How to create a app on Android: from idea to publication on Google Play

Creating your own application for Android is a task that seems difficult only at first glance. In fact, even without programming experience, you can develop a functional mobile application if you follow a clear algorithm and use modern tools. Today the platform Android occupies more than 70% of the global mobile OS market, which makes it an ideal platform for implementing your ideas - be it a utility, a game or a business project.

In this guide we will analyze the entire process: from preparing a working environment to publishing the finished product in Google Play. You will learn which programming languages ​​are suitable for beginners, how to work with Android Studio (the official development environment from Google), and what pitfalls may be encountered along the way. And if you’ve never written code before, it doesn’t matter: we’ll tell you where to start and how not to abandon the project halfway through.

1. Selecting tools and preparing the workplace

Before you start writing code, you need to set up the environment. The main tool for development under Android is Android Studio, a free IDE from Google, which includes everything you need: a code editor, device emulator, debugger and even project templates. You can download it from official website (choose version Android Studio Giraffe or newer).

Minimum system requirements for comfortable work:

• 🖥️ Operating system: Windows 8/10/11 (64-bit), macOS 10.14 or newer Linux (distributions based on GNU C Library 2.31)
• 💾 RAM: minimum 8 GB (recommended 16 GB for working with the emulator)
• 💿 Disk space: no less 4 GB for itself Android Studio + 1–2 GB for SDK and cache
• 🖱️ Additional: a mouse with a wheel (will speed up navigation through the code) and a monitor with a resolution no lower 1280×800

After installation Android Studio run it and wait until the initial setup of the System is completed automatically. will download the latest versions of Android SDK (set of development tools) and emulator. If you have a weak computer, you can save resources by installing only the necessary components:

Component	Purpose	Do beginners need it?
Android SDK Platform	Basic libraries for building applications	✅ Yes
Android Emulator	Virtual device for testing	✅ Yes (but you can use a physical smartphone)
Google Play services	Integration with services Google (cards, authorization, etc.)	⚠️ Only if you plan to use them
NDK (Native Development Kit)	Development for C/C++ for high-performance tasks	❌ No (not relevant for beginners)

⚠️ Attention: If you are working on macOS with a chip Apple Silicon (M1/M2), install the version Android Studio marked Apple Chip. Otherwise, the emulator may not start.

2. Choosing a programming language: what to learn in 2026?

Several languages ​​are available for software development, and the choice depends on your goals and experience. Here are the main options: Android Several languages ​​are available, and the choice depends on your goals and experience. Here are the main options:

• 📱 Kotlin - officially recommended Google language since 2019. The syntax is more concise than that of Java, less “template” code, better support for modern features (coroutines, extensions). Ideal for beginners.
• ☕ Java - a classic, most existing applications are written on it. More strict and verbose, but still in demand (especially in legacy projects).
• 🌐 Flutter (Dart) - framework from Google for cross-platform development (one application for Android and iOS). Suitable if you plan to release on both platforms.
• 🛠️ C# (Xamarin) —an alternative for those who are familiar with the ecosystem Microsoft. Less popular, but allows you to use .NET libraries.

For the first project we recommend Kotlin - it is easier to learn and is actively being developed. Example code for Kotlin to display a message:

// Main function (application entry point)
fun main() {
println("Hello, Android!") // Outputs text to the console
}

Important: from August 1, 2023, all new applications on Google Play must support 64-bit architecture (ARM64 or x86_64). This is automatically provided when using Kotlin/Java in Android Studio, but if you are working with native code (C/C++), check your build settings.

3. Creating the first project in Android Studio

Now let's move on to practice. Run Android Studio and follow these steps:

1. Click New Project → select a template Empty Activity (this is a minimal working project with one screen).
2. Give a name to the application (for example, MyFirstApp), select language (Kotlin or Java) and minimum version Android (recommended API 24: Android 7.0 for wide compatibility).
3. Click Finish — the studio will generate the base code and markup.

The project structure Android Studio includes key folders:

• 📁 app/src/main/java — source code Kotlin/Java.
• 📁 app/src/main/res — resources (screen layout, icons, lines text).
• 📄 app/build.gradle — build configuration (SDK version, dependencies).
• 📄 AndroidManifest.xml — application manifest (permissions, activities).

Open the file activity_main.xml (home screen layout) and add a button:

<Button
android:id="@+id/myButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Press me!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />

Then in the file MainActivity.kt (or MainActivity.java) add a click handler:

// Kotlin
myButton.setOnClickListener {
Toast.makeText(this, "Hello from Android!", Toast.LENGTH_SHORT).show()
}

Install Android Studio|Create a project with the Empty Activity template|Add a button to activity_main.xml|Write a click handler in MainActivity|Connect a physical device or configure an emulator-->

4. Testing the application: emulator vs real device

Before publication, the application needs to be tested. You have two options:

1. Android emulator —a virtual device that runs on your computer. Pros: no additional equipment needed, you can simulate different versions Android and screen resolutions. Cons: slows down on weak PCs and does not always accurately reproduce the behavior of a real device.

To create an emulator:

1. In Android Studio open Tools → Device Manager.
2. Click Create Device → select the model (for example, Pixel 5).
3. Download system image (we recommend Android 13 or Android 14).
4. Start the emulator and wait for it to load.

2. Real device is a more reliable method, since you see how the application works on the hardware. To do this:

• 🔌 Enable USB debugging on your smartphone: Settings → About phone → Build number (press 7 times to activate developer mode), then Settings → System → For developers → USB debugging.
• 🖥️ Connect the phone to the computer via USB and confirm trust in the device.
• 🔄 In Android Studio select your device in the drop-down menu and click Run.

⚠️ Attention: On some devices (for example, Xiaomi or Huawei), you additionally need to enable the option Installation via USB in the developer settings Without this Android Studio will not be able to install the application.

5. Interface design: from prototype to adaptive layout

A good interface is the key to the success of the application:

1. Prototyping. Before writing code, draw screen layouts on paper or in special tools:

- Figma (free for personal use),

- Adobe XD,

- Canva (templates for mobile applications are available).

2. Markup in XML. The Android interface is described in files .xml (folder res/layout). Main elements:

• 📱 ConstraintLayout —a flexible container for placing elements (recommended for beginners).
• 📝 TextView —text display.
• 🖼️ ImageView —image output.
• 🔘 Button, Switch, Checkbox —interactive elements.

An example of adaptive markup using ConstraintLayout:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Welcome!"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>

<Button
android:id="@+id/enterButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Login"
app:layout_constraintTop_toBottomOf="@id/title"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

3. Styles and themes. To avoid duplicating the design, use styles in the file res/values/styles.xml:

<style name="MyButtonStyle" parent="Widget.Material3.Button">
<item name="android:backgroundTint">@color/purple_500</item>
<item name="android:textColor">@android:color/white</item>
<item name="android:padding">12dp</item>
</style>

⚠️ Attention: Since 2023 Google recommends using the library Material Design 3 (com.google.android.material:material:1.9.0) for modern design. Older versions Material Components (1.6.0 and below) may not support new features, for example, dynamic theming.

How to check the adaptability of markup?

Q Android Studio open the markup file (activity_main.xml) and select Designin the upper right corner. In the preview panel, you can change the screen size, orientation, and even simulate different devices (for example, Galaxy Fold to test on folding smartphones).

6. Adding functionality: working with data and API

A static application with one button is good, but let's add dynamics. Let's consider two scenarios:

1 is suitable. Local data storage. For simple data (settings, cache) SharedPreferences:

// Saving data
val sharedPref = getSharedPreferences("myPrefs", Context.MODE_PRIVATE)
with(sharedPref.edit()) {
putString("username", "user123")
apply()
}

// Reading data
val username = sharedPref.getString("username", "default_value")

For structured data, use Room (library for working with SQLite):

// 1. Add a dependency to build.gradle:
implementation "androidx.room:room-runtime:2.5.2"
annotationProcessor "androidx.room:room-compiler:2.5.2"

// 2. Create an entity (model data):
@Entity
data class User(
@PrimaryKey val id: Int,
val name: String
)

// 3. Create a DAO (interface for requests):
@Dao
interface UserDao {
@Query("SELECT * FROM user")
fun getAll(): List<User>

@Insert
fun insert(user: User)
}

2. Working with network APIs. To interact with the server, use Retrofit:

// 1. Add dependencies:
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'

// 2. Create an interface for the API:
interface ApiService {
@GET("users/{id}")
suspend fun getUser(@Path("id") userId: Int): Response<User>
}

// 3. Initialize Retrofit:
val retrofit = Retrofit.Builder()
.baseUrl("https://api.example.com/")
.addConverterFactory(GsonConverterFactory.create())
.build()

val api = retrofit.create(ApiService::class.java)

Don't forget about permissions in the manifest! To work with the Internet, add:

<uses-permission android:name="android.permission.INTERNET" />

7. Optimization and preparation for publication

Before releasing the application in Google Play complete the required steps:

1. Performance optimization:

• 🔍 Check the application for memory leaks using Android Profiler (built into Android Studio).
• 🗑️ Reduce APK size: remove unnecessary resources, use WebP instead of PNG/JPG for images.
• ⚡ Enable ProGuard (in build.gradle) to reduce and obfuscate the code:

buildTypes {
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}

2. Testing on different devicesUse Firebase Test Lab (free for limited quantities). tests) or manual testing on:

• 📱 Devices with different versions (from Android (from 7.0 to 14).
• 🔄 Different screen orientations (portrait/landscape).
• 🌍 Localizations (if you support several languages).

3. Preparation of materials for Google Play:

Element	Requirements	Tips
Application icon	Size 512×512 px, format PNG, without transparency	Use Canva or Adobe Illustrator for design
Screenshots	Minimum 2 pcs., resolution 1080×1920 px (for Google Pixel)	Show key features on the first screens
Description	Before 4000 characters, the first 80 characters are the most important (displayed in search)	Add keywords: "free", "without unnecessary water", "offline"
Video presentation	Duration up to 2 minutes, format MP4 or YouTube	Capture the screen using AZ Screen Recorder

⚠️ Attention: From August 31, 2023 Google Play requires filling out the section "Target audience" (age restrictions) and "Privacy Policy" (even if your application does not collect data). Without this, the publication will be rejected.

8. Play: step-by-step guide

When the application is ready, the last step remains - upload it to Google Play Console. Here's what you need to do:

1. Create a developer account:

   - Go to Google Play Console.

   - Pay the registration fee ($25 one-time).

   - Fill in your information (for individuals you will need a passport).

2. Create a new application:

   - Click Create App → specify the name (can be changed later), default language and application type (Application or Game).

3. Download APK/AAB:

   - In the section Production click Create new release.

   - Download the assembly file (.aab preferably, than .apk).

   - Specify version number (for example, 1.0.0) and version code (an integer, for example, 1).

4. Fill in information about the content:

   - Answer questions about the target audience, advertising, data collection.

   - Upload screenshots, icon and description.

5. Submit for review:

   - Click Review release → Start rollout to Production.

   - Wait for moderation (usually takes 1-3 days).

After approval, the application will become available in Google Play within several hours. Follow the statistics in Play Console: number of installations, user reviews and paint.

FAQ: Answers to frequently asked questions

How much does it cost to publish an application on Google Play?

Registration of a developer account costs $25 (further publication of applications is free, but Google beret 30% commissions from purchases and subscriptions (for the first $1 million revenue per year - 15%).

Is it possible to create an application without programming knowledge?

Yes, using constructors like Appy Pie, Thunkable or Adalo. However, the functionality will be limited to templates, and the code of such an application cannot be transferred to Android Studio for modification. For serious projects, it is better to study Kotlin or Java.

How to make money on an Android application?

Main monetization models:

• 💰 Paid application - the user pays for downloading.
• 📺 Advertising — integration AdMob or Facebook Audience Network.
• 🔄 In-app purchases —sale of premium features or virtual goods.
• 📊 Subscription —monthly payment for access to content.

The most popular option for beginners is advertising + free version with limited functionality.

What should I do if Google Play rejected my application?

Common reasons for rejection:

• 📄 Incomplete privacy policy.
• 🔞 Inconsistency with the target audience (for example, an application for children contains advertising).
• 🔗 Use of prohibited APIs (for example, REQUEST_INSTALL_PACKAGES without justification).
• 📱 Unstable operation on the latest versions Android.

The rejection letter Google indicates a specific reason. Correct it and submit the application for review again.

Do I need to test the application on real devices if I have an emulator?

Yes, definitely. The emulator does not always accurately reproduce:

• 🔋 Battery and background behavior.
• 📡 Work with mobile data (3G/4G/5G).
• 🎮 Performance on weak devices (for example, with 1 GB RAM).
• 🔊 Features of specific models (for example, a cutout in the screen of iPhone-like Android smartphones).

Minimum set for testing: one device for Android 10+ and one for Android 7–9.