How to Develop an Android App Using Kotlin: A Complete Guide

Did you know that Android is the leading operating system in mobile app development? Its open-source feature enables developers to download the code just once and modify it according to their needs.

There are numerous options to create an Android app using multiple languages, including Kotlin, Flutter, React Native, Java, and more. It totally depends upon your app requirement whether you choose to create an Android application using Kotlin or any other language.

Over the years, there have been huge updates in Android, and approximately 12 Android versions have been released to date.

Android iOS enables you to develop smooth applications integrated with sophisticated functionalities. While developing an Android application, we have so many things to consider.

If you are still in the process of deciding whether you should develop your first Android application with Kotlin, this tutorial will give you all your answers.

Throughout this guide, we have gone through a detailed step-by-step guide of how to create an Android app using Kotlin and why developers prefer it over Java. You can make a well-informed decision if you are familiar with the benefits of Kotlin for Android app development.

What is the Kotlin Programming Language?

Kotlin is a statically typed, object-oriented language that interoperates with the Java virtual machine (JVM), Java Class Libraries, and Android.

The Kotlin programming language was initially created to enhance the Java programming language and is frequently utilized alongside Java.

Although it is the development language of choice for Android, the interoperability of Kotlin with Java has caused it to be used with a variety of application types.

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What are the Benefits of the Kotlin Language for Android App Development?

Here are some of the major benefits of Kotlin for Android app development:

1. Concise

The prime benefit of Kotlin language compared to other options is that the issues can be resolved by a very minimal amount of code, which is trustworthy with fewer exceptions and bugs.

Uniqueness, such as data classes, smart casts, and type inference, rendered this language short and unique.

2. Complete Java Interoperability

Since Java was the primary language for application development, developing Android applications in any other language apart from Java was a mountain to climb, and this is the primary benefit of Kotlin language, which provided it an edge over the other languages, as it is 100% compatible with Java and developers could easily carry forward their existing Java-based android projects with Kotlin.

3. Easy to Use

Kotlin possesses a highly user-friendly IDE, which enables developers who are engaged with and in other OOP fields to grasp the language in a jiffy and shift to this open-source language without any hassle.

In the domain of app development, animation and the Interactive UI of the application are both the prime characters to make an application a blockbuster in the market, and Kotlin makes it extremely easy and convenient to create and integrate your application with both of these stars.

4. Safer Code

The Kotlin code is less buggy and more accurate. Right from the beginning of app development, it directs the developer's focus toward the possibility of errors and risks, motivating all the developers to eliminate them early and create code with fewer crashes and bugs.

5. Upgrades Over Java

Kotlin gave answers to certain problems of Java, which are:

🔘Null reference control by type system, which is a billion-dollar error in Java

🔘Made arrays invariant

🔘No raw types

🔘No checked exceptions

Kotlin, now the official language for developing Android applications, has numerous advanced peculiarities that provide it with an advantage over other programming languages.

It treats the developers better by providing enhanced support for functional programming and innovative, user-friendly UI.

Kotlin, being completely compatible with Java, enables Java developers to shift their large projects to this language readily. They can incorporate its advanced features into their apps to feel the experience of streamlined and convenient custom mobile app development.

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How to Create an Android App Using Kotlin: Step-by-step Process

Here are the steps that will guide you on how to create an Android app using Kotlin:

Step 0: Install Android Studio

Go to the Android Studio official website and install the integrated development environment. Unlike web development, the whole app development process happens at this one stop.

It has a vast array of app development tools, ranging from the code editor to the emulator used to test the app.

If you are using a 64-bit Windows OS, simply click the Download button; otherwise, click "Download Options" to view Android Studio versions that run on other operating systems.

Step 1: Create a New Android Project & Select the Template

Once installed successfully in it, on opening it, you will have the following welcome screen:

Select the "Start a new Android Project" option from the page. You will be redirected to the "Select a Project Template" page. There are many types of project templates in the Android Studio, like Empty activity, Login activity, Bottom Navigation activity, Map activity, and so on.

You add just a single activity to your project here. Afterward, you can add others using the "New" button from the Android Studio.

When choosing the template, press the Next button for further action.

Step 2: Rename the Application & Select the Language as Kotlin

By default, the app name appears as "MyApplication," and you can change it by modifying the text in the "Name" portion of the "Configure your project" page. The storage path of the Project in your local disk drive can also be changed here.

In the "Configure your project" window, select "Kotlin" under the programming language. If this option does not appear, ensure that you have installed the Kotlin plugin for Android Studio.

Step 3: Create Design Your App Interface

Android Studio includes a drag-and-drop user interface designer known as Layout Editor. Utilize it to design your app's UI. You may also manually edit the XML layout files if you wish.

Below is an example of a simple layout file (activity_main.xml) with a TextView and a Button:

Step 4: Handle Button Click and Display a Toast

In your MainActivity.kt file, you can place the code for handling the button click and show a simple toast message. Here's an example:

Step 5: Write the Kotlin Class code for the App

Once you have created the UI design, you can sync the view object variables using their ID with their Kotlin. Go to the Java folder > Select the package > Write the code in the MainActivity.kt file. To save the existing count, we declare a count variable.

Subsequently, we use two buttons, plus and minus, to increment and decrement the count, respectively.

You need to invoke the setOnClickListeber on the button for performing the increment and decrement operations and the setText method on the TextView to display the value of the existing count.

Shrinking Kotlin libraries & apps with Reflection via R8 is quite easy, read the blog to learn more.

The entire Kotlin Class code for a Counter App:

Step 6: Install the Android Emulator & Test the App

Plug in an Android device or use an emulator, then click on the "Run" button in Android Studio. Your app will be compiled, installed on the device, and run automatically.

Finally! You've just created your first Android app with Kotlin and adopted the best practices for Android development.

We made a basic user interface, responded to button clicks, and showed toast messages. Naturally, this is merely the beginning of Android development, but it gives you a good foundation on which to expand.

As you continue on your path as an Android developer, you'll delve deeper into more advanced subjects such as networking, data storage, and MVVM architecture, as well as working with popular libraries such as Retrofit, Room, and Glide.

Keep learning, browsing the Android developer documentation, and creating engaging apps to hone your skills.

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Kotlin vs. Java: What is the Difference?

Kotlin and Java are statically typed, general-purpose programming languages. Kotlin could be said to be a Java replacement in many ways.

Kotlin is not syntactically compatible but is fully interoperable with Java codebases and libraries. Kotlin also has its own libraries that have been developed with an application programming interface for Android apps.

In Java, redundancy leads to more verbose and lengthy code. Kotlin is easier and thus simple to learn for novice developers. Kotlin emphasizes reduced, functional code and eschews redundant boilerplate code.

Semicolons at the end of each line are unnecessary, even though Kotlin has no problem with their use. Extra features lower the complexity and amount of code necessary to meet the ultimate purpose of a Kotlin team.

An Android app developer may prefer Java to Kotlin if they are a beginner in Android software development. Traditionally, the majority of examples of Android documentation are in Java.

A new developer sorting through these may find it more convenient to interact with them in Java than switching to Kotlin.

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Why do Developers Prefer Kotlin over Java?

The following are some reasons developers prefer Kotlin to Java:

🔘It is brief, with time saved which would otherwise be spent on writing boilerplate code in Java.

🔘You can even translate a Java file into a Kotlin file using just a script.

🔘There is no runtime overhead of Kotlin. In some cases, adding new features to a language results in it having additional overhead, reducing its performance, not with Kotlin.

🔘Kotlin has a big community. If you ever find yourself stuck, you can quickly find other developers to assist you on coding forums and social media platforms.

🔘Kotlin simplifies asynchronous programming. Making network and database calls asynchronously in Java is inept and distressing. Kotlin has coroutines that simplify asynchronous programming and make it efficient.

🔘Kotlin deals with nulls. A Java null will crash your program if you haven't anticipated it. In Kotlin, you can place a straightforward operator on variables that can be null to avoid these crashes.

🔘Kotlin is multiplatform. Kotlin can execute anywhere Java executes, meaning that you can use Kotlin to create cross-platform app development.

🔘Switching to Kotlin is simple. Kotlin is Java's full equivalent, so you will not need to convert all code simultaneously. You can gradually phase in an app to use Kotlin.

Recommended Read: Biggest Challenges Faced in Application Development with their solutions

What Else is Kotlin Used for?

Kotlin is built to be able to run on a Java Virtual Machine and can run alongside Java.

While Kotlin initially began as a language for Android development, it soon gained popularity throughout the Java community due to its characteristics and has now been used for numerous forms of applications.

1. Back-end Web Development

Most of the back-end web development is done in Java, with frameworks such as Spring. However, Kotlin gained a foothold in server-side web development because it was much easier for developers to work with.

The modern features of the language enable Web Developers to build applications that are capable of scaling rapidly on commodity hardware.

As Kotlin is fully interoperable with Java, you can gradually port an application to use Kotlin file by file while the remaining part of the application continues to use Java.

Kotlin also supports Spring and other frameworks, so moving to Kotlin doesn't mean you need to replace everything you are familiar with.

Google, Amazon, and numerous other businesses have already started replacing Java with Kotlin in their server-side applications.

2. Full-stack Web Development

It is logical to implement server-side web development with Kotlin. After all, Java has been in use from the beginning. Nevertheless, it is also possible to utilize Kotlin for front-end development with Kotlin/JS.

Kotlin/JS enables developers to use powerful browser and web APIs in a type-safe manner. Full-Stack Developers need to be familiar with Kotlin alone.

They can develop front-end code in the same language they developed their back-end code, which will be compiled into JavaScript to run within the browser.

3. Data Science

Data Scientists have long employed Java to do number crunching, identify trends, and predict — so naturally, Kotlin would find a home in data science too.

Companies can utilize all the usual Java libraries they employ for Java projects but implement their own code in Kotlin for the data science analytics services.

Jupyter and Zeppelin, tools that are widely utilized on a day-to-day basis by most Data Scientists for data visualization and exploratory analysis, also provide support for Kotlin.

4. Multi-platform Mobile Development

Kotlin is supposed to be a multi-platform software development kit for developing cross-platform mobile applications.

This insinuates that a single kotlin codebase can compile apps that run on more than just Android phones, including iPhones and the Apple Watch. The project is promising despite being in the alpha stage so far.

Conclusion

Developing Android apps using Kotlin is a thrilling experience. This tutorial went through the necessary steps, from initialization to publishing on the Play Store. Keep abreast of trends and best practices for user-centric apps. Now, you are ready to embark on your Kotlin app development journey.

Furthermore, for professional Android app development services, connect with Arramton Infotech. The firm delivers highly scalable, feature-rich mobile applications that are fully customized to your business requirements.

Frequently Asked Questions For Kotlin App Development

Q. Is Kotlin good for Android?

Ans: Yes, Kotlin is fully supported for creating Android applications using Kotlin. We suggest that you use Kotlin to create top-class apps.

Q. How does Kotlin work on Android?

Ans: Kotlin programming language and Java share many similarities. Like Java, Kotlin code is also compiled into Java bytecode and executed by the Java Virtual Machine (JVM). For example, when the Kotlin file Main.kt is compiled, it will ultimately be a class, and then the bytecode of the class is created. The name of the bytecode file will be MainKt.class, and the JVM will execute this file.

Q. Why is Kotlin better than Java for Android?

Ans: Kotlin is much superior to Java in terms of writing your Android programs, as Koltin is a compressed coding language created with additional features that increase the efficacy of your applications.

Q. Why is Kotlin interoperable with Java?

Ans: Kotlin is based on JVM bytecode, making it Java-compatible. It has the facility to directly compile to bytecode, which accelerates compilation time and does not separate Java and Kotlin for the JVM.