6 Weeks of Android App Development – FREE Project Based Learning

Are you among the ones who want to learn Android App Development from the beginning? Are you someone who doesn’t have any idea about Android App Development? Or you have just started your journey, but you don’t know whether you are on the right path or not. So, during your initial journey, all you need is proper guidance. If you get your guide, then you are ready to go. Yes, that’s why we have prepared a complete article on this. To help you with this, we have created a practical roadmap for “6 Weeks of Android App Development – Project-Based Learning”. We will learn Android App Development by developing 6 Android Projects. As is said before in this article, Best Way to Become Android Developer – A Complete Roadmap

The best way to learn Android is by developing some basic projects to some advanced projects.

This article is designed in such a way that you are going to learn Android concepts each week by developing a project which is also known as “Project Bases Learning“. This learning will give you the complete guidelines to build strong conceptual knowledge in Android and achieve your Android Developer goal. 

Prerequisite

So, the very first prerequisite for entering into the Android Development World is your “Dedication” and “Motivation” towards learning and building awesome Android apps. Yes, that’s true. First, find a strong reason why you are entering this world. For example, you are practicing Data Structure and Algorithms, day and night for the reason that you are going to get a job in a top product-based company. Similarly, ask yourself,” Why Android? Why not Web Development? Why not Data Science and Machine Learning? If you find the answer, then no one can stop you from learning Android App Development. 

The second one is Programming Language. In Android, programming is done in two languages: JAVA or Kotlin and XML(Extension Markup Language). The XML file deals with the design, presentation, layouts, blueprint, etc (as a front-end) while the JAVA or KOTLIN deals with the working of buttons, variables, storing, etc (as a back-end). So all you need is to have knowledge of Java or Kotlin and XML. 

Note: We have prepared this tutorial in both Java and Kotlin languages. (3 Projects in Java and 3 Projects in Kotlin). 

Some useful learning resource links are available at Lazyroar:

• Java Programming Language 
• Kotlin Programming Language
• XML

Why Native Android? Why Not a Hybrid App?

A native app is a smartphone application developed specifically for mobile operating systems like Java/Kotlin for Android and Swift for iOS. Since the application is developed within the mature ecosystem following, the technical users and the user guidelines experience provided by the OS itself, like the swipe gestures or alignment on the left side of the center, for Android and iOS. Now of course they offer the fastest and the most reliable and most responsive experience to the user. The app will have the look and feel and consistency within most native apps which are built-in into the devices. Native applications have the significant advantage of easily accessing and utilizing the user’s devices’ built-in capabilities. For example, GPS, maybe your address book or your camera, and tons of other things. 

Well, on the other hand, if we talk about the Hybrid applications, they are in the core website package wrapped in a native wrapper, sometimes PhoneGap or others. They look and feel like a native app but ultimately outside the basic frame of the application. They are powered by the company’s website itself. For example, sites like Facebook or Netflix do not really make sense to have a native app platform or even recompile their app for just one feature. It’s going to take a lot of time, and it’s too heavy, so it really makes sense for them just to get started with the Hybrid application. Now, hybrid apps can also use native functionality like the Camera and GPS, but via some third-party plugins, a lot of code needs to be enclosed with that, while on the other hand, the native applications are pretty easy to use and utilize those functionalities, like the Camera or your GPS.   

In the real industry world, what happens is, if you are starting your career in a startup company that is working on Hybrid Apps, and when the company is funded and the team size increases, then they generally switch to Native app development. Also, keep in mind that the salary point of view of Native app developers is actually a little higher and is on top of the Hybrid app developers.  

Who Can Learn Android App Development?

“Degree Doesn’t Matter“, Yes!! If you are doing B.Sc (Computer Science), BCA, or any other degree can also learn Android App Development. All you need is “Coding Skills“. In Android Development there is no need for deep knowledge in Data Structure and Algorithm, you just have to learn Java/Kotlin in advance to be a better Android App Developer. 

System Requirements (Windows | Mac | Linux)

For Windows:

• Microsoft Windows 7/8/10 (32-bit or 64-bit)
• 4 GB RAM minimum, 8 GB RAM recommended (plus 1 GB for the Android Emulator)
• 2 GB of available disk space minimum, 4 GB recommended (500 MB for IDE plus 1.5 GB for Android SDK and emulator system image)
• 1280 x 800 minimum screen resolution

For Mac: 

• Mac OS X 10.10 (Yosemite) or higher, up to 10.13 (High Sierra)
• 4 GB RAM minimum, 8 GB RAM recommended (plus 1 GB for the Android Emulator)
• 2 GB of available disk space minimum, 4 GB recommended (500 MB for IDE plus 1.5 GB for Android SDK and emulator system image)
• 1280 x 800 minimum screen resolution

For Linux:

• GNOME or KDE desktop. Tested on Ubuntu 14.04 LTS, Trusty Tahr (64-bit distribution capable of running 32-bit applications)
• 64-bit distribution capable of running 32-bit applications
• GNU C Library (glibc) 2.19 or later
• 4 GB RAM minimum, 8 GB RAM recommended (plus 1 GB for the Android Emulator)
• 2 GB of available disk space minimum, 4 GB recommended (500 MB for IDE plus 1.5 GB for Android SDK and emulator system image)
• 1280 x 800 minimum screen resolution

What After Android App Development?

• Implement your unique idea by developing an Android App.
• Build an Android App for your college minor and major projects.
• Take freelance Android projects and earn money during your college days.
• Participate in Hackathon.
• Apply for Internships in different companies, etc.

Let’s Get Started

Very Very Important Point: Please don’t copy-paste the code completely. First, try to understand the logic. And play around with it by putting different logic, values, etc. This will help to increase your development skill.

1st Week

On day 1 of “6 Weeks of Android App Development,” you must research and read some blogs related to Android and keep yourself motivated for Android App Development. Blogs like “Best Way to Become Android Developer – A Complete Roadmap“, “Why Kotlin will replace Java for Android App Development“, “Interesting Facts About Android“, “History of Android“, “How Does Android App Work?“, etc. 

Then, in the 1st week of “6 Weeks of Android App Development – Project-Based Learning“, you are going to learn how to set up an Android Studio for Android App Development, How to Create a New Project in Android Studio, How to Run Your Project on a Real Device or Emulator and also you are going to develop two basic Android Apps in 1st week. In this part, you are just going to create the following two very basic android apps

1. The very famous “Hello World” Android App
2. Android app to add two numbers 

So excited!! Let’s begin!

Android Studio Setup

Before setting up Android Studio, let’s install it on your system.

• For Windows/Mac: Install and Set up Android Studio
• For Linux: How to Install Android Studio on Ubuntu?

So assuming that you have successfully installed the Android Studio and you are on the screen below now.

So just click on the “Create New Project” and on the next screen, you can see lots of Activities(mark this word) are there. You can explore each activity, but for a beginner, let’s choose Empty Activity and move further for a beginner 

Here you are going to learn the 1st important concept in Android i.e Activity. You may refer to the following articles to get an idea about what an activity is in Android. 

• Introduction to Activities in Android   
• Different Types of Activities in Android Studio

Now on the next screen 

• Name: Write down your suitable project name.
• Package name: Let’s keep it by default.
• Save location: Choose the location where you want to save this project.
• Language: Choose your language between Java and Kotlin
• Minimum SDK (Mark this word): As you know, Android released its version at regular intervals of time and they provide some new features in the latest version which are not supported by the older versions. So you have to choose which user base you want to hit. Suppose you select “API 21: Android 5.0 (Lollipop)”, then you can see “Your app will run on approximately 94.1% of devices”. Otherwise, you can click on the “Help me choose” button also.

Finally, click on the Finish button.

Here you are going to learn the 2nd important concept in Android i.e SDK. You may refer to the following article to get an idea about what SDK is in Android.

Android SDK and it’s Components 

After click on the finish button Congratulations, the first Android Studio project is ready. Initially, it shows the tip of the day, which gives tips to improve work efficiency. Before going to explore the Android Studio, get familiar with the initial screen which is shown below.

For a better understanding of the Android Studio environment, it has been divided into 4 parts:

1. Menu Part: In this section, it provides options to create a new project, open an existing android studio project, a button to run the application, dropdown for selecting the desired device to run and test an application on.

2. Coding Area: This section provides for writing code for files like .xml, .java, .kt. It allows you to open multiple files at a time in different tabs, but it allows you to edit one file at a time.

3. Project Structure: This area allows us to explore every file of the project. There are various views of the structure. Android is a summarised view of the project structure hierarchy and Project is a detailed view of the project hierarchy. Have a look at the following image.

4. Current Execution Part: One of the most important parts of the Android Studio environment. It provides a detailed view of the current execution of the process or activity. It shows what errors, build outputs, logcat results, etc.

Understanding the Designing Part

All the UI layouts of the application can be found under the res/layout directory. These are of the .xml extension, responsible for building the UIs for application. Android Studio provides two types of ways of designing UI for applications. One is Text, where one needs to design the UI by hardcoding and one is the Design section that provides a convenient drag and drop mechanism for building UI. Have a look at the following image which shows how the code is being written, it goes on to show the result in the right pane.

The following image shows the drag and drops environment for widgets to pick and add in the UI of the application. One can switch to the Design layout by clicking on the bottom left button, shown as the following.

Understanding the Coding Part

As we have understood the design part similarly, another main part is the coding part. In the image below you can see a file named MainActivity.kt. Yes, this is the file where you write the backend part. The logic part. For example, you want to add two numbers. So, after entering two numbers in the EditText, when the user clicks on the Button, it will give the output as the sum of two numbers. So to calculate the sum, you have to write the logic in its part.

Note: If you select Language as Java during project creation, then the file name will be MainActivity.java.

Run Android App

To run an application there are two ways to do it. One is using an emulator, another is using a physical device by connecting it through a USB cable. Refer to How to install Android Virtual Device(AVD) how to set up an android virtual device or refer to How to Run the Android App on a Real Device? setting up a real physical android device and running applications on it. Have a look at the following video on how to run your very famous “Hello World Android App” in your Android Emulator.

Yes!! You have successfully built your first Android App. Now let’s built the second one “Android App to add two numbers“

Step By Step Implementation of Project 1: Android App to Add Two Numbers

Step 1: Similarly, create a new project but this time chooses Java as the programming language. Choose the name of the project by yourself.

Step 2: First of all go to the XML file

Now go to the Code section and write the code for adding 3 TextView, 2 EditText, and 1 Button and Assign an ID to each component. Assign margin-top, left, right for the location.

Here you are going to learn other important concepts in Android i.e What’s RelativeLayout? What’s TextView? What’s EditText? and What’s Button? You may refer to the following articles to get an idea about what those are?

• RelativeLayout in Android
• TextView widget in Android with Examples
• EditText widget in Android  with Examples
• Button in Android

So we are going to develop the UI something like that

Below is the code for the activity_main.xml file. Comments are added inside the code to understand the code in more detail. Refer to the code in detail and you can change the value and play with the UI. 

Step 3: Working with the MainActivity.java file

In this file, we are going to write the logic for adding two numbers. Let’s have a look at the following code. Don’t worry we are going to explain each line of code in detail. 

Explanation:

The package name of your Android app. 

package com.example.addtwonumbers;

List of libraries used in your app.

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

Variable number1, number2 for input number (EditText). Similarly add_button variable is for our Button used in the XML code and the result variable is for TextView.

EditText number1;
EditText number2;
Button add_button;
TextView result;

Remember you have assigned an ID for each component in the XML file. Yes, they are going to use it here. By ID we can use each component which id is assigned in the XML file like the following.

number1 = (EditText) findViewById(R.id.editText_first_no);
number2 = (EditText) findViewById(R.id.editText_second_no);
add_button = (Button) findViewById(R.id.add_button);
result = (TextView) findViewById(R.id.textView_answer);

And at last, we add a setOnClickListener() to our Button. So when the user clicks on the Button this will give us the Output. And inside that, we have written simple logic to add those numbers. And also setText() for our output TextView. As simple as that. That’s it. 

add_button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                double num1 = Double.parseDouble(number1.getText().toString());
                double num2 = Double.parseDouble(number2.getText().toString());
                double sum = num1 + num2;
                result.setText(Double.toString(sum));
       }
});

Yes, you have successfully developed an Android App which takes two numbers from the users and adds them. Now run the app as before and you can see the output as follows. 

Output:

For the complete article please refer to this: Android App to Add Two Numbers

2nd Week

In the 1st week, you have built a very very basic android app that takes only two numbers and adds them. And there are only some lines of code to perform this action. So you have got some basic ideas about android app development now. Let’s move toward the next project, “A Scientific Calculator Android App” which looks like this. 

Note that we are going to implement this project using the Kotlin language. Don’t worry Kotlin is similar to Java. Let me share some tips in Android Studio here. 

1. How to Convert Java Code to Kotlin Code in Android Studio?
2. How to Convert Kotlin Code to Java Code in Android Studio?

What we are going to learn by building this project?

• Use different colors in your android app.
• Build some complex UI in Android and make the app’s UI awesome.
  • RelativeLayout and LinearLayout. And the difference between them.
  • CardView
• Writing some simple logic for simple math calculation.
• Toast in Android 

Step By Step Implementation of Project 2: Scientific Calculator Android App

Step 1: Create a New Project

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Kotlin as the programming language this time.

Step 2: Adding new colors to the colors.xml file 

Navigate to the app > res > values > colors.xml file as below screenshot.

And add the below code to it for different colors. 

Step 3: Working with the activity_main.xml file

Navigate to the app > res > layout > activity_main.xml and add the below code to that file.  What we have used in this file:

• RelativeLayout
• TextView
• CardView
• LinearLayout
• Button

We have already provided you the necessary referral links for this term. You may read them carefully. Below is the code for the activity_main.xml file. You may play with these values and see how the code works.

Step 4: Working with the MainActivity.kt file

So as we have discussed earlier the backend part is written in this file. The backend part means the simple logic part. And for this project, we are going to write the code in the Kotlin language. 

4.1: Creating variables for our TextView and Button

lateinit var tvsec: TextView
lateinit var tvMain: TextView
lateinit var bac: Button
lateinit var bc: Button
lateinit var bbrac1: Button
lateinit var bbrac2: Button
--------------------------
--------------------------
--------------------------
// similarly create variable for all the TextView 
// and Button you have declared in the XML file

4.2: Initializing all the variables

tvsec = findViewById(R.id.idTVSecondary)
tvMain = findViewById(R.id.idTVprimary)
bac = findViewById(R.id.bac)
bc = findViewById(R.id.bc)
--------------------------
--------------------------
--------------------------
// similarly initialize all the variables

4.3: Adding onClickListener() to all the Buttons

b1.setOnClickListener {
  // on below line we are appending 
  // the expression to our text view.
  tvMain.text = (tvMain.text.toString() + "1")
}
b2.setOnClickListener {
  // on below line we are appending 
  // the expression to our text view.
  tvMain.text = (tvMain.text.toString() + "2")
--------------------------
--------------------------
// similarly Add onClickListener() to all the Buttons

At last write down the dimple logic for all the calculations (Addition, multiplication, division, etc.). Let we are going to write the code for the factorial of a number. So write down the code as below:

fun factorial(n: Int): Int {
        // this method is use to find factorial
        return if (n == 1 || n == 0) 1 else n * factorial(n - 1)
    }

Below is the complete code for the MainActivity.java file. Comments are added inside the code to understand the code in more detail.

Output:

For the complete article refer to this: How to Make a Scientific Calculator Android App using Android Studio?

You may also refer to the following video:

3rd Week

In the 3rd week of Android App Development, we will learn the following very important concepts

1. What’s REST API
2. Volley Library in Android
3. What’s a JSON file?
4. JSON Parsing in Android using Volley Library

1. What’ REST API

REpresentational State Transfer (REST) is an architectural style that defines a set of constraints to be used for creating web services. REST API is a way of accessing web services simply and flexibly without having any processing. 

To read more refer to this article: Introduction to REST API

2. Volley Library in Android

Volley is an HTTP library that makes networking very easy and fast, for Android apps. It was developed by Google and introduced during Google I/O 2013. It was developed because there is an absence in Android SDK, of a networking class capable of working without interfering with the user experience. Although Volley is a part of the Android Open Source Project(AOSP), Google announced in January 2017 that Volley will move to a standalone library. It manages the processing and caching of network requests and it saves developers valuable time from writing the same network call/cache code again and again.

To read more refer to this article: Volley Library in Android

3. What’s a JSON file?

JSON stands for JavaScript Object Notation. It is a text-based data interchange format to maintain the structure of the data. JSON is the replacement of the XML data exchange format in JSON. It is easy to struct the data compare to XML. It supports data structures like arrays and objects and the JSON documents that are rapidly executed on the server. It is also a Language-Independent format that is derived from JavaScript. The official media type for the JSON is application/json and to save those file .json extension.

To read more refer to this article: What’s a JSON file?

4. JSON Parsing in Android using Volley Library

Refer to this article for proper implementation: JSON Parsing in Android using Volley Library

So after learning these important concepts, we will develop an intermediate project this week and the name of the project is “Build COVID-19 Tracker Android App“. 

Project 3: How to Build a COVID-19 Tracker Android App

To build this complete project please refer to this article: How to Build a COVID-19 Tracker Android App. In this article, the complete step-by-step process is explained in detail also we have attached a video to understand the project deeper. 

4th Week

When developers work on a real mobile application whose nature is dynamic and will expand its features according to the user’s need, then it is not possible to write core logic in activities or fragments. To structure the project’s code and to give it a modular design(separated code parts), architecture patterns are applied to separate the concerns. The most popular android architectures used by developers are the following:

1. MVC (Model — View — Controller)
2. MVP (Model — View — Presenter)
3. MVVM (Model — View — ViewModel)

So in the 4th week are going to learn another very important concept i.e Android Architecture Patterns. Please read out the following articles and try to explore as much as you because these concepts are very very useful to become a successful Android Developer. 

• Android Architecture Patterns
• MVC (Model — View — Controller)
• MVP (Model — View — Presenter)
• MVVM (Model — View — ViewModel)

So using these concepts, this week we are going to develop another application “Build a Simple Note App using Android Architecture Pattern”. 

Project 4: Build a Simple Note Android App using MVVM and Room Database in Kotlin

To build this complete project please refer to this article: How to Build a Simple Note Android App using MVVM and Room Database. In this article, the complete step-by-step process is explained in detail also we have attached a video to understand the project deeper. 

5th Week

Firebase! I think you have heard this word. Firebase is a product of Google which helps developers to build, manage, and grow their apps easily. It helps developers to build their apps faster and in a more secure way. No programming is required on the firebase side which makes it easy to use its features more efficiently. It provides services to android, ios, web, and unity. It provides cloud storage. It uses NoSQL for the database for the storage of data. To read more refer to this article: Introduction to Firebase 

Project 5: User Authentication and CRUD Operation with Firebase Realtime Database in Android

So in the 5th week of Android App Development, we are going to explore the Firebase database and how to perform basic authentication and CRUD (Create, Read, Update, Delete) operation with Firebase. To build this complete project please refer to this article: User Authentication and CRUD Operation with Firebase Realtime Database in Android. In this article, the complete step-by-step process is explained in detail also we have attached a video to understand the project deeper. 

You may also refer to this section to know more about Firebase + Android stuff.

6th Week

In the last week of Android App Development, we are going to develop an advanced Android App using multiple advanced concepts. We are going to build a Grocery Android App whose output is like the following.

Project 6: How to Build a Grocery Android App using MVVM and Room Database

So in this project, we are going to build a grocery application in android using android studio. Many times we forget to purchase things that we want to buy, after all, we can’t remember all the items, so with the help of this app, you can note down the grocery items that you are going to purchase, by doing this you can’t forget any items that you want to purchase. A sample image is given below to get an idea about what we are going to do in this article. Note that we are going to implement this project using the Kotlin language. In this project, we are using MVVM (Model View ViewModel) for architectural patterns, Room for database, Coroutines and RecyclerView to display the list of items. 

To build this complete project please refer to this article: How to Build a Grocery Android App using MVVM and Room Database. In this article, the complete step-by-step process is explained in detail also we have attached a video to understand the project deeper. 

Must Refer to the Following Tutorial in Android

• Android Tutorial
• Android Studio Tutorial
• Android Projects Tutorial