In the modern digital world, having your own mobile application has become not just a trend, but a necessity for business and an excellent start for a developer’s career. However, having seen endless lists of technologies, frameworks and programming languages, a beginner is often at a loss: which path to choose and where to find reliable information?
Development under Android opens up enormous opportunities, since this operating system occupies more than 70% of the global smartphone market. To create a quality product, you don't need to be a math genius, but you will need perseverance, logical thinking and a desire to constantly learn as technology is updated at an incredible rate.
In this article, we will look at the fundamental steps you need to take to transform from an ordinary smartphone user to a software creator. You will learn what tools you will need, how to set up a working environment and write your first code.
Choosing a programming language and technology
The first and most important question that a novice developer has is what to write in? For a long time, the de facto standard was the language Javain which the Android kernel and millions of applications are written. It is reliable, has a huge documentation base and is time-tested.
However, in 2019, Google announced the transition to Kotlin as the preferred language for Android development. Kotlin is fully compatible with Java, but has a more concise syntax, allowing you to write less code and avoid common mistakes such as Is it worth learning Java today? If you plan to support old projects or work at large banks with legacy code, yes. But for starting from scratch in 2026, Kotlin is definitely recommended. NullPointerException.
Is it worth learning Java today? If you plan to support old projects or work at large banks with legacy code, yes. But for starting from scratch in 2026, Kotlin is definitely recommended.
In addition to native languages, there are cross-platform solutions that allow you to write code once and run it on both Android and iOS. The most popular are Flutter (Dart language) and React Native (JavaScript). They simplify development, but may be inferior in performance to complex native applications.
⚠️ Attention: Do not try to learn all the technologies at once. Choose one main stack (for example, Kotlin + Jetpack Compose) and go deeper into it, otherwise you risk being left with superficial knowledge that is insufficient to create a real product.
Installing and configuring the development environment
For comfortable work, you will need a specialized app — IDE (Integrated Development Environment). For Android development, the standard is Android Studio, created based on IntelliJ IDEA. It provides all the necessary tools: a code editor, a device emulator, a debugger and a profiler.
The installation process is quite simple, but requires attention to system requirements. Android Studio is a resource-intensive application, so for it to run smoothly, it is advisable to have at least 16 GB of RAM and an SSD drive. On older HDDs, installation and compilation of projects can take an unreasonably long time.
After installing the IDE, you need to configure Android SDK (Software Development Kit). It is a set of libraries and tools that allow your code to interact with the operating system. In the SDK manager you can download the necessary platform versions, build tools and system images for the emulator.
An important step is creating a virtual device (AVD —Android Virtual Device). The emulator allows you to test the application on your computer without the need to connect a physical smartphone. You can create profiles for different devices with different screen resolutions and Android versions.
☑️ Preparing the workplace
⚠️ Attention: Versions of tools and libraries in Android Studio are frequently updated. The menu interface or item names may differ slightly from the screenshots in old tutorials. Always check the official documentation if you can't find the setting you need.
Architecture basics and project structure
When you create a new project in Android Studio, a standard folder and file structure is generated. Understanding what each of them is responsible for is critical for further work. The basis of the project is manifest files, Kotlin/Java code and resources.
The file AndroidManifest.xml is the passport of your application. It specifies permissions to access the camera, the Internet or geolocation, and also registers all the screens (Activities) that make up the application. An error in the manifest often results in the application simply not starting.
The app code is usually located in the java or kotlindirectory. Here are classes that describe the logic of work. Resources (pictures, texts, styles, screen layouts) are stored in the folder res. This separation allows you to easily change the design or translate the application into other languages without affecting the app code.
Modern development follows the architecture MVVM (Model-View-ViewModel) or MVI. This helps to divide responsibility: one part of the code is responsible for the data, another for display on the screen, and a third for the interaction logic. This approach makes the code maintainable and understandable.
| Component | Purpose | Location |
|---|---|---|
| Activity | Responsible for one screen with the interface | java/kotlin |
| Fragment | Part of the interface inside the Activity | java/kotlin |
| Layout (XML) | Visual markup of elements | res/layout |
| Manifest | Configuration and access rights | manifests |
| Gradle | Project assembly scripts | root/app |
Creating the first interface
The user interface (UI) is what a person interacts with. Traditionally, interfaces in Android were described in language XML. You drag buttons and text fields in the visual editor, and the system generates markup code.
However, in recent years, Google has been actively promoting the technology Jetpack Compose. This is a modern toolkit for creating native interfaces using Kotlin code. Compose allows you to create complex animations and responsive layouts much faster than classic XML.
For a beginner, choosing between XML and Compose can be difficult. XML is still widely used in existing projects, so knowing its basics is useful. But for new projects, especially if you are learning from scratch, Jetpack Compose is the most promising and recommended choice..
When designing the interface, it is important to remember the variety of Android smartphone screens. Your application should display correctly on both compact phones and large tablets. Using flexible layouts (in XML or Compose) solves this problem. Use the Preview tool in Android Studio to instantly see changes to the interface without launching the emulator. This significantly speeds up the layout process.ConstraintLayout in XML or Row/Column in Compose) solves this problem.
Use the Preview tool in Android Studio to instantly see changes to the interface without launching the emulator. This significantly speeds up the layout process.
Operation logic and event processing
A beautiful picture without funcionalnosti is useless. The next stage is revitalizing the interface. You need to teach the application to respond to user actions: button presses, text input, swipes.
In the Android world, all actions are tied to life cycle (Lifecycle) components. An Activity or Fragment goes through the states: creation (onCreate), start (onStart), pause (onPause) and destruction. Understanding these states is necessary in order, for example, to save data when the user minimizes the application.
To work with data and perform heavy operations (downloading from the Internet, working with a database), you cannot use the main thread (UI Thread), otherwise the application will freeze. For this, coroutines (Coroutines) in Kotlin or asynchronous threads are used.
An example of a simple button click handler in Kotlin:
button.setOnClickListener {val text = editText.text.toString()
textView.text = "Hello, $text!"
}
This code shows how to bind visual element with logic. But in a real application, you will also have to handle network errors, save data to a local database Room and work with APIs of third-party services.
⚠️ Attention: Never perform long operations (network requests, reading large files) in the main interface thread. This will cause an error
NetworkOnMainThreadExceptionand the application will crash.
Testing and publishing the application
Writing code is only half the battle. The application needs to be tested on real devices, since the emulator cannot reproduce all the nuances of the hardware, for example, the rate of battery discharge or the operation of sensors.
There are two main types of testing: manual (you click all the buttons yourself) and automated (writing scripts that check the operation of the application). The tool Espresso allows you to write tests that simulate user actions.
When the application is ready, you need to sign it with the developer’s digital key and generate an installation file. Previously, the format was used .apk, but now Google Play requires the format .aab (Android App Bundle), which allows you to optimize the size of the application for a specific user device.
Publishing in the Google Play Console requires payment of a one-time registration fee ($25). After downloading the application, it undergoes moderation, which can take from several hours to several days. Rejection is possible due to violation of security or content policies.
What to do if the application is rejected?
Carefully study the letter from the Google Play team. Usually a specific reason is indicated there: a violation of intellectual property rights, a request for unnecessary permissions, or unstable operation. Correct the error and submit the build for re-review.
Regular app updates and responding to user reviews on Google Play are critical to promoting and retaining your audience.
Frequently asked questions by beginning developers
Do you need to know mathematics to develop applications?
For most standard applications (shops, news, social networks) the school curriculum and developed logical thinking are enough. Higher mathematics is only required when developing games, graphics applications, or complex financial algorithms.
How long does it take to learn how to create applications?
Basic skills to create a simple application can be mastered in 2-3 months of intensive training. However, becoming a professional capable of working in a team on complex projects takes 1 to 2 years of constant practice.
Can you develop on Android using Mac or Linux?
Yes, Android Studio works great on all three major operating systems: Windows, macOS and Linux. Moreover, to publish applications in the App Store (iOS), having a Mac computer is a prerequisite.
Where to get ideas for your first projects?
It is best to start by copying existing simple applications: calculator, To-Do list, weather forecast. This will help you understand the structure without wasting time coming up with a unique idea.