesk

blog. Below, you can see the tablet view on the left and the mobile view on the right.

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Hybrid application features:• The biggest benefit of web apps is that they are built using the

most popular programming languages—so developer talent is readily available.

• Can function whether or not the device is connected. • Faster and easier to develop. • Easier to maintain and you can change platforms. • The app itself will not be as fast as a native app as it still depends

on the browser speed.• Integration with a device’s file system. • Integration with Web-based services. • An embedded browser to improve access to dynamic online

content.However, a responsive web app has two principal drawbacks:• It can not use any hardware on a device (i.e. an iPhone’s camera)• Its “discoverability” will be reduced because it will not be in any

app stores.

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Chapter 2Comparison between Web-based and

Native Mobile Apps

Comparison of Native App vs. Mobile Web AppComparison Factors:• User interface• Development• Capabilities• Method of delivery• Versioning of the app• Strengths• Weaknesses

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Native Mobile Apps User Interface• Some companies choose to develop both a native app and a mobile

web app. Here’s a side-by-side look at Facebook’s native app and mobile web app:

• Notice that, in terms of the general look-and-feel, there’s little difference between the two, making for a consistent user experience.

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Native Mobile Apps Development

Native Apps Web Apps

Each mobile application development platform (e.g. iOS, Android) requires its own development process

Runs in the mobile device’s web browser and each may have its own features

Each mobile application development platform has its own native programming language: Java (Android), Objective-C (iOS), and Visual C++ (Windows Mobile), etc.

Mobile web apps are written in HTML5, CSS3, JavaScript and server-side languages or web application frameworks of the developer’s choice (e.g. PHP, Rails, Python)

Standardized software development kits (SDKs), development tools and common user interface elements (buttons, text input fields, etc.) are often provided by the manufacturer of the platform

There are no standard software development kits (SDKs) that developers are required to use to make a mobile web app

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Native Mobile Apps Method of Delivery


Downloaded onto a mobile device Accessed through a mobile device’s web browser

Installed and runs as a standalone application (no web browser needed)

No need to install new software

Users must manually download and install app updates

Updates are made to the web server without user intervention

There are stores and marketplaces to help users find your app

Since there is no app store for the Mobile Web, it can be harder for users to find your app

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Native Mobile Apps Versioning of the app

Strengths


Some users may choose to ignore an update, resulting in different users running different versions of the app

All users are on the same version


Typically perform faster than mobile web apps

Have a common code base across all platforms

App stores and marketplaces help users find native apps

Users do not have to go to a store or marketplace, download the app and install the app

App store approval processes can help assure users of the quality and safety of the app

Can be released in any form and any time as there is not an app store that has to approve the app

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Chapter 2Comparison between Web-based and Native

Mobile Apps Weakness


Are typically more expensive to develop, especially if you’re supporting multiple mobile devices

Mobile web apps can’t access all of the device’s features (yet)

Supporting multiple platforms requires maintaining multiple code bases and can result in higher costs in development, maintenance, pushing out updates, etc.

Supporting multiple mobile web browsers can result in higher costs in development and maintenance, etc.

Users can be on different versions and can make your app harder to maintain and provide support for

Users can be on different mobile browsers and can make your app harder to maintain and provide support for

App store approval processes can delay the launch of the app or prevent the release of the app

For users, it may be harder to find a mobile web app because of the lack of a centralized app store (though listings do exist such as Apple’s Web apps and you can request to be listed in them)

Chapter 2

Symbian• Backed by Nokia, Sony Ericsson, Motorola, Panasonic,

Psion, Siemens, many more• C++• Runs on ARM• OO design, well-established architectural principles,

programming style aiming at easing mobile systems development

• Event driven, micro-kernel design• Pre-emptive multi-tasking system• Good power management• Runs from ROM• Rich middleware

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ApplicationEngines

Telephony

Base

Multimedia

NetworkingBluetooth

Comms Infrastructure

InfraredNarrowBand

Protocols

Serial Comms

WAPStack

ApplicationFramework

WAPBrowser Messaging

Java

MIDP

Graphics Security

Application S

ervices

ApplicationProtocols

ApplicationEngines

JavaPhone

Symbian overview

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Chapter 2Platform

Java:• Interpreted byte code• Virtual machine, Configuration (CLDC 1.0-

>CLDC 1.1), Profile (MIDP 1.0->2.0)• Intended as an add-on• Enables sandbox security, MIDP 2.0 also

introducing digital signatures and rights categories

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Chapter 2Platform

• Small size, fits in low-end mobile phones• An important add-on to many systems that

have other main programming support• SavaJe – an all-Java mobile platform• Further info: www.sun.com/java

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Java™ 2 PlatformServersServers

Java 2Enterprise

Edition(J2EE)

Java 2StandardEdition(J2SE)

OptionalPackages

OptionalPackages

Java 2 Micro Edition (J2ME)

Java Virtual Machine KVM

CLDCCDC

MIDPFoundation Profile

Personal Profile

Java Card APIs

CardVM

Desktopmachines

Desktopmachines

High-endconsumerdevices

High-endconsumerdevices Low-end

consumerdevices

Low-endconsumerdevices

Smart-cards

Smart-cards

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Chapter 2Introduction

Palm:• Palm 4.1 based on AMX kernel

– Programs are basically event handling loops– Single threaded– Motorola DragonBall (68000 series)

• Palm 5.0 true multitasking– ARM

• C, C++, Java• Open and modular architecture

– Introduction of 3rd party SW– Introduction of 3rd party HW accessed by related SW -> Easy development

of add-on modules• Further info: www.palm.coml

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Palm Reference Architecture

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Brew:• Aims to be the mobile platform for CDMA phones

– … but claims to be extendable to GSM as well– Marginal (if any) interest in Europe

• Controlled distribution: “Before your application can be certified for distribution, you must provide certain information that will allow you to become an authenticated BREW application developer”– QualComm and its clients (e.g. Operators) may find this

convenient, whereas developers may not like vendor-enforced restrictions

• C, C++, Java• Further info: www.qualcomm.com/brew

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Brew Reference Architecture

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Microsoft CE:• On and off interest in mobile systems• Market leader in PCs, not dominant in PDA/handheld

computers• Windows CE can be installed to different reference

hardware– Pocket PC 2002– SmartPhone 2002

• Compatibility to PC world is an obvious advantage• C, C++, Windows-like APIs• Further info: www.microsoft.com/mobile

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Microsoft Smartphone 2002

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Chapter 2Platform

Linux:• Three levels of systems

– Minimal system environment• One process, deeply embedded

– Intermediate system environment• Mass memory• I/O• Dynamic linking• File system interfaces

– Full system environment• ”Almost” full Linux

• Released systems from e.g. Motorola• Monta Vista Software/Consumer Electronics Edition for core,

application framework also needed• More info: www.embedded-linux.org

Chapter 2Platform

• Do it Your Self• Own operating system• Well-defined interfaces to system

resources• Dynamic and reliable memory and

resource management• Tool chain availability• Key questions: – Who maintains what? – Who invests and for what motivation?

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Overview

Linux

Java Symbian

Microsoft

ProprietaryOS

Full accessto everything

Single companydevelopment effort

No ’own’ developement needed

Open developmentand standards

Guiding consortia

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Chapter 2Summary

• Mobile Application Development• Mobile User Interface Design• Native and interpreter• Mobile platforms

– Symbian OS– Java– Palm OS– Brew– Microsoft CE– Embedded Linux– Do-it-yourself

• Mobile systems require programming skills that incorporate the most incompatible parts of the system– Limited memory and performance– User extensions

• Many available platforms all of which could become the dominant design– Competition, lack of de-facto standards, divergence

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References

• Series 60 Platform Basics” Provides basic information on the Series 60 platform.

• “Introduction to Designing C++ Applications” This manual deals also with the Hello World Basic application, but provides more in-depth descriptions and instructions concerning the application, its structure and implementation

• “Designing C++ Applications” Provides detailed instructions on designing C++ applications for Series 60. It is recommended that you read the Introduction to Designing C++ Applications before this manual

Documents

Selected Topics in Computer Engineering ENC-360 Dr. Feda AlShahwan Computer Section Electronic Engineering Department College of Technological Studies