Jeff Carrion Calderon

Android Developer – Senior Level

Phone: 470-***-**** Email: ad125w@r.postjobfree.com

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Professional Summary.

•Concentrated focus on developing Android software programs for 11 years, with 6 Android mobile apps published on Play Store.

•Experienced with MVP and MVVM architectures.

•Experienced with design patterns Decorator, Façade, Factory, Builder, Observer, etc.

•Hands-on development in all the software-driven cycles, such as requirement gathering, design, analysis, coding, testing, and code review.

•Experience in the implementation of Android mobile applications with RxJava, Firebase, Retrofit, and Bluetooth for modern applications using IoT and learning.

•Skilled in performing tests using Mockito, Espresso, JUnit, etc.

•Proactive self-learner who adapts to new technologies, such as Smart Watches, Chromecast, and Smart TV devices, and builds Android apps in Java and Kotlin with Native and Third-Party frameworks.

•Skilled programming in Kotlin and Java.

•Work with Android SDK and Android NDK.

•Experience using Gradle and Jenkins in a continuous build development process in Android mobile application development.

•A keen follower of building robust testing frameworks to detect bugs in the early stages of the development process.

•Apply in-depth knowledge of various frameworks such as Google Maps, Firebase, RxJava, Retrofit, Volley, LeakCanary, Butter Knife, and more.

•Guide the integration into dozens of APIs successfully with highly performant/critical integrations.

•Experience working with deep learning algorithms to optimize and generate better response times.

•Worked with versioning systems such as Git and GitHub

•Kept abreast of industry trends and technologies, being prepared to apply them quickly.

•Partner with cross-functional teams to define new product requirements, features, and functionality.

Technical Skills

•Languages and Tools - Java, Kotlin

•Architectures/Design Patterns - MVC, MVP, MVVM, Singleton, Dependency Injection

•IDEs - Android Studio, Visual Studio, IntelliJ, Eclipse

•Android Libraries, Frameworks and APIs – Jetpack, C standard Library, MPL and MECL libraries, Ksoap2 library, Jersey Library, open-source libraries, Google Maps API, Volley, Junit, Google Places, Retrofit, RecyclerView Animator, Location Services, FloatingActionButton, Google Cloud Messaging, Schematic, REST, Bluetooth Low Energy, NineOldAndroids, JobScheduler, Push Notifications, Espresso, Google Play Services, Mockito

•External Third-Party Libraries, Frameworks and APIs - Fabric, Glide, Google Custom Search, Samsung SDK, Logger, Spork, Dagger, Mosh, Answers, RxJava, RxCache GSON, Robolectric, EventBus, LeakCanary, VidEffects, Robotium

•Android Guidelines - Material Design

•Issue Tracking - JIRA, Jenkins

•Version Control - Git, SVN, GitHub, Tower, BitBucket

•Data Related Tools - NFC (Near field communication) technology, Firebase, SQL, SQLite

•UI Creation - Custom Android views classes and components, Android adapter views like ListView, GridView, and Gallery, Customized List views, Gallery widgets

Professional Experience

Senior Android App Developer – 11-2022 / Current

Delta, Atlanta, GA

https://play.google.com/store/apps/details?id=com.delta.mobile.android

Manage your travel on Delta with access to boarding passes, flight info & more.

The Delta app serves as a comprehensive tool for customers, allowing them to book flights, manage account credits, make payments, check-in for flights, and access airport maps. The app prioritizes user-friendly interfaces and seamless interactions, providing a convenient platform for travelers.

•Contributed to the enhancement and maintenance of the Delta mobile application, focusing on creating new features, fixing bugs, and optimizing the overall user experience.

•Collaborated with the product team to implement new screens and features using Jetpack Compose, adhering to modern Android development practices.

•Implemented and adhered to various architecture patterns such as Model-View-Presenter (MVP), Model-View-Presenter-ViewModel (MVPVM), and Model-View-ViewModel (MVVM) for structuring and organizing the codebase.

•Designed and implemented UI components for various features, ensuring a seamless and intuitive user interface.

•Utilized Jetpack Compose as the primary UI framework for Android development, adopting modern UI development practices to create dynamic and interactive user interfaces.

•Used Figma to translate design concepts into functional and aesthetically pleasing user interfaces, ensuring a seamless and visually appealing user experience.

•Created new models and entities for integrating innovative features into the Delta app.

•Conducted debugging and resolved issues in both Java and Kotlin codebases, addressing both new and legacy bugs.

•Utilized Robolectric and Mockito for unit testing to ensure the reliability and robustness of critical classes.

•Employed Retrofit to make API calls, maintaining efficient communication between the mobile app and server.

•Developed a passport scanner feature using ML Kit, enhancing the app's functionality for passport-related interactions.

•Conducted comprehensive unit testing of the codebase using Jenkins CI/CD integration, ensuring the reliability and stability of the application across different stages of development.

•Integrated Firebase Crashlytics to monitor and analyze application crashes, promptly addressing issues and enhancing the app's overall stability.

•Implemented code quality checks and analysis using SonarQube, emphasizing clean code practices and ensuring adherence to coding standards.

•Managed version control and collaborative development using GitLab, facilitating seamless collaboration among developers and version tracking.

•Engaged in project management activities using Jira (Version1), contributing to sprint planning, backlog management, and ensuring alignment with project timelines and objectives.

•Operated within an Agile development environment, participating in daily stand-ups and contributing to 2-week sprints, fostering a collaborative and adaptive approach to software development.

•Worked on bug fixes and improvements related to profile screens, ensuring a smooth user experience.

Senior Android Mobile App Software Developer – 02-2021 / 11-2022

Exxon Mobil, Irving, TX

https://play.google.com/store/apps/details?id=com.webmarketing.exxonmpl&hl=en_CA&gl=US

Exxon Mobil Rewards+ is a loyalty app that allows you to stay in the comfort of your vehicle while you pay for Synergy™ fuel with your phone. Say goodbye to taking your wallet out and swiping your credit card at the pump. It's simple: create an account in the app, add your preferred payment method, and start earning rewards on your next fill-up at participating Exxon and Mobil stations!

•Implemented new features in Kotlin and converted some existing Java classes to Kotlin.

•Used RxKotlin in conjunction with RxAndroid, and RxBinding libraries to make the app multithreaded and performed asynchronous operations.

•Gathered requirements for the Android app.

•Worked on application from scratch using JetPack components and Android KTX.

•Replaced Firebase JobDispatcher with WorkManager library for scheduling and executing deferrable background work.

•Developed/programmed modules in Kotlin using MVVM app architecture for ease of maintainability and extensibility, as well as improved quality testing.

•Used code combination of ViewModels and LiveData using MediatorLiveData for loading data while handling the Activity and Fragment lifecycles.

•Included Pdfviewer SDK to view in-app receipts for Mobile Payments.

•Improved location-based features, including geocoding and geofencing for station locator feature.

•Worked on the feature to sign up and create a user account for mobile payments.

•Used Dagger dependency injection to inject network modules, view models, and repositories.

•Implemented HTTP Tunneling using HTTP Connect, while being behind a Syntonic proxy server which is used to compute user's eligibility for sponsored data.

•Pair programmed for code reviews and mentored Kotlin developers on Android best practices.

•Added a custom account to the user's device to authenticate back-end services using OAuth 2.0

•Worked with Jenkins instance on continuous integration server and tested all devices authentically.

•Managed Git version control for Android mobile app code base repository using SourceTree.

•Performed unit and system tests with Mockito, Espresso, and Mock Library.

•Detected memory leaks using Leak Canary.

•Improved image loading from the cache using Glide.

Android Mobile App Software Developer – 04-2019 / 02-2021

Dexcom, San Diego, CA

https://play.google.com/store/apps/details?id=com.dexcom.g6

Only use this app if you have the Dexcom G6 or G6 Pro CGM Systems. Always know your glucose number and where it’s heading with the Dexcom G6 and G6 Pro Continuous Glucose Monitoring (CGM) Systems –indicated for diabetes treatment decisions with zero fingersticks and no calibration.

•Worked on an Agile dev team responsible for improving the app’s UI and optimizing multiple functions of the app, which works with a small Bluetooth transmitter that sits under a patient’s skin and sends glucose readings from the patient to their phone, providing continuous glucose monitoring to help patients and their clinicians better manage diabetes.

•Worked on Android wearable device application development.

•Used GIT for source code management by creating different tags, branches & commits according to the various releases made.

•Maintained long and short-range deliverables with the product management team according to product roadmaps.

•Developed/programmed modules in Kotlin using MVVM app architecture.

•Migrated project to AndroidX to use the newest JetPack libraries.

•Used the Jira platform to track productivity and tasks provided to accomplish the project.

•Localized and internationalized the application for 14 different languages.

•Followed internal software development procedures in compliance with medical regulations.

•Developed automated unit tests with JUnit and integration tests with Espresso and UI Automator.

•Performed regular Android team code reviews to ensure overall code quality and adherence to company coding standards and industry best practices.

•Partnered with cross-functional teams to define new product requirements, features, and functionality.

Android Mobile App Developer – 06-2017 / 04-2019

Compass Savings Bank, Birmingham, AL

https://play.google.com/store/apps/details?id=com.compasssavingsbank.mobile HYPERLINK "https://play.google.com/store/apps/details?id=com.compasssavingsbank.mobile&hl=en"& HYPERLINK "https://play.google.com/store/apps/details?id=com.compasssavingsbank.mobile&hl=en"hl=en

Compass Bank takes the power and convenience of our Internet Banking Service and puts it into your mobile phone. If managing your money day-to-day has become complicated and time-consuming, our mobile app is the solution.

•Implemented core banking RESTful services and Executors/JobIntentServices for multithreading.

•Applied Android performance tuning and crash reporting applications.

•Migrated from AsyncTask to Intent Services to load the information from the user.

•Applied Kotlin extension functions to efficiently re-use existing codes and reduce code duplication to its bare minimum.

•Performed technical build work within an MVVM architectural model.

•Added security by encrypting static and dynamic keys and sensitive application data with white-box cryptography using Arxan Key and Data Protection SDK.

•Wrote test cases for a list of acceptance criteria in the Business layer using Mockito.

•Wrote test cases for the presentation layer using Espresso (UI).

•Conducted requirement gathering sessions and wrote high-level detailed designs.

•Made use of Activities and Activities for Result and RecyclerViews in Android to get a better performance of the application.

•Implemented Material Design features of RecyclerView, Toolbar, and CardView

•Worked on asynchronous requests to the server with the Retrofit library.

Android App Developer – 09-2015 / 06-2017

Budget Car Rental, Parsippany, NJ

https://play.google.com/store/apps/details?id=com.budget.androidapp&hl=en_CA&gl=US

Planning your next getaway or seeking an epic road trip? Quickly book a car with the all-new Budget Car Rental app; it is like having your mobile travel buddy. Sign up for Fastbreak to access features that will make your car rental experience easier. As a Fastbreak member, you can skip the line, make quick returns, manage your rental, and customize your account all through the Budget app.

•Created several compound views to match the UI provided by the Android mobile UI team.

•Used support libraries to ensure backward compatibility with older Android versions.

•Programmed in Java and Kotlin.

•Practiced pair programming to lessen the learning curve on Kotlin.

•Saved data locally using SQLite database by performing the CRUD operations on the database.

•Maintained control of versions using GIT and set up a GitHub repository.

•Created a sharing function to allow users to share items with friends using social media APIs.

•Analyzed and determined the time and effort needed to perform a user story for UX design on the Android mobile app.

•Applied Jenkins for continuous integration.

•Persisted wallet items in the database using SQLite.

•Implemented RESTful API calls to retrieve and manage users' rewards, coupons, deals, and gift cards; and apply them to cart items.

•Used LeakCanary to find and fix memory leaks, significantly reducing system crashes

•Retrofit and RxJava are used for RESTful web calls with the GSON library to deserialize JSON information.

•Implemented Image compression strategy for reducing OOM image crashes.

•Implemented Dagger for dependency injection.

Android Developer – 12-2013 / 09-2015

JetBlue, Long Island City, NY

https://play.google.com/store/apps/details?id=com.jetblue.JetBlueAndroid HYPERLINK "https://play.google.com/store/apps/details?id=com.jetblue.JetBlueAndroid&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.jetblue.JetBlueAndroid&hl=en_CA&gl=US"hl=en_CA HYPERLINK "https://play.google.com/store/apps/details?id=com.jetblue.JetBlueAndroid&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.jetblue.JetBlueAndroid&hl=en_CA&gl=US"gl=US

Take JetBlue everywhere you go! Download our award-winning app to book, manage, and check in for your trips, access boarding passes, and more.

•Added Localytics for in-Android app behavior tracking and usage, including location, gender, preferences, and interests.

•Handled Android device on-screen rotation with the onSaveInstanceState and onRestoreInstanceState methods.

•Extensive use of heavy data workloads to show items in a ListView.

•Integrated the Facebook API inside the application.

•Design a GSON representation to parse Web service requests quickly.

•Used SVN as the central repository for version control.

•Stored data in SQLite and with a Content Provider security layer.

•Wrote automated tests (TDD & BDD) with Mockito and Cucumber.

•Helped transition the Android codebase from Eclipse to Android Studio and made use of Android tools in Android Studio for testing and profiling.

•Implemented various user interface components such as WebView, ListView, ImageView, and TextView to display the data for the application.

•Used Intents and Intent Filters to initiate activities and pass information between Activities and Fragments.

Android Developer – 11-2012 / 12-2013

HSN, Inc., St. Petersburg, FL

https://play.google.com/store/apps/details?id=com.hsn.android HYPERLINK "https://play.google.com/store/apps/details?id=com.hsn.android&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.hsn.android&hl=en_CA&gl=US"hl=en_CA HYPERLINK "https://play.google.com/store/apps/details?id=com.hsn.android&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.hsn.android&hl=en_CA&gl=US"gl=US

The award-winning HSN Shop App for Android is everything you know and love about HSN, right on your mobile phone or tablet! Check out the most popular brands that will keep you fabulous from head to toe and everywhere in between.

•Added value encryption in SharedPreferences using AES 128 with the Secure-preferences Library.

•Integrated 3rd party APIs, including SDKs for social networks, advertising, and analytics.

•Helped transition the Android app from MVC to MVP, to achieve a complete separation of concerns, better code reuse, simpler code reuse, and a higher percentage of unit tests.

•Developed Custom Views and Compound Views.

•Worked on Adjust SDK for mobile app marketers, combining attribution for advertising sources with advanced analytics and store statistics.

•Built the UI/UX implementing Fragments, RecyclerView, and Card View UI components.

•Closely worked with the UI/UX team to follow the guidelines as accurately as possible.

•Implemented Fabric Crashlytics and tracked app crashes for bug finding and fixing.

•Used JIRA board to receive and troubleshoot bug tickets from QA and Project Manager.

•Used TeamCity for Continuous Integration and release process for the QA Team.

•Interfaced with multiple web services SOAP and RESTful from data providers.

•Utilized Tabs and Navigation Drawers to switch quickly between application Activities and Fragments.

•Introduced Push Notifications to keep the user engaged with Parse.

•Introduced Dagger 1 for easier decoupling of the modules through dependency injection.

•Configured PayPal Android SDK for ease of payments and user experience (UX).

Education

Bachelor’s (BIO Mathematics)

Universidad Ana G Mendez

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