This document discusses designing mobile applications. It provides an overview of mobile applications and compares them to web applications. Key differences include limited screen size, various devices/resolutions, inconsistent networks, and battery usage. The document outlines the architecture of mobile apps including presentation, business, and data layers. It provides design guidelines for each layer focusing on usability, performance, and resource optimization for mobile.

1. Designing
Mobile
Applications
Anand Naik
Development Manager, Cross Country Infotech
solutions@crosscountry.com

2. Slide 2
Abstract
This document discusses the architecture of typical mobile applications. It also provides
a comparison between Web and mobile applications. Designers and Architects can
benefit from the design guidelines presented in this document. The document does not
discuss nontechnical issues, such as issues related to resources or development
methodologies, which are faced during the development of mobile applications.

3. Slide 3
Introduction
• The development of mobile applications is not new. The concept is at least a decade
old. However, in the recent past, it has grown at an enormous speed.
• The upsurge of smart phones and mobile operating systems are some of the factors
that drive this growth. In addition, the developer community is encouraged to see
direct access to customers through various channels such as
AppStore, marketplace, and other channels.
• The software industry has matured to a great extent, but the area of mobile
application development still opens up loads of issues.
• Herds of Web application developers are jumping into mobile application
development with the baggage of their Web development experience.

4. Slide 4
What Are Mobile Applications?
• Any software application that uses a mobile phone as a platform to execute specific
tasks is called a mobile application.
• Mobile applications can be native applications that are written by using device-based
software tools.
• They could be browser-based applications that use HTML, JavaScript, or cascading
style sheets or they could be SMS-based applications.
• Mobile applications differ from Web-based applications in various aspects, a
development team needs to consider these differences while making design
decisions.
• The addition of mobility requires considering various factors, which include network
connectivity, device capabilities, power supply, wide range of user interfaces, and
numerous platforms.

5. Slide 5
Mobile Application Architecture and Design
Mobile User
UI Components Event Handlers Presentation
Business Layer Controller
Native Business Service Business
Controller Orchestration Adapters
Layers
Native Data Access
Adapter Controller
Local Services
Native Data Access
API Adapter
Native OS Mobile Ecosystem
Local Data
Storage/Cache
Services Deployed on Application Server

6. Slide 6
Presentation Layer (Contd...)
• The presentation layer primarily has two main components—the UI components and the event
handlers.
• The UI components are visible to the mobile user, for example, a text box.
• The UI components generate events when acted upon by the user.
• These events are caught by the event handlers for further processing. The design of the
presentation layer is important for a rich user experience.
Web Application Mobile Application
Fixed layout orientation Portrait or landscape layouts
Fixed set of resolutions/screen sizes Variety of resolutions and screen sizes
No local caching Local caching
Enough real estate available Limited amount of real estate
Standard input methods New & cumbersome input methods
Consistent network availability with enough bandwidth Inconsistent network availability with limited bandwidth
SSL and encryption support Some old devices may have issues
Continuous power supply Uses battery power

7. Slide 7
Presentation Layer
Design Guidelines
 If your application needs to be portable across devices, it  Consider designing for touch screen and stylus-enabled devices.
should use platform-independent technologies such as
Titanium and PhoneGap.  Keep the rendering logic separate from the business logic.
 Design your application to fit the portrait and the landscape  Validate the input and handle validation errors correctly.
layout.
 Avoid using references to external resources such as images
 The real estate available on the mobile has a direct relation because it makes a network call and thereby consumes network
with user experience. Design your applications to use this bandwidth.
scarce resource. Decide the target resolutions and operating
systems and fit the layout accordingly.  Because complete URLs are not usually visible, it makes a
phisher’s life easy. The application should attempt to use small
 Use consistent and simple navigation. Do not make it overly URLs that are completely visible.
complex.
 On screen keyboard used for input reduces the real estate
 Use local caching as a mechanism to improve user available, limiting the visibility of the screen. UI design should
experience. Do not cache sensitive data in unencrypted take care of this.
format. Do not rely on the cached data to a great extent.
 Navigation varies depending on the device for example iPhone
 Use exceptions carefully. Differentiate between exceptions has only one physical button for navigation while in android, back
and take appropriate actions. button and context menu makes it easier to navigate.
 The mobile keyboard is not as easy to operate as a desktop  Avoid using heavy media files to conserve battery power.
keyboard. Your UI design should allow users to enter
minimum amount of data.

8. Slide 8
Business Layer (Contd..)
• The business layer contains the Business Layer Controller, Business Layer Orchestration, Native
Controller, and the Service Adapter.
• The Business Layer Controller provides an interface to the presentation layer to interact with
the business logic.
• The Business Layer Orchestration carries out various business operations, such as getting
information from the mobile ecosystem through the Native Controller, getting local data
through the Data Access Controller, and calling external service by using the Service Adapter.
• The Native Controller manages calls to Native APIs that are used to get data from the mobile
ecosystem. The Data Access Controller uses the data access adapter to connect to the data
store.
Web Application Mobile Application
Leverages services of powerful application servers Limited services
Fast processing Relatively slow processing
Multiuser support No support for multiple users
Built-in security mechanisms Not highly secure
Enough working (RAM) memory Limited working (RAM) memory
Matured optimization techniques Optimization techniques are not standardized

9. Slide 9
Business Layer
Design Guidelines
 Avoid long running requests that stop user operations.  Leverage the permission model that is used by the device
Handle them gracefully. operating systems.
 Do not cache heavy data in the business layer.  Use the least privilege model for system access.
 Provide additional validation instead of relying on the  Use correct computing algorithms. If the application does
one provided by the presentation layer. not handle critical data, approximations can be done. This
will save extra processing that is required for data
 Optimize network requests by making fewer HTTP accuracy.
requests and thereby reduce network usage.
 Avoid heavy loops as much as possible.
 Minimize polling operations, for example, schedulers
running periodically.  Achieve a balance between server and mobile side
processing to avoid heavy processing on the mobile and
 Prioritize network requests so that more important still have minimum impact on the user experience.
requests are made with inferior network connectivity.
 Leverage SSL (Secure Socket Layer) for better security.
 Combine multiple requests at the application level to
reduce network usage as against when multiple
requests are made.
 Use power manager APIs to check the battery status
and then take processing decisions intelligently. It can
also be used to check the battery status before
executing heavy UI operations.

10. Slide 10
Mobile Ecosystem and Local Services Layer (Contd..)
• The local services layer provides services to the business layer.
• The service includes calls to the mobile ecosystem and local data store. The data store needs to
be used diligently.
• Using the local data store has advantages over network round-trip because it has numerous
benefits in terms of better user experience.
• Native calls can be utilized to get more information from the operating system, which includes
information such as the battery status.
• The data synchronization agent periodically synchronizes the locally cached data to the server.
Web Application Mobile Application
Huge data storing capacity Data storage is limited
Data is secure Data is relatively insecure
No data loss Possibility of data loss
Numerous data types are available Restricted data types are available
Data isolation can be easily managed Requires more efforts for data isolation
Data access is restricted Data access is open to any user of the mobile

11. Slide 11
Mobile Ecosystem and Local Services Layer
Design Guidelines
 Store data locally and synchronize periodically with the  Understand data formats and map them correctly to
server to compensate for any loss of data from the those available on the local data storage.
mobile. Consider batch operation while you synchronize
data.  Choose data formats correctly to avoid extra processing.
 Replicate local data to the server only if necessary.  Other applications on a mobile can get easy access to
files that are stored on the system. Take adequate care to
 Store sensitive data in encrypted format to avoid being secure this access and do not store any sensitive
read my malicious software. information on the file system.
 Use local data for requirements such as storing user  Follow general guidelines to avoid database data
preferences as opposed to storing any sensitive data injection.
such as passwords.
 The operating system may allow application to run in
 Tune the database to increase the performance. background or pause or even shutdown. These events
need to be respected in advance.

12. Slide 12
Conclusion
The concept of mobile applications is a new wave of technology. It’s just the beginning.
There is still a long way to go. We must recognize that the IT industry has matured to a
great extent and that research in various areas of IT will definitely benefit the
development of mobile applications.
This document does not contain a complete list of all issues related to the development
of mobile applications. It only provides important guidelines that are useful in designing
better mobile applications.

13. Slide 13
About Cross Country Infotech
Cross Country Infotech (CCI) Pvt. Ltd. is a part of the Cross Country Healthcare (NYSE:
CCRN) group of companies. CCI specializes in providing a gamut of IT/ITES services and is
well equipped with technical expertise to provide smarter solutions to its customers.
Some of our cutting-edge technology offerings include Mobile, Web and BI Application
Development; ECM and Informix 4GL Solutions; and Technical Documentation, UI
Design and Testing services.

14. Slide 14
Thank You!