1st June 2015. Stefano Ruberto's presentation at MobileSoft 2015 (http://mobilesoftconf.org) about our study on hybrid mobile Apps in the Google Play Store. MobileSoft is the ACM International Conference on Mobile Software Engineering and Systems, and it is sponsored by ACM SIGSOFT. Accompanying paper: http://www.ivanomalavolta.com/files/papers/MobileSoft_2015.pdf Abstract: One of the most intriguing challenges in mobile apps development is its fragmentation with respect to mobile platforms (e.g., Android, Apple iOS, Windows Phone). Large companies like IBM and Adobe and a growing community of developers advocate hybrid mobile apps development as a possible solution to mobile platforms fragmentation. Hybrid mobile apps are consistent across platforms and built on web standards. How hybrid apps are performing in production settings is still highly debated, with limited objective evidence. In this paper, we present the first empirical investigation into mobile hybrid apps involving a large number of mobile apps. Our goal is exploratory and we aim at identifying, analysing, and understanding the traits and distinctions of publicly available hybrid mobile apps within their real-life context. The study has been conducted by mining 11,917 free apps and their related metadata from the Google Play Store, and analyzing them from both a technical and end users’ perception perspective.

1. Hybrid Mobile Apps in the Google Play Store:
an Exploratory Investigation
I.Malavolta, S.Ruberto, T.Soru, V.Terragni
GSSI
June 1, 2015
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 1 / 21

2. Presentation structure
1 Context: Hybrid Mobile Apps
Technologies
Issues
2 Study Design
Goals
Research questions
Objects and Variables
Data Extraction
3 Findings
4 Conclusion and Future works
Perceived Values
Conclusion
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 2 / 21

3. Context: Hybrid Mobile Apps Technologies
Hybrid Mobile Apps
Developments technologies
• a possible solution to mobile platforms
fragmentation
• consistent across platforms
• develop using standard web technologies:
HTML5 CSS JAVASCRIPT
• on top of hybrid development framework
I providing a native wrapper
I a generic JavaScript API that bridges all
the service requests to the corresponding
platform API
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 3 / 21

4. Context: Hybrid Mobile Apps Issues
Pros and Cons
Pros
• cross-platform portability
• reuse of existing knowledge of
web developers
• simpler and less expensive
development processes
Cons
• restricted access to hardware
features
• variations on user experience
• decrease in performance
Strong debate about benefits and drawbacks
Observation
As of today, limited empirical investigations have been performed on
hybrid mobile apps
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 4 / 21

5. Study Design Goals
Research Goals
To analyse hybrid mobile apps
• in their actual context of use
• from both the developers’ and end users’
viewpoints
• with a reproducible empirical strategy
I well-defined empirical protocol
I dataset comprising 11,917 apps and 3,041,315
user ratings
I dedicated analysis tool (available online)
1
1
https://github.com/GabMar/ApkCategoryChecker
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 5 / 21

6. Study Design Research questions
Research questions
RQ1 Are hybrid mobile apps distributed in the Google Play Store?
RQ2 What are the most used hybrid development frameworks for
developing hybrid mobile apps?
RQ3 What are the most used 3rd-party web libraries for developing hybrid
mobile apps?
RQ4 How are hybrid mobile apps integrated to the Android platform
and other installed apps?
RQ5 What is the di↵erence in the user perceived value between hybrid
and native mobile apps?
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 6 / 21

7. Study Design Objects and Variables
Objects and Variables
Objects
11,917 free Android apps from the Google Play Store
• large number of available apps
• easy to extract relevant information from app binaries
Reference set of hybrid development frameworks
e.g., Apache Cordova, Appcelerator Titanium, etc.
Publicly available reference list on Wikipedia2 in order to
• have a starting point as complete and up to date as possible
• make our study replicable
2
en.wikipedia.org/wiki/Multiplephoneweb-based_application_framework
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 7 / 21

8. Study Design Objects and Variables
Objects and Variables
Variables (1)
type identify whether the mobile app is
hybrid or native.(RQ1)
frameworkName used hybrid development framework
(e.g. Apache Cordova) (RQ2)
libraries identify the used specific 3rd-party web
libraries (RQ3)
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 8 / 21

9. Study Design Data Extraction
Objects and Variables
Variables (2)
permissions Identify the permissions requested by the app (RQ4)
rating The average rating provided by the users(RQ5)
reviewsCount Number of reviewsa (RQ5)
a
High-quality mobile apps tend to get more reviews in its app lifecycle
[DK13]
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 9 / 21

10. Study Design Data Extraction
Data Extraction
The extraction process
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 10 / 21

11. Study Design Data Extraction
Data Extraction
Extraction - phases 1 and 2
Total
Finance 463
Medical 490
Transportation 438
Travel&Local 484
Health&Fitness 352
Libraries&Demo 418
Business 488
Lifestyle 497
Social 491
Sports 497
Shopping 487
Education 493
Book&References 472
Total
Communication 487
Entertainment 487
News&Magazines 491
Comics 465
Weather 495
Media&Video 483
Productivity 495
Photography 494
Music&Audio 477
Tools 489
Game 492
Personalization 493
ALL 11,917
Replication package with complete apps list downloadable from:
http://cs.gssi.infn.it/hybrid_googleplay_analysis
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 11 / 21

12. Study Design Data Extraction
Data Extraction
Extraction - phase 3
Open source tool to analyse the APK and extract:
type, frameworkName, libraries, permissions and
size.
Example: identify Apache Cordova
The tool checks if the APK contains:
• an XML file in the path
/res/xml/config.xml
• string “org.apache.cordova” in that XML
• a Java class called CordovaActivity.
Tool publicly available at
https://github.com/GabMar/ApkCategoryChecker
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 12 / 21

13. Findings
Findings - RQ1
Presence in the Google Play Store
Finding
3.73 % hybrid mobile apps (445 over 11917)
• significantly uncommon among the top-500 apps within 25 Google
Play categories
• hybrid apps are infrequent in categories requiring closer interaction
with the Android platform and hardware: Photography, Music, Audio,
Tools, Game and Personalization
Note
Clear indicator of a future area of work for developers and vendors of
hybrid development frameworks
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 13 / 21

14. Findings
Findings - RQ2
Used hybrid development frameworks
Finding
Clear winners: Apache Cordova (258) and Appcelerator Titanium (116)
• other frameworks are less used
• in line with informal claims in other research
papers [MCM+13, OT12, CSS12]
Note
Appcelerator Titanium has a spike in the Finance category. It has specific
support for enterprise-level authentication and authorization
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 14 / 21

15. Findings
Findings - RQ3
Third-party web libraries for hybrid mobile apps
# Web library #apps # Web library #apps
1 jQuery 267 11 Underscore 29
2 jQuery Mobile 106 12 Backbone 27
3 Json2 99 13 Jasmine 27
4 Ionic 58 14 Lo-Dash 21
5 AngularJS 55 15 RequireJS 21
6 Google Analytics 38 16 Bootstrap 20
7 Fastclick 35 17 Mobiscroll 20
8 jQuery UI 32 18 Crypto-js 16
9 Moment.js 32 19 Datejs 15
10 Facebook SDK 30 20 TweenJS 14
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16. Findings
Findings - RQ3
...continue
Note
• 16 out of those 20 top used libraries are not specific to mobile
browsers. Developers reuse and build on JavaScript frameworks
already existing in the desktop web area
• Among the top-20 libraries there are two MVC JavaScript
frameworks, namely AngularJS and Backbone
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 16 / 21

17. Findings
Findings - RQ4
Integration to the Android platform and other apps
Finding
hybrid mobile apps are generally in line with native mobile apps
• 17 out of the top 20 permissions are requested to the Android
platform, whereas the remaining 3 permissions are requested to
Google services
I access the Internet and the network connection state
I write to an external storage drive (e.g. an SD card)
I geographic position of the user
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 17 / 21

18. Findings
Findings - RQ5
Perceived value
Finding
The average of end user ratings is: for hybrid 3.75 and for native 3.35
Finding
Native apps have been reviewed in average 6.5 times more than hybrid
mobile apps
• Hybrid and native mobile apps are performing equally with respect
to end users’ star-rating across all categories.
• We can interpret the review count disparity as an indication of the
fact that hybrid mobile apps are neither perceived as too satisfying
nor dissatisfying . (see [HZP09])
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 18 / 21

19. ConclusionandFutureworksPerceivedValues
Futureworks
PerceivedValues
Empiricalstudyfocussingontheenduserperceptionofhybridvsnative
mobileapps
•intheperceivedperformance
•intheperceivedbugginess
•intheinitialdownloadoverhead(appsize)
Empiricalstudyinvestigatinghowhybridmobileappsperformacross
di↵erentplatforms
Surveytargetinghybridappdevelopers
•focusonpractitioners’perceivedstrengths,limitationsandneeds
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20. Conclusion and Future works Conclusion
Conclusion
I.Malavolta, S.Ruberto, T.Soru, V.Terragni Hybrid Mobile Apps June 1, 2015 20 / 21

21. Conclusion and Future works Conclusion
[CSS12] Luis Corral, Alberto Sillitti, and Giancarlo Succi.
Mobile multiplatform development: An experiment for performance analysis.
Procedia Computer Science, 10:736–743, 2012.
[DK13] Diya Datta and Sangaralingam Kajanan.
Do app launch times impact their subsequent commercial success? an analytical approach.
In Cloud Computing and Big Data (CloudCom-Asia), 2013 International Conference on, pages 205–210. IEEE,
2013.
[HZP09] Nan Hu, Jie Zhang, and Paul A Pavlou.
Overcoming the j-shaped distribution of product reviews.
Communications of the ACM, 52(10):144–147, 2009.
[MCM+
13] Emiliano Masi, Giovanni Cantone, Manuel Mastrofini, Giuseppe Calavaro, and Paolo Subiaco.
Mobile apps development: A framework for technology decision making.
In Mobile Computing, Applications, and Services, pages 64–79. Springer, 2013.
[OT12] Julian Ohrt and Volker Turau.
Cross-platform development tools for smartphone applications.
Computer, (9):72–79, 2012.
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