Development for the Android operating system opens up enormous opportunities for novice programmers. The mobile application market is growing every year, and the demand for quality products remains consistently high.
Many newcomers mistakenly believe that entering this field requires deep knowledge of mathematics or many years of programming experience. In fact, the entry threshold is much lower than it seems at first glance.
It is enough to have logical thinking, perseverance and a desire to understand new technologies. In this article, we will analyze all the steps necessary to write your first working application and run it on a real device.
Choosing a programming language and preparing the environment
The first step towards creating software is choosing a tool. Historically, the main language for the platform was Java. It is still used in many legacy projects and has a huge documentation base.
However, in 2017, Google officially declared Kotlin the preferred language for development. It is a modern, concise and safe language that allows you to write less code to accomplish the same tasks.
⚠️ Attention: Avoid using outdated tutorials written entirely in Java if you are just starting out. Kotlin's syntax is quite different, and mixing approaches early on can be confusing for a newbie.
You will need an integrated development environment (IDE) to write code. The undisputed leader here is Android Studio. It is free, regularly updated and contains all the necessary tools for emulation, debugging and profiling.
You should download the distribution only from the official website of the developer. Third-party builds may contain malware or be incompatible with the latest versions of the SDK.
If your computer has less than 16 GB of RAM, disable unnecessary plugins in Android Studio immediately after installation. This will speed up the environment and reduce the consumption of system resources.
Installing and configuring Android Studio
The installation process is standard for most operating systems, but requires attention to detail. The installer will automatically offer to download the necessary components, including Android SDK (Software Development Kit) and the emulator.
After the installation is complete, launch the environment and wait until the files are indexed. The first launch may take several minutes as the system downloads the latest updates to Gradle, a tool for building projects.
It is important to correctly configure the virtual device for testing. In the device manager (Device Manager), create a new emulator by selecting the current version of Android and a suitable form factor, for example, Pixel 6 or Galaxy S23.
☑️ Initial environment setup
Make sure that hardware virtualization is enabled in the emulator settings (VT-x for Intel or SVM for AMD). Without this function in the BIOS, the emulator will work extremely slowly or will not start at all.
For those who have a physical device, you must enable developer mode. This is usually done by repeatedly clicking on the build number in the phone settings.
Structure of the first project and navigation
When creating a new project (New Project), the system will prompt you to select a template. To get started, the best template is Empty Views Activity, which creates the minimum necessary structure without unnecessary code.
The environment interface may seem overloaded, but there are only three main areas of work: the code editor, the project panel and the preview window. The project panel displays files in a hierarchical form.
| Folder | Destination | Key files |
|---|---|---|
manifests |
Application configuration | AndroidManifest.xml |
java |
Logic source code | MainActivity.kt |
res |
Resources (pictures, text) | strings.xml, colors.xml |
gradle scripts |
Build settings | build.gradle |
The file AndroidManifest.xml is the passport of your application. It specifies permissions to access the Internet, camera or geolocation, and also records all activities.
The logic of the app resides in files with the extension .kt (for Kotlin). This is where you describe what should happen when buttons are pressed or the screen loads.
Why do we need resources in a separate folder?
Moving texts and colors to the res folder allows you to easily change the interface and support localization (translation into other languages) without editing the app code.
Basics of interface layout (XML and Jetpack Compose)
The appearance of the application is described by markup. The traditional approach uses a language XML, where each interface element (button, text, image) is a tag with its own attributes.
The modern approach, actively promoted by Google, is called Jetpack Compose. It allows you to create interfaces declaratively using only Kotlin code, which makes the layout more flexible and understandable.
Beginners are advised to familiarize themselves with both approaches, since many existing projects still use XML. However, it is more advisable to conduct new projects directly on Compose.
- 📱 LinearLayout —arranges elements in one row or column sequentially.
- 🔲 ConstraintLayout —allows you to position elements relative to each other and screen boundaries.
- 🎨 Material Design —a system of components that provides a unified visual style for applications.
When working with XML It's important to remember different screen sizes. The use of rigid pixel dimensions (px) is prohibited; Always use scaling units dp for sizes and sp for fonts.
⚠️ Attention: The interfaces in Android Studio are constantly updated. Buttons and menus can change locations. If you do not find the described function, use the search by settings (Ctrl+Shift+A).
Writing logic and event processing
After the interface is ready, you need to “revive” it. In the activity file (for example, MainActivity), markup elements are associated with code.
For this, the findViewById mechanism in the old approach or a direct reference to variables in Compose is used. Next, you attach event listeners (OnClickListener) to interactive elements.
An example of the simplest logic: when you click on a button, the text in the text field changes. This is the basic principle of user interaction with the app.
button.setOnClickListener {textView.text = "Hello, Android!"
}
It is important to understand the activity lifecycle (Lifecycle). The application may be minimized, maximized, the screen rotated, or a call may be received. Your app must correctly save state in methods onPause and onResume.
Ignoring the lifecycle will lead to the fact that when the screen is rotated, the user's entered data may disappear, which will create a negative user experience.
Proper handling of the activity lifecycle is the key to stable operation of the application and the absence of crashes when minimizing or rotating the screen.
Testing and debugging the application
Writing code is only half the battle. The second, no less important part is finding and correcting errors. For this purpose, Android Studio has a built-in powerful debugger (Debugger).
You can set breakpoints (breakpoints) at which app execution is suspended. This allows you to check the values of variables in real time and track the execution flow.
Application operation logs are displayed in the panel Logcat. Filtering logs by your application tag helps you quickly find the causes of failures and exceptions (Exceptions).
- 🐞 Use breakpoints for step-by-step code execution.
- 📝 Analyze the call stack (Stack Trace) when the application crashes.
- 📲 Test the application on real devices with different versions OS.
The emulator is convenient for quickly testing logic, but it cannot reproduce all the nuances of working on real hardware. Be sure to check the operation of the sensor, camera and GPS on a physical smartphone before release.
Publishing on Google Play and monetization
When the application is ready, tested and not contains critical errors, the publication stage begins. To publish in the Google Play store, you need to register a developer account.
The registration fee is a one-time fee of $25. After payment, you get access to the developer console, where you can upload APK or AAB files.
Before publishing, you must prepare a high-quality description, screenshots, icon and promotional video. The number of downloads directly depends on the quality of design.
⚠️ Attention: Moderation rules on Google Play strictly regulate content. Applications that violate data privacy or copyright policies will be rejected without a refund.
There are several monetization models: paid downloads, in-app purchases, or advertising through AdMob services. The choice of strategy depends on the type of your product and target audience.
It is also important to comply with the requirements for the target API level (targetSdkVersion). Google regularly increases the minimum requirements, and applications that are not updated to new standards may be removed from the store.
What is an AAB file?
Android App Bundle (AAB) is a new publishing format that allows Google Play to optimize the size of an application for a specific user device, giving away only the necessary resources.
Need to know mathematics for creating applications?
For most standard applications (news, social networks, utilities), basic school mathematics and logic are sufficient. Complex mathematics is required only when developing games, graphic editors or applications for engineering calculations.
Is it possible to develop on a weak computer?
Yes, but with limitations. The emulator may be slow, so it is recommended to use a physical device for USB tests. Disabling heavy plugins and using lightweight versions of the IDE will also help.
How long does it take to create the first application?
A simple business card application or calculator can be made in 1-2 weeks with regular training. More complex database and network projects will require several months of study and practice.
Are training and tools free?
Yes. Android Studio, documentation, emulators, and most of Google's training courses are completely free. You only need to pay for a developer account when publishing to the store.