Creating a mobile application is exciting a process that opens up endless possibilities for implementing ideas, be it a useful service, a game or a business tool. Many novice developers mistakenly believe that writing code under Android necessarily requires expensive equipment or a specific operating system, but the reality is much more democratic. It is enough to have a modern personal computer running Windows, macOS or Linux to start your journey into the world of mobile development.
You do not need to immediately dive into complex architectural solutions or buy licenses for proprietary software. The industry offers a wide range of free open source tools that allow you not only to write code, but also to test it in a virtual environment directly on the monitor screen. Compilation and debugging of projects occurs locally, which significantly speeds up the development cycle.
In this article we will analyze in detail all stages: from choosing a programming language to publication finished product. You'll learn which tools are the de facto standard, how to set up your work environment, and what pitfalls you might encounter along the way. Whether you want to create a simple calculator utility or a complex social service, the fundamental principles will remain the same.
Selecting tools and development environment
The first and most important step is choice integrated development environment (IDE). This is a software package in which you will write code, debug it, and assemble the final application package. The undisputed leader in this niche is Android Studio, the official environment from Google, built on the basis of the IntelliJ IDEAplatform. It provides the most complete set of tools for working with an integrated development environment. An alternative is a set of plugins if you plan to use cross-platform frameworks such as Flutter or React Native. However, for native development that provides maximum performance and access to all device functions, the classic stack based on SDK (Software Development Kit).
An alternative could be Visual Studio Code with a set of plugins if you plan to use cross-platform frameworks such as Flutter or React Native. However, for native development that provides maximum performance and access to all device functions, a classic stack based on Java or Kotlin in conjunction with Android Studio remains unsurpassed. Installing this software requires a sufficient amount of RAM on the PC, preferably 8 GB, or better yet 16 GB.
In addition to the environment itself, it is critically important to install the correct set of libraries. During the setup process, you will be asked to select the version Android SDK and system images for the emulator. You should not ignore this step, as the lack of necessary components will lead to compilation errors. Modern versions of the IDE have a built-in package manager that will automatically pull up the necessary dependencies.
⚠️ Attention: Android versions are constantly updated. Before starting installation, check the system requirements of the latest stable version of Android Studio on the official developer portal, as the minimum requirements for PC hardware may change with the release of new releases.
Programming languages: Kotlin vs Java
The choice of programming language determines the coding style and available features. For a long time the standard was Java, and many legacy projects are still supported in this language. It has strong typing and a huge documentation base, which makes it understandable for those who already have experience in backend development. However, Java code is often verbose and requires writing a large number of boilerplate constructs.
Since 2019, Google has declared the language Kotlin a priority for Android development. It is a modern, concise and safe language that is fully compatible with Java libraries. Kotlin allows you to write less code to solve the same problems, eliminates a whole class of errors associated with null references, and supports functional programming. For beginners, the entry barrier to Kotlin is often lower due to its more readable syntax.
It is important to understand that both languages are compiled into the same bytecode, which is executed by a virtual machine ART (Android Runtime) on the device. The only difference is how you describe the logic of the application. If you are starting from scratch, it is recommended to immediately focus on Kotlin, as this is an investment in the future of your development career.
- 🚀 Kotlin: Officially supported by Google, less code, protection from runtime errors, excellent compatibility with Java.
- ☕ Java: Huge community, stability, many ready-made solutions and libraries, familiar syntax for many programmers.
- ⚙️ C++: Used via the NDK for high-performance computing, such as gaming or video processing, but difficult to integrate.
Use online Java to Kotlin code converters built into Android Studio to quickly migrate old examples or understand the difference in syntax.
Set up a working environment and emulator
After installing the IDE, you need to configure the virtual device on which your application will run. A physical smartphone is convenient for final testing, but during active development, an emulator is indispensable. It allows you to instantly change device settings, operating system version, and even simulate different geolocations without the need to reconnect cables.
In the device manager (Device Manager) you can create a new virtual gadget. You will be asked to select a form factor (phone, tablet, watch), screen diagonal and resolution. The key point is the choice of the system image (System Image). It is recommended to select images marked Google APIsif your application will use Google services, such as maps or authorization.
To speed up the emulator on a PC with Intel or AMD processors, you need to make sure that virtualization technology is enabled in the BIOS (VT-x or AMD-V). Without this feature, the emulator will work extremely slowly, making the development process unbearable. Modern versions of Android Studio use hypervisors that efficiently use the resources of your processor.
| Component | Minimum requirements | Recommended requirements | Impact on operation |
|---|---|---|---|
| RAM (RAM) | 8 GB | 16 GB and higher | Compilation speed and smoothness of the emulator |
| Storage | HDD | SSD NVMe | Project build time and IDE loading |
| Processor | 4 cores | 6+ cores with virtualization support | Device simulation performance |
| Screen resolution | 1280x800 | 1920x1080 and above | Ease of working with the editor interface |
What to do if the emulator does not start?
If you receive an error related to HAXM or the hypervisor when starting a virtual device, check whether Android Studio conflicts with other virtualization apps such as VirtualBox or Hyper-V. In some cases, you need to disable Hyper-V in Windows components or configure the emulator launch parameters manually.
Project structure and creation of the first interface
When the environment is ready, you can create a new project through the creation wizard (New Project). You will be asked to choose a template: from an empty project (Empty Activity) to applications with bottom navigation or settings. For training, the best template is a basic one that creates the minimum required set of files. The main elements of the structure are folders java (or kotlin) for logic and res for resources.
The application interface is described in XML files located in the directory res/layout. This is where you place visual elements: buttons, text fields, images. Android Studio provides a visual editor that allows you to drag and drop elements with the mouse, but professionals prefer to edit the XML code manually for better control over indentation and attributes. Layout Editor, which allows you to drag and drop elements with the mouse, but professionals prefer to edit the XML code manually for better control over indentation and attributes.
Each interface element has a unique identifier (android:id), through which app code can access it. For example, to change the text on a button when clicked, you need to find this button in the activity code by its ID and call the setText()method. Understanding the relationship between XML markup and logic classes is the foundation of development.
☑️ Structure of the new project
⚠️ Attention: Never rigidly set the sizes of elements in pixels (px). Use scalable units
dp(density-independent pixels) for sizes andspfor fonts, otherwise your application will look incorrect on screens with different pixel densities.
Operation logic and event handling
After the interface is drawn, you need to revive him. The logic of the application is concentrated in the classes of activities (Activities) and fragments (Fragments). An activity is essentially one screen of an application. The activity lifecycle includes methods that are called by the system at certain moments: when created (onCreate), paused, stopped, or destroyed.
User input is processed through event listeners (Listeners). The most common example is installing a button click handler. In code, this looks like assigning a lambda expression or interface implementation to a property onClick. Inside this block, you specify the actions that must be performed: moving to another screen, sending data to the server, or mathematical calculations.
To store data within the application, a mechanism is used SharedPreferences for simple settings or full-fledged databases Room for complex structures. Working with the database should be performed in a separate thread so as not to block the main interface thread, otherwise the application will freeze and the system will throw an error. ANR (Application Not Responding).
- 📱 Activity: The main component representing a separate screen with the user interface.
- 🧩 Fragment: A modular part of the interface that can be used inside an activity to create a flexible design.
- 🔌 Intent: Special a message object used to request an action from another component or transition between screens.
The main rule of multithreading: any long operations (downloading from the network, reading a database) must be performed outside the main UI thread, otherwise the application will be blocked by the system.
Testing, debugging and release build
Writing code is only half the battle. Testing is a critical step. Android Studio has a built-in powerful debugger that allows you to stop app execution at certain lines (breakpoints), view the values of variables in real time, and step through the algorithm. This is an indispensable tool for finding logical errors.
In addition to manual debugging, it is recommended to write automatic tests. Unit tests check the correct operation of individual logic functions, and instrumental tests (UI tests) simulate user actions on the screen. Running tests regularly helps avoid regression, when fixing one bug breaks another part of the application.
When the application is ready for publication, it is necessary to build a release version. To do this, the application signature ( build.gradle . You need to create a signing key (Signing Config) is configured in the configuration filekeystore), which will certify the authorship of the application. Losing the signing key makes it impossible to update an already published application on Google Play, so keep the key file and passwords in a safe place. After signing, a file in the format .apk or .aab (Android App Bundle) is generated, which is uploaded to the store.
What is the difference between APK and AAB?
APK is an installation file ready to run on the device. AAB (Android App Bundle) is a publishing format for Google Play that allows the store to dynamically generate optimized APKs for a specific user's device, reducing the size of the downloaded application.
Is it possible to develop applications without the Internet?
Basic development and coding can be done offline. However, for the initial installation of the SDK, downloading libraries via Gradle and using emulators with Google services, a network connection is required.
How long does it take to create the first application?
A simple business card application or calculator can be created in one evening if you have basic knowledge. More complex projects with database and network queries require several weeks to months of work.
Do you need to know English for development?
Desirable. All documentation, bug reports, and most community professional resources are written in English. Knowledge of technical English will significantly speed up problem solving.