Mobile software development ceased to be the lot of select programmers a few years ago. Today, any enthusiast with a computer and a desire to learn can turn an idea into a working product that will appear on Google Play. Studying how to create a app on Android from scratchopens the door to the world of high technology and potentially profitable business.
The creation process Android applications requires a systematic approach. You have to go from an abstract concept to the compilation of a finished .apk or .aab file. This is an exciting journey that combines creativity, logic and technical skills.
In this article we will analyze all the stages of development, the necessary tools and key decisions that you will have to make. You will learn where to start, what programming language to choose and how to avoid common beginner mistakes to make your first project successful.
Choosing tools and development environment
The foundation of any development is the right environment. For the Android platform, Android Studiohas become the de facto standard. This is the official integrated development environment (IDE) from Google, which includes everything you need: a code editor, device emulator, debugger and profiling tools.
The distribution should be downloaded exclusively from the official website of the developer. Installation on a computer requires a sufficient amount of RAM - at least 8 GB, and preferably 16 GB, since emulators and build processes are quite resource-intensive. After installation, you will need to configure Android SDK (Software Development Kit), which contains libraries and tools for specific system versions.
⚠️ Attention: SDK versions and build tools are constantly updated. The menu interface and option names in Android Studio may vary depending on the version installed. Always check Google's official documentation when searching for a specific setting.
Besides the environment itself, the presence of Java Development Kit (JDK)is critical. Although modern versions of Android Studio often come with a built-in JDK, understanding how the Java runtime works is essential to properly setting up your project. Without a correctly installed JDK, code compilation will be impossible.
For the first installation, select the stable version of Android Studio (Stable Channel), and not Beta or Canary, to avoid unexpected errors and glitches in the environment.
Selecting a programming language and architecture
Before writing the first line of code, you need to decide on the language. For a long time it was the standard, but now Google is actively promoting Java, but now Google is actively promoting Kotlin as the preferred language for Android development. Kotlin has a more concise syntax, Null Safety, and full compatibility with Java.
The choice between these two languages depends on your goals. If you plan to maintain legacy projects or work in large corporations with legacy code, knowledge of Java is a must. For new startups and personal projects Kotlin is the undisputed leader, allowing you to write less code to achieve the same result.
It is also worth mentioning cross-platform solutions such as Flutter (Dart language) or React Native (JavaScript). They allow you to create one application for Android and iOS at once. However, for a deep understanding of how to create a native Android application from scratch, it is better to start with Kotlin or Java.
- 🚀 Kotlin: Modern, secure, Google's preferred choice for new projects.
- ☕ Java: A classic language with a huge knowledge base and libraries, ideal for supporting legacy code.
- 🎨 C++: Used via NDK for high-performance tasks such as games or video processing.
- 🌐 Dart/JS: Options for cross-platform development if you need to cover iOS as well.
Creating the first project and file structure
Launching Android Studio and creating a new project is a ritual with which the life of any application begins. When choosing a template for beginners, Empty Activityis optimal. This template creates the minimum necessary structure, not overloaded with unnecessary components, which allows you to understand the basics.
In the project settings window, you need to specify the name of the application (Application Name), package (Package Name) and programming language. A package is a unique identifier for your application in domain name format, for example com.example.myapp. It is extremely difficult to change it after creating a project, so choose the name carefully.
The most important parameter is Minimum SDK. This is the minimum version of Android that your app will run on. The lower you set this value, the more devices will be able to install your application, but the fewer modern system features you will have access to. The golden mean for modern projects is Android 5.0 (API 21) or higher.
android {compileSdk 34
defaultConfig {
applicationId "com.example.firstapp"
minSdk 24
targetSdk 34
versionCode 1
versionName "1.0"
}
}
After creation, you will see the project structure. Main folders: java (or kotlin) contains the logic of work, and the folder res stores resources: screen layouts (layout), images (drawable), lines of text (values/strings.xml). Separation of code and resources is a key principle of the Android architecture.
☑️ Checking the settings of the new project
User interface design
The appearance of the application is described in XML files located in the directory res/layout. The traditional approach uses hierarchy ViewGroups i Views. You place buttons, text fields and images on a virtual canvas, setting their properties through attributes.
A declarative UI framework is becoming the modern standard. Jetpack Compose. It allows you to draw the interface directly in Kotlin, without using XML. This speeds up development, makes the code more readable, and makes it easy to create complex animations. However, the classic XML approach is still widely used in existing projects.
When designing a layout, it is critical to consider adaptability. Smartphone screens have different diagonals and pixel densities (dp). The use of fixed pixel dimensions is prohibited. Instead, relative units and flexible containers, such as ConstraintLayout, are used, which allow elements to adapt to screen size.
| UI Element | Description | Typical Usage |
|---|---|---|
TextView |
Display text | Headings, descriptions, labels |
Button |
Interactive button | User actions (Submit, Login) |
EditText |
Text input field | Registration forms, search strings |
ImageView |
Display graphics | Logos, photographs, icons |
RecyclerView |
Scrolling list | News feeds, contact lists |
⚠️ Attention: Never use absolute coordinates to place elements. What looks beautiful on the Pixel 6 emulator may look completely different on a Samsung or Xiaomi screen with a different aspect ratio.
Writing logic and working with data
An interface without functionality is just a picture. The "brain" of the application resides in classes called Activities or Fragments. This is where you describe the app’s response to user actions: button presses, swipes, data input.
To store data within the application, it is most often used SQLite through abstraction Room Database. This is a powerful library that simplifies working with the database, allowing you to save information even after closing the application. For simple settings, SharedPreferences (or DataStore) is suitable, and for complex network requests - the library Retrofit.
It is important to remember about the Main Thread. Any heavy operations, such as Internet queries or database reading, must be executed in background threads. If you block the main thread with a long-running operation, the system will consider the application to be hung and show the user an error ANR (Application Not Responding).
What is the life cycle of an Activity?
An Activity goes through several states: Created, Started, Resumed, Paused, Stopped, Destroyed. Understanding these states is critical to saving data when rotating the screen or minimizing the application, otherwise the user will lose the entered information.
Testing and debugging the application
Writing code is only half the battle. The second half is finding and correcting errors. Android Studio has a built-in powerful debugger (Debugger), which allows you to execute code line by line, check the values of variables in real time and analyze the call stack.
You can test the application on a real device or on an emulator. Connecting a real smartphone requires turning on the mode USB debugging in the developer menu on the phone itself. The emulator is convenient because it allows you to quickly test an application on different versions of Android and with different screen characteristics without the presence of physical devices.
To automate code quality checks, tools Lint and unit tests (Unit Tests) are used. They help find potential bugs before the application is launched. Regular testing on different screen resolutions and OS versions guarantees stable operation of the app for end users.
Regular testing on real devices is mandatory, since emulators do not always correctly reproduce the operation of the camera, GPS and motion sensors.
Building and publishing on Google Play
When the application is ready, The stage of assembling the release version begins. To publish on the Google Play Store, you need to generate a file in the format .aab (Android App Bundle), which replaced the outdated .apk. This format allows the store to optimize the size of the downloaded file for a specific user device.
The critical moment is the creation Keystore (signature key). This digital certificate confirms the authorship of the application. Losing the key file means you will not be able to update your application in the future, so its backup copy should be stored in the most secure place.
Before publishing, you need to fill out the application card in the Google Play Console: upload screenshots, icon, description and privacy policy. The moderation process can take from several hours to several days. Once approved, the application will be available for download by millions of users.
How much does it cost to publish an application on Google Play?
To create a developer account, a one-time registration fee of $25 is required. After that, publishing an unlimited number of apps is free, but Google retains a commission on in-app purchases and paid downloads.
Is it possible to create an Android app without programming?
Yes, there are application builders (No-Code platforms), such as AppSheet or Thunkable. They allow you to assemble simple applications from ready-made blocks. However, to create a complex, unique and productive product, knowledge of code is required.
Which version of Android is better to choose as the minimum (MinSDK)?
It is recommended to install MinSDK no lower than API 24 (Android 7.0). This covers more than 90% of active devices, while allowing you to take advantage of modern security and design features without wasting resources on maintaining legacy systems.
What is the difference between an APK and an AAB?
APK is a ready-made installation file containing resources for all screens and languages. AAB (Android App Bundle) is a set of modules from which Google Play collects an optimized APK specifically for the user's device, reducing the download size.