Kotlin Android Apps - Eleftheria Batsou

Objective: Learn Kotlin by creating apps

Technologies: Kotlin, MaterialUI (& Github)

Editor: Android Studio

Duration: About 4 weeks

► To create these apps I followed the tutorial "Android App Development Masterclass using Kotlin" from Udemy, instructed by Tim Buchalka and Jean-Paul Roberts.

► In every application I tried to learn and create something different. These apps are far from perfect, but it's a sample of my work and learning progress. 

► In the future, better apps are going to be added.

1. Calculator App

Calculator - Android app by Eleftheria

About the calculator: It is a very basic calculator where you enter numbers using the apps buttons. It performs the calculation when any of the operation keys are pressed (plus, minus, multiple and divide). It works both in landscape and in portrait view. 


I worked with:

- Group widgets, to see how I can do things like constraining them to be positioned as a group, as well as common properties for multiple widgets at the same time.

- OnClickListener: so that the same method can be used by multiple buttons


code | demo


2. Top 10 Downloader

Top 10 Downloader - Android app - Created by Eleftheria

About the To 10 Calculator app: You can find the top 10 most famous apps currently on app store! Or you can see the same list with 25 results and even change it to show songs, paid, or free apps.


I worked with:

- Downloading data over the internet, running task in the background using AsyncTask (which although in java works well in kotlin it is not recommended)

- Parsing XML to extract data from a download feed

- The list ListView widget for displaying a scrollable list of items (which is not a very modern method, but for simple projects, it works fine)

- Adapters for providing data to ListViews

- Creating a menu/sub-menu for the app


code | demo


3. Simple YouTube Player

Simple youtube player - Android App -Created by Eleftheria

About the simple youtube player: With this app you can see a particular video or a playlist from youtube. There are also small hints while the actions that are being performed, such as "video paused" or "video stopped".


I worked with:

- Youtube android player API and Google API key

- Adding widgets dynamically

- Intents


code | demo


4. Flickr Browser

Flickr Browser - Android App - Created by Eleftheria

About the Flickr browser: It allows us to query and download a list of recent photos from the hugely popular Flickr website.


I worked with:

- Material Design: Google introduced material design in android5, Lillipop (API 21) to encourage good design and allow a consistent user experience across different platforms and device sizes

- Making an app compatible with previous versions

- Downloading JSON data from the web (using AsuncTask)

- Callback functions and interfaces

- RecyclerView and RecyclerViewAdapter (which like a younger brother of the ListView)

- Listening for taps on a RecyclerView, and the purpose of a GestureDetector

- Themes and styles, and a look at how they work for different versions of Android

- Searching with multiple tags 


code | demo