Creating your first Android application: from idea to publication

Developing mobile applications for Android may seem like a daunting task, especially if you have never programmed before. However, modern tools greatly simplify this process. With the advent of Android Studio and language Kotlin (which is now preferred for Android development), even a beginner can create a simple application - just follow clear instructions and not be afraid to experiment.

In this article we will look at the whole path: from installing the necessary software to loading the finished application into Google Play Console. You will learn what tools are required, how to set up the first sandbox for testing, and what basic interface elements can be added to the application at the start. And most importantly, we will avoid unnecessary theory and focus on practice, so that you can see the result after just a couple of hours of work.

Even if you do not plan to become a professional developer, the ability to create simple utilities for your own needs (for example, a notepad, a timer or a currency converter) can save time and money. Plus, it's a great way to understand how the apps you use every day work.

1. Preparation: what you need to develop Android applications

Before you start writing code, you need to install and configure the working environment. Without this step, further development is simply impossible. Here is the minimum set of tools:

• 🖥️ Computer with an operating system Windows 10/11, macOS or Linux (recommended at least 8 GB of RAM and 20 GB of free disk space).
• 📱 Android device for testing (optional, but desirable; suitable smartphone Android 8.0+).
• 🔧 Android Studio —official development environment from Google (free).
• 📡 Stable Internet connection for downloading SDK and updates.

The most important element here — Android Studio. This is not just a code editor, but a full-fledged set of tools, including:

• 🛠️ Built-in Android emulator for testing without a physical device.
• 📦 SDK Manager for managing Android versions and libraries.
• 🔍 Profiler for analyzing application performance.
• 📝 Visual layout editor (for creating interfaces without manual code).

Download Android Studio can c official website. Make sure you choose a version that is compatible with your operating system. Installation takes from 10 to 30 minutes depending on the Internet speed and PC performance.

⚠️ Attention: If you are using macOS, check that you have the latest version installed Xcode (via App Store). This will be required for the emulator to work correctly.

2. Installing Android Studio and setting up the first project

After downloading Android Studio run the installer and follow the instructions on the screen. The process is standard: select components to install (it is recommended to leave everything by default), specify the path and wait for completion. When you first start the app, you will be prompted to download additional components - agree, this is necessary for work.

Now let's create the first project:

1. In the start window Android Studio select New Project.
2. In the list of templates, select Empty Activity (this is the minimum required set of files for a simple application).
3. Set the application name (for example, MyFirstApp), select the language Kotlin and the minimum SDK version (recommended API 21: Android 5.0 Lollipop for maximum compatibility).
4. Click Finish and wait until the environment generates the project.

After a few minutes you will see the project structure in the left panel. The main files to work with:

• 📄 MainActivity.kt — the main screen of the application (logic on Kotlin).
• 🎨 activity_main.xml — interface markup file (what and where is displayed on the screen).
• 📦 AndroidManifest.xml — configuration file with application metadata.

Before starting the project, make sure that the device for emulation (or a real smartphone is connected in debugging mode). To do this:

1. Enable on the smartphone Developer mode (usually in Settings → About phone → Build number - press 7 times).
2. Activate USB debugging in the developer menu.
3. Connect the device to the PC and confirm trust in the computer on the smartphone screen.

3. Getting to know Android Studio's interface may seem overwhelming, but it's actually organized logically. Let's look at the key elements:

Interface Android Studio may seem overwhelming, but it's actually organized logically. Let's look at the key elements:

Area	Purpose	Where is
Project View	Project file tree. Here you see all the folders and resources (code, images, layouts).	Left panel (default)
Editor	The main workspace for editing code and XML markup.	Central part
Build Output	Project build logs. Errors and warnings are displayed here.	Bottom panel (tab Build)
Device Manager	Manage emulators and connected devices.	Upper right icon (📱)

One of the most useful tools - visual layout editor. Open the file activity_main.xml and switch to the tab Design at the top of the editor. Here you can drag interface elements (buttons, text fields, images) with the mouse, and Android Studio automatically generate the corresponding XML code.

For example, to add a button:

1. In the component palette (Palette) find Button.
2. Drag it to the layout.
3. In the right panel (Attributes) set the text of the button (for example, Click me!) and other parameters.

After this, code like this will appear in the file activity_main.xml data-i="136">android:text="Click me!" />

<Button
android:id="@+id/myButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Press me!" />

4. We write the first code: processing a button click

Now let's move on to programming the logic. Open the file MainActivity.kt —here we will write code in Kotlin. Our task: to make sure that when you click on the button, a message appears on the screen.

Here are step-by-step guide:

1. Find the line setContentView(R.layout.activity_main) —it connects our code with the layout.
2. Under it, add code to search for the button by ID and assign a handler clicks:

val myButton: Button = findViewById(R.id.myButton)
myButton.setOnClickListener {
Toast.makeText(this, "Hello, Android!", Toast.LENGTH_SHORT).show()
}

Let's look at what's happening here:

• 🔍 findViewById(R.id.myButton) — finds the button in the layout by identifier myButton (which we set in XML).
• 📱 setOnClickListener —assigns an action when pressed.
• 💬 Toast.makeText —shows a short pop-up message.

Launch the application (green button Run or Shift+F10). If everything is done correctly, when you click on the button you will see the message "Hello, Android!".

⚠️ Attention: If you see an error when building the project Unresolved referencecheck whether the necessary classes are imported at the beginning of the file. Android Studio usually prompts which imports need to be added (click Alt+Enter on the underlined code).

What is Toast in Android?

Toast (translated as “toast”) is a small pop-up notification that appears on top of the interface and disappears after a few seconds. It does not block interaction with the application and is usually used to show short messages to the user (for example, “Saved” or “Input error”).

5. Testing and debugging the application

Testing is a mandatory stage of development. Even in a simple application, errors can occur that are not always noticeable at first glance. Here are the main testing methods:

• 🖥️ Android emulator —a virtual device that simulates a real smartphone. Plus: no physical device required. Disadvantage: it can work slowly on weak PCs.
• 📱 Real device is the most accurate method, since the features of a specific model are taken into account. Requires enabling developer mode.
• 🔧 Unit tests —automated tests for checking individual parts of the code (advanced level).

To create an emulator:

1. Open Device Manager (icon 📱 in the upper right corner).
2. Click Create Device and select the model (for example, Pixel 5).
3. Download the system image (recommended Android 12.0 or newer).
4. Start the emulator and wait for it to load.

During testing, monitor the logs in the tab Logcat (bottom panel) All application events are displayed here, including errors. For example, if your application closes suddenly, you will see Exception with a description of the problem.

Typical mistakes of beginners:

• 🚫 NullPointerException - attempt to access a non-existent element (for example, you forgot to call findViewById).
• 🔄 ClassCastException - incorrect type casting (for example, trying to assign a text field to a type variable Button).
• 📱 ActivityNotFoundException - missing declaration activity in AndroidManifest.xml.

6. Adding functionality: an example with an input field

Let's look at a more complex example: an application that greets the user by name. you will need:

1. Text entry field (EditText).
2. Submit button.
3. Text field for displaying the result (TextView).

Modify first activity_main.xml:

<EditText
android:id="@+id/nameInput"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter your name" />

<Button
android:id="@+id/greetButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Welcome" />

<TextView
android:id="@+id/greetingText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp" />

Now update the logic in MainActivity.kt:

val nameInput: EditText = findViewById(R.id.nameInput)
val greetButton: Button = findViewById(R.id.greetButton)
val greetingText: TextView = findViewById(R.id.greetingText)

greetButton.setOnClickListener {
val name = nameInput.text.toString()
if (name.isNotEmpty()) {
greetingText.text = "Hello, $name!"
} else {
Toast.makeText(this, "Please enter a name", Toast.LENGTH_SHORT).show()
}
}

Here we are:

• 📝 We get the text from the input field using nameInput.text.toString().
• 🔍 We check if the field is empty (isNotEmpty()).
• 💬 We update the text field or show Toastif the name is not entered.

This example demonstrates the basic principles of interacting with the interface: reading user input, processing events and dynamically updating content.

7. Preparing for publication on Google Play

If you have brought the application to a working state and want to share it with others, the next step is publishing it on Google Play. you will need:

• 💰 Registration fee - $25 (one-time).
• 📝 Developer account in Google Play Console.
• 📦 Signed APK/AAB file (build for release).
• 🎨 Graphic materials (icon, screenshots, banners).

Build preparation process:

1. B Android Studio select Build → Generate Signed Bundle / APK.
2. Select Android App Bundle (.aab) (recommended format for Google Play).
3. Create a new signing key (or use an existing one). Keep this key in a safe place - without it you will not be able to update the application!
4. Fill out the version information and wait until the build is complete.

After that:

1. Download .aab-file in Google Play Console.
2. Fill in the metadata: title, description, category, age restrictions.
3. Add screenshots (requirements: 1920×1080 pixels, at least 2 pieces).
4. Specify price (free or paid) and countries of distribution.
5. Submit for moderation (usually takes 1-3 days).

⚠️ Attention: Rules Google Play are regularly updated. Before publishing, check the current content requirements, especially if your application works with personal user data or contains advertising.

8. Alternative ways to create Android applications

If Android Studio i Kotlin seem too complicated, there are simpler tools for creating applications without deep programming knowledge:

Platform	Features	Suitable for
MIT App Inventor	Visual designer from MIT. Programming using blocks (as in Scratch).	Simple utilities, educational projects
Thunkable	Cloud service with drag-and-drop interface. Export to APK.	Prototypes, MVP, applications for small businesses
Flutter	Google framework for cross-platform development (Android + iOS). Uses the Dart language.	Applications with complex UI, startups
Kodular	An analogue of App Inventor with advanced capabilities (for example, working with Firebase).	Games, applications with a database

These tools allow you to create a working application in a few hours, but have limitations:

• ⚠️ It is impossible to implement complex logic (for example, video processing or machine learning).
• ⚠️ Pre-made templates may look “non-native” on some devices.
• ⚠️ A paid subscription is often required to remove watermarks or export.

However, for first experiments or simple tasks (for example, an application for maintaining a shopping list), they can be an excellent starting platform.

FAQ: Frequently asked questions about creating Android applications

Do you need to know Java to develop for Android?

No, not necessarily. Kotlin is the officially recommended language for Android development since 2019. It is compatible with Java, but more modern and concise. However, knowledge of Java can be useful for supporting legacy projects or reading someone else's code.

Is it possible to develop Android applications on a smartphone?

Technically, yes, but it is extremely inconvenient. There are applications like AIDE or Dcoderthat allow you to write code on your phone, but serious development requires a computer. You can’t run an Android emulator on a smartphone, and it doesn’t have enough performance to build projects.

How long does it take to create a simple application?

If you follow this guide, a basic application with one button can be assembled in 1-2 hours. More complex projects (for example, with a database or network queries) may require several days or weeks, depending on experience.

Do you need to pay to publish on Google Play?

Yes, registering a developer account costs $25 (one-time). This is a prerequisite for downloading applications. Alternative stores (for example APKMirror or Amazon Appstore) may have different tariffs.

Is it possible to make money on free applications?

Yes, there are several ways to monetize:

• 📢 Advertising (via AdMob or other networks).
• 💎 In-app purchases (for example, premium features).
• 📊 Affiliate apps (referral links).
• 🤝 Sponsorship (if the application is gaining popularity).

However, please note that Google Play takes a commission 15–30% on transactions.