Posted by: Tharindu | April 14, 2020

Survey Article on Blockchain Technology

I have been reading part-time for my Mphil degree since couple of years at University of Kelaniya, Faculty of Computing and Technology, while working full time for Vesess. My main research include working on developing a protocol to simplify management of cryptocurrencies, which is already in progress. The research started with a survey paper on blockchain technology. This has been my very first experience on formal scientific article writing in addition to usual writing I did for academic purposes during my BSc at University of Moratuwa, Faculty of Information Technology. After going through several revisions with the guidance of Kelaniya University mentors (Dr. HD Weerasinghe and Prof. NGJ Dias) and SN Computer Science journal review panel, I was able to get my publication online on Springer.

Within the survey paper, we have aggregated all the core concepts of blockchain technologies for future researchers and readers who are initiating their studies in the particular technology. Once we started researching this technology, many of the concepts were scattered on different sources such as academic journals, technical reports, books, and research papers. With this paper, we believe that we save quite a lot of time for future readers by presenting blockchain technological terms together within a single survey with heaps of useful technical details. The final publication is available at

Cite this article

Gamage, H.T.M., Weerasinghe, H.D. & Dias, N.G.J. A Survey on Blockchain Technology Concepts, Applications, and Issues. SN COMPUT. SCI. 1, 114 (2020).

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I recently realized my Gmail is running out of space and I need to clear up some unused or large Emails, and clean up Google Drive space. I hardly used Google Photos. And most of my space was used by Gmail. In addition to standard 15 GB space I also had 2 GB additional free storage which was acquired by a security check up enabled by Google few years ago. Out of my 17 GB space only 1 GB was used by Drive, 0.02 GB for Photos, and nearly 15 GB by Gmail. I did few things that easily got me nearly 2 GB storage space re-claimed. I would like to list the steps I did, so it would be useful for anyone to quickly claim some useful space for Gmail emails.

  1. How to Re-claim space in Google Drive?
    1.1 Visit the following link to see your files listed from largest to smallest.
    1.2 Put files you don’t want in to the Bin with Right Click & “Remove”
    1.3 Goto Bin from left side navigation. Press Ctrl+A / Cmd+A (Mac) to Select All. Right Click & “Delete Forever”
  2. Read More…

Sanhinda iOS app was my very first personal app, which I have submitted into Apple AppStore way back in December, 2011. The initial version was written in Objective-C and the app helped to type in Sinhala using the English Keyboard on iOS devices. The app got huge attraction in 2011 and reached #1 rank in Sri Lanka Apple AppStore on 22nd December, 2011. The design for this app was done by one of my friend Julian.

After a while, I have totally forgotten this app and recently a person I have met got a requirement to type in Sinhala, but the existing apps on iOS lacked ability to type letters with yansaya (ex. ද්‍ය). What I noticed was my old app was not compatible on iOS 11 and also the app is not having the custom keyboard (This feature was later introduced on iOS 8). I thought I would re-write the app in Swift to support this requirement to help anyone wanted to type Sinhala properly on iOS devices. Therefore, I have re-written the whole app in Swift with an additional Sanhinda Sinhala Keyboard Extension, which could be used to add additional keyboard into iOS device keyboards list. As well as that you could also learn to write using Sanhinda iOS app and its helpful note pad.

To enable custom Sinhala Keyboard:
1. Download and Install Sanhinda iOS app from Apple AppStore.
2. Goto device Settings > General > Keyboard > Keyboards > Add New Keyboard…
3. Select සන්හිඳ Keyboard to add additional keyboard to type.
4. You can switch between keyboards using Globe icon in English keyboard.



I have started developing CoinTracker iOS app as a side project during my spare time, and I first published CoinTracker iOS app to the Apple app store on 28th. September 2017. It garnered a lot of interest very quickly and was loved by almost everyone who used it. Following positive customer suggestions, I have made a number of improvements to make a brilliant product even better.

One of CoinTracker’s strongest features has always been its simplicity and ease of use. It was designed from the start so that even novices could use it. CoinTracker users tell me constantly how much they appreciate being able to track their crypto-currencies without CoinTracker getting in their way. I truly believe it is this simplicity of design and function which sets CoinTracker apart from its many competitors.

And what of the future? Well the good news is, following initial success on iOS, I now have a friend working on producing an Android version as fast as he can. We have been working on the Android version for about one month and its gaining a lot of interest as well since its initial release just like for iOS app.

CoinTracker iOS app reached over 1000 daily active users yesterday 4th. January 2018 (within just over three months from initial release). I was so excited about the success within a short period. When it first reached 100 daily active users I was so happy and I have posted in Indie Hackers forum and got some suggestions on how to bring it to the next level. And those suggestions really helped too and the exponential growth in last three months was amazing. My friends also helped me with suggestions on how to improve the app too addition to lots of feedback came from CoinTracker users.

I would like to thank all CoinTracker users for helping this grow and we would work hard to make the app even better and we have certain plans to introduce unique features in next few months, which were never included with any crypto app before. Stay updated with my blog and our social media channels Facebook, Twitter for CoinTracker latest releases with these new and unique features.

CoinTracker (Cryptocurrency Portfolio Mobile App) has been my pet project for last couple of months and it has been very much appreciated by cryptocurrency users around the world since its first release in late September. As lots of requests came in I was very much excited to give new features for this app during last month. Very much CoinBase like beautiful hourly, daily, weekly, monthly, yearly, and all time charts was one of the many exciting features added during a small amount of time. The last main update with version 1.1.4 was to introduce an in-app purchase to expand the cryptocurrency set support to 1000+ full cryptocurrency list. I was so quick to release this exciting feature in Saturday (4 November) with one time payment of 0.99 USD to unlock full cryptocurrency set. Interestingly it was approved so fast just few hours waiting for review in queue. That was so fast, when I realized the receipt validation had happened against Apple’s Sandbox server. Soon after I have submitted an update 1.1.5 Saturday night itself but had to wait couple of days to get it approved on Tuesday (6 November). This fixed version unlocks portfolio tracking, beautiful charts and all other free features with a limited cryptocurrency set to a cryptocurrency set of over 1000+. I was able to have money for a coffee in a single day (appeared in iTunes Sales Reports) and so excited about encouragement given by its users.




Posted by: Tharindu | September 29, 2017

CoinTracker: Cryptocurrency Portfolio Mobile App

I always had an idea to build a Stock Tracker mobile app and started working on it on my spare time and suddenly had to give up, as there were no free public APIs to access necessary data in different stock exchanges. Meantime one of my Crypto interested friend suggested about this idea about lack of a good cryptocurrency portfolio iOS app, which resulted in changing that Stock Tracker design from light theme into a dark themed Coin Tracker iOS App. The research and development was pretty quick for the initial version and have got so many ideas to extend the basic version into much more sophisticated cryptocurrency app.

Meantime, you would love to download this interesting app from Apple AppStore with following link.

I have added couple of app previews and few screenshots to make you more interested about this app.




The guide for Gitlab Android CI integration contains information on how to integrate CI with Gitlab. But the official guide contains little bit out dated .gitlab-ci.yml file.

The script in yml tries to download a tar file but the latest sdk contains as of zip format. Therefore I had to modify the script slightly to download the right android sdk and set the $ANDROID_SDK_HOME correctly with the above change.

If you have trouble setting up Android CI for Gitlab project please try using the following code in gitlab ci yml file.
If you want to run unit tests for debug only with more details use the following command instead.

./gradlew testDebug --stacktrace


image: openjdk:8-jdk
- apt-get --quiet update --yes
- apt-get --quiet install --yes wget tar unzip lib32stdc++6 lib32z1
- wget --quiet${ANDROID_SDK_TOOLS}
- unzip
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter android-${ANDROID_COMPILE_SDK}
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter platform-tools
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter build-tools-${ANDROID_BUILD_TOOLS}
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter extra-android-m2repository
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter extra-google-google_play_services
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter extra-google-m2repository
- chmod +x ./gradlew
- build
- test
stage: build
- ./gradlew assembleDebug
- app/build/outputs/
stage: test
- ./gradlew test
stage: test
- wget --quiet --output-document=android-wait-for-emulator
- chmod +x android-wait-for-emulator
- echo y | $ANDROID_HOME/tools/android --silent update sdk --no-ui --all --filter sys-img-x86-google_apis-${ANDROID_COMPILE_SDK}
- echo no | $ANDROID_HOME/tools/android create avd -n test -t android-${ANDROID_COMPILE_SDK} --abi google_apis/x86
- $ANDROID_HOME/tools/emulator64-x86 -avd test -no-window -no-audio &
- ./android-wait-for-emulator
- adb shell input keyevent 82
- ./gradlew cAT
view raw .gitlab-ci.yml hosted with ❤ by GitHub
Posted by: Tharindu | December 8, 2016

Hiveage iOS App for Online Invoicing and Time Tracking

During last few months at Vesess, we have put immense effort bringing the Hiveage iOS App. Hiveage mobile app is for online invoicing and time tracking on the go mainly. Some of its other features include sending estimates, billing, managing connections, taxes, discounts, shipping, saved categories, branding and much more. Hiveage iOS app is in par with all other competitive alternatives Freshbooks for invoicing or Harvest for tracking. Hiveage brings all these features comprehensively with unique user experience. Even though app is available only for premium users, Signing up via web site enables to use app in trial mode for two days with full experience.

Hiveage is one of the best online invoicing and tracking tools available today and we’re pretty happy to bring the continuously evolving app for our users.

Here are few resources about our Hiveage iOS App Design, Development and Announcement.

How we designed the Hiveage iOS App

How we developed the Hiveage iOS App

Hiveage iOS App announcement

Posted by: Tharindu | February 22, 2016

RebelMouse Powered iPhone, iPad & Apple Watch Apps

It’s been nearly 3 years since I have first joined RebelMouse and it has been so wonderful to be part of this awesome team. During this time I was very happy to be part of developing some nice RebelMouse powered iOS apps for iPhone, iPad & Apple Watch, which are available to download on Apple AppStore.

TheDodo, RebelLabs, PowerToFly, RoarSummit , Earthables, HigherPerspective


Dodo        IMG_1806                                                                                                                                                                       

Posted by: Tharindu | December 31, 2013

Cricket365 Australia iPhone app for Aussie Cricket Fans

After Cricket365 Sri Lanka initial app, I have worked on the next Cricket365 iPhone App on my free time for Australian Cricket Fans with the help of my friend Julian doing a super looking design. With a beautiful customised iOS7 new look Cricket365 app would be handy to Aussie Cricket Team lovers to get instant News, Videos, Images, Live Scores on their loving Cricket Team. Additionally, Aussie fans can now listen to ABC Grandstand Sports Radio Live Commentary and broadcasts within the app.

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